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1
Feng, Hai-Ran, Xiang-Jia Meng, Peng Li, and Yu-Jun Zheng. "Dynamical correlation between quantum entanglement and intramolecular energy in molecular vibrations: An algebraic approach." Chinese Physics B 23, no. 7 (July 2014): 073301. http://dx.doi.org/10.1088/1674-1056/23/7/073301.
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HWA, RUDOLPH C. "GEOMETRICAL AND DYNAMICAL MULTIPLICITY FLUCTUATIONS IN HIGH-ENERGY NUCLEAR COLLISIONS." International Journal of Modern Physics A 04, no. 02 (January 1989): 481–92. http://dx.doi.org/10.1142/s0217751x89000248.
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General properties of multiplicity fluctuation in high-energy nuclear collisions are considered. Quantities that can directly be related to the geometrical and dynamical sources of the fluctuation are identified. Formalism for treating impact-parameter selection is discussed. The connection with correlation is described. Recent data indicate the absence of any significant collective behavior in the current experiments at the SPS. The observable that can reveal the onset of such behavior is suggested.
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MAKRI, NANCY, AKIRA NAKAYAMA, and NICHOLAS J. WRIGHT. "FORWARD-BACKWARD SEMICLASSICAL SIMULATION OF DYNAMICAL PROCESSES IN LIQUIDS." Journal of Theoretical and Computational Chemistry 03, no. 03 (September 2004): 391–417. http://dx.doi.org/10.1142/s0219633604001112.
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Forward-backward semiclassical dynamics (FBSD) provides a practical methodology for including quantum mechanical effects in classical trajectory simulations of polyatomic systems. FBSD expressions for time-dependent expectation values or correlation functions take the form of phase space integrals with respect to trajectory initial conditions, weighted by the coherent state transform of a corrected density operator. Quantization through a discretized path integral representation of the Boltzmann operator ensures a proper treatment of zero point energy effects and of imaginary components in finite-temperature correlation functions, and extension to systems obeying Bose statistics is possible. Accelerated convergence is achieved via Monte Carlo or molecular dynamics sampling techniques and through the construction of improved imaginary time propagators. The accuracy of the methodology is demonstrated on several model systems, including models of Bose and Fermi particles. Applications to liquid argon, neon and para-hydrogen are presented.
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Jeffreson, Sarah M. R., J. M. Diederik Kruijssen, Benjamin W. Keller, Mélanie Chevance, and Simon C. O. Glover. "The role of galactic dynamics in shaping the physical properties of giant molecular clouds in Milky Way-like galaxies." Monthly Notices of the Royal Astronomical Society 498, no. 1 (July 24, 2020): 385–429. http://dx.doi.org/10.1093/mnras/staa2127.
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ABSTRACT We examine the role of the large-scale galactic-dynamical environment in setting the properties of giant molecular clouds in Milky Way-like galaxies. We perform three high-resolution simulations of Milky Way-like discs with the moving-mesh hydrodynamics code arepo, yielding a statistical sample of ${\sim}80\, 000$ giant molecular clouds and ${\sim}55\, 000$ H i clouds. We account for the self-gravity of the gas, momentum, and thermal energy injection from supernovae and H ii regions, mass injection from stellar winds, and the non-equilibrium chemistry of hydrogen, carbon, and oxygen. By varying the external gravitational potential, we probe galactic-dynamical environments spanning an order of magnitude in the orbital angular velocity, gravitational stability, mid-plane pressure, and the gradient of the galactic rotation curve. The simulated molecular clouds are highly overdense (∼100×) and overpressured (∼25×) relative to the ambient interstellar medium. Their gravoturbulent and star-forming properties are decoupled from the dynamics of the galactic mid-plane, so that the kpc-scale star formation rate surface density is related only to the number of molecular clouds per unit area of the galactic mid-plane. Despite this, the clouds display clear, statistically significant correlations of their rotational properties with the rates of galactic shearing and gravitational free-fall. We find that galactic rotation and gravitational instability can influence their elongation, angular momenta, and tangential velocity dispersions. The lower pressures and densities of the H i clouds allow for a greater range of significant dynamical correlations, mirroring the rotational properties of the molecular clouds, while also displaying a coupling of their gravitational and turbulent properties to the galactic-dynamical environment.
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Finn, Molly K., Remy Indebetouw, Kelsey E. Johnson, Allison H. Costa, C. H. Rosie Chen, Akiko Kawamura, Toshikazu Onishi, et al. "Structural and Dynamical Analysis of the Quiescent Molecular Ridge in the Large Magellanic Cloud." Astronomical Journal 164, no. 2 (July 21, 2022): 64. http://dx.doi.org/10.3847/1538-3881/ac7aa1.
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Abstract We present a comparison of low-J 13CO and CS observations of four different regions in the LMC—the quiescent Molecular Ridge, 30 Doradus, N159, and N113, all at a resolution of ∼3 pc. The regions 30 Dor, N159, and N113 are actively forming massive stars, while the Molecular Ridge is forming almost no massive stars, despite its large reservoir of molecular gas and proximity to N159 and 30 Dor. We segment the emission from each region into hierarchical structures using dendrograms and analyze the sizes, masses, and line widths of these structures. We find that the Ridge has significantly lower kinetic energy at a given size scale and also lower surface densities than the other regions, resulting in higher virial parameters. This suggests that the Ridge is not forming massive stars as actively as the other regions because it has less dense gas and not because collapse is suppressed by excess kinetic energy. We also find that these physical conditions and energy balance vary significantly within the Ridge and that this variation appears only weakly correlated with distance from sites of massive-star formation such as R136 in 30 Dor, which is ∼1 kpc away. These variations also show only a weak correlation with local star formation activity within the clouds.
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Inoue, Hajime. "Wandering of the central black hole in a galactic nucleus and correlation of the black hole mass with the bulge mass." Publications of the Astronomical Society of Japan 73, no. 2 (February 16, 2021): 431–38. http://dx.doi.org/10.1093/pasj/psab009.
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Abstract We investigate a mechanism for a super-massive black hole at the center of a galaxy to wander in the nucleus region. A situation is supposed in which the central black hole tends to move by the gravitational attractions from the nearby molecular clouds in a nuclear bulge but is braked via the dynamical frictions from the ambient stars there. We estimate the approximate kinetic energy of the black hole in an equilibrium between the energy gain rate through the gravitational attractions and the energy loss rate through the dynamical frictions in a nuclear bulge composed of a nuclear stellar disk and a nuclear stellar cluster as observed from our Galaxy. The wandering distance of the black hole in the gravitational potential of the nuclear bulge is evaluated to get as large as several 10 pc, when the black hole mass is relatively small. The distance, however, shrinks as the black hole mass increases, and the equilibrium solution between the energy gain and loss disappears when the black hole mass exceeds an upper limit. As a result, we can expect the following scenario for the evolution of the black hole mass: When the black hole mass is smaller than the upper limit, mass accretion of the interstellar matter in the circumnuclear region, causing the AGN activities, makes the black hole mass larger. However, when the mass gets to the upper limit, the black hole loses the balancing force against the dynamical friction and starts spiraling downward to the gravity center. From simple parameter scaling, the upper mass limit of the black hole is found to be proportional to the bulge mass, and this could explain the observed correlation of the black hole mass with the bulge mass.
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Bonačič-Koutecký, Vlasta, Detlef Reichardt, Jiří Pittner, Piercarlo Fantucci, and Jaroslav Koutecký. "Ab initio Molecular Dynamics for Determination of Structures of Alkali Metal Clusters and Their Temperatures Behavior; An Example of Li9+." Collection of Czechoslovak Chemical Communications 63, no. 9 (1998): 1431–46. http://dx.doi.org/10.1135/cccc19981431.
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It will be shown that an ab initio molecular dynamics procedure based on gradient corrected density functionals for exchange and correlation and using a Gaussian atomic basis (AIMD-GDF) implemented for parallel processing represents a suitable tool for detailed and accurate investigation of structural and dynamical properties of small systems. Gradients of the Born-Oppenheimer ground state energy, obtained by iterative solution of the Kohn-Sham equations, are used to calculate the forces acting on atoms at each instantaneous configuration along trajectories generated by solving classical equations of motion. Dynamics of different isomers of the Li9+ cluster have been investigated as a function of excess energy. It is shown that different isomers, even those similar in energy, can exhibit different structural and dynamical behavior. The analysis of the simulations leads to the conclusion that structures with a central atom, in particular the centered antiprism of Li9+ exhibit concerted mobility of the peripheral atoms at relatively low excess energy. In contrast, compact tetrahedral type structures show much more rigid behavior at low excess energy. However, the former ones need larger excess of internal energy to undergo isomerizations to geometrically different structures than the latter ones. At the time scale of our simulations we found that for the intermediate excess energies it is "easier" to carry the cluster in the basin of the lowest energy isomer than in the reverse direction. It has been found that the liquid-like behavior in small Li clusters becomes apparent at relatively high temperature in spite of large mobility of their atoms.
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Yuan, Qiang, and Xi-Wen Hou. "Entropy, energy, and entanglement of localized states in bent triatomic molecules." International Journal of Modern Physics B 31, no. 12 (May 10, 2017): 1750088. http://dx.doi.org/10.1142/s0217979217500886.
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The dynamics of quantum entropy, energy, and entanglement is studied for various initial states in an important spectroscopic Hamiltonian of bent triatomic molecules H2O, D2O, and H2S. The total quantum correlation is quantified in terms of the mutual information and the entanglement by the concurrence borrowed from the theory of quantum information. The Pauli entropy and the intramolecular energy usually used in the theory of molecules are calculated to establish a possible relationship between both theories. Sections of two quantities among these four quantities are introduced to visualize such relationship. Analytic and numerical simulations demonstrate that if an initial state is taken to be the stretch- or the bend-vibrationally localized state, the mutual information, the Pauli entropy, and the concurrence are dominant-positively correlated while they are dominantly anti-correlated with the interacting energy among three anharmonic vibrational modes. In particular, such correlation is more distinct for the localized state with high excitations in the bending mode. The nice quasi-periodicity of those quantities in D2O molecule reveals that this molecule prepared in the localized state in the stretching or the bending mode can be more appreciated for molecular quantum computation. However, the dynamical correlations of those quantities behave irregularly for the dislocalized states. Moreover, the hierarchy of the mutual information and the Pauli entropy is explicitly proved. Quantum entropy and energy in every vibrational mode are investigated. Thereby, the relation between bipartite and tripartite entanglements is discussed as well. Those are useful for the understanding of quantum correlations in high-dimensional states in polyatomic molecules from quantum information and intramolecular dynamics.
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Falgarone, E. "Turbulence in Interstellar Clouds." International Astronomical Union Colloquium 120 (1989): 68–79. http://dx.doi.org/10.1017/s0252921100023496.
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Above masses of the order of lOO M⊙, molecular clouds have masses and sizes which scale like those of self-gravitating polytropes bounded by an external pervading pressure. It is unlikely that this scaling is due to mere observational bias. But the physics underlying this behaviour is far from being understood. In particular, the possible contribution of turbulence to both the ambient pressure and the internal pressure (whose dependence with the density would mimic a polytropic behavior) is a difficult and much debated issue. The clouds mass, size and internal velocity dispersion are such that they are observed to be in approximate virial balance between their self-gravity, the surface energy term due to the ambient pressure and their internal energy. The latter is dominated by the kinetic energy of disordered internal motions. However, there has been little evidence so far that these motions are actually turbulent rather than simply disordered. The transition to turbulence in a flow occurs when the non linear advection term in the momentum equation, v.Δv, considerably exceeds the viscous dissipation term, vΔv (where v is the kinematic viscosity). Non linearities therefore dominate the physics of a turbulent flow and the velocities are not randomly distributed. Most of the previous attempts to determine a well-defined correlation length in the velocity field (Kleiner and Dickman 1985, a and b; Scalo 1984), which is predicted to be close to the scale at which the energy is injected, or to characterize the expected hierarchical structure (Pérault et al. 1986) have been plagued by the lack of dynamical range in the data set and the range of scales over which the correlation functions have been computed. The most plausible determination, that of Kleiner and Dickman (1987) who claim to have found a correlation length of 0.2 pc in the Taurus cloud, gives a result which is so close to the angular resolution of the observations that it is doubtful.
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Toscano, Giuseppe, and Daniele Duca. "RENEWABLE ENERGY CONTENT OF FATTY ACID METHYL ESTERS (FAME) AND GLYCEROL." Journal of Agricultural Engineering 40, no. 4 (December 31, 2009): 47. http://dx.doi.org/10.4081/jae.2009.90.
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Fatty acid methyl esters (FAME) and glycerol produced by transesterification reaction contain atoms that in the reagents belong to methanol and, therefore, are not renewable. A method to evaluate the content of the renewable and non-renewable energetic fraction, released during their combustion, was 52 Fig. 2 - Correlation between EFNR and NCM of FAME. Fig. 3 - Correlation between NCM and NS. Fig. 4 - Correlations between EFNR and NS. 07_Toscano(541)_47 26-01-2010 9:35 Pagina 52 developed using a thermochemical criteria, based on bond dissociation energies and the knowledge of the molecular structure of the reagents and the products. Results show that the fraction of non-renewable energy in the most diffused FAME is lower than 1% depending on the lengths of the carbonaceous methyl esters. Meanwhile, the energetic supply for the GL of this fraction is about 1.6%. The data reported in this document can be used to develop a criteria that corrects the fiscal mechanism aspects of some renewable energy products.
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Husain, Mudassir M., Zahid H. Khan, and Edwin Haselbach. "Prediction of the Lowest-Energy Non-Koopmans Doublet States and the First Ionization Potentials of Polycyclic Aromatic Systems from Their Triplet-State Energies." Applied Spectroscopy 49, no. 6 (June 1995): 852–56. http://dx.doi.org/10.1366/0003702953964534.
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This paper presents some new relations connecting the triplet-state energy of an alternant aromatic hydrocarbon with that of its excited doublet state as well as its first ionization potential. The energy relation between the doublet and triplet states is basically a simplified version of the SDT relation but the predictive power of the proposed correlation is considerably better in spite of the drastic assumptions made in the model. Incorporation of molecular size in the doublet-triplet correlation has no appreciable effect on the predictions, but its inclusion in the ionization potential vs. triplet-state energy relation leads to a significant improvement in the results. It is explained on the basis of our new finding that the Coulomb term appearing in the expression for the ionization potential behaves in the same manner as the molecular size, which thus accounts for electron interaction in the model. The proposed correlations provide a simple but powerful means to estimate the first ionization potentials and excited doublet-state energies of polycyclic aromatic hydrocarbons directly from the knowledge of their triplet-state energies.
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FACCIOLI, PIETRO. "INSTANTON-INDUCED CORRELATIONS IN HADRONS." International Journal of Modern Physics A 20, no. 19 (July 30, 2005): 4615–21. http://dx.doi.org/10.1142/s0217751x05028284.
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QCD instantons generate non-perturbative spin- and flavor- dependent correlations between light quarks. We report on the results of a series of studies on the contribution of instantons to the electro-weak structure of light hadrons. We show that the Instanton Liquid Model can reproduce the available data on proton and pion form factors at large momentum transfer, and explain the delay of the onset of the perturbative regime in some exclusive reactions. We provide unambiguous evidence that instantons lead to the formation of a deeply bound scalar, color anti-triplet diquark, with a mass of about 450 MeV. The strong attraction in the [Formula: see text], scalar diquark channel leads to a quantitative description of non-leptonic decays of hyperons and provides a microscopic dynamical explanation of the Δ I = 1/2 rule.
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Huang, Kaisheng, Yi Liu, Shuixiu Wen, Yuxin Zhao, Hanjing Ding, Hui Liu, and De-Xin Kong. "Binding Mechanism of CD47 with SIRPα Variants and Its Antibody: Elucidated by Molecular Dynamics Simulations." Molecules 28, no. 12 (June 7, 2023): 4610. http://dx.doi.org/10.3390/molecules28124610.
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The intricate complex system of the differentiation 47 (CD47) and the signal-regulatory protein alpha (SIRPα) cluster is a crucial target for cancer immunotherapy. Although the conformational state of the CD47-SIRPα complex has been revealed through crystallographic studies, further characterization is needed to fully understand the binding mechanism and to identify the hot spot residues involved. In this study, molecular dynamics (MD) simulations were carried out for the complexes of CD47 with two SIRPα variants (SIRPαv1, SIRPαv2) and the commercially available anti-CD47 monoclonal antibody (B6H12.2). The calculated binding free energy of CD47-B6H12.2 is lower than that of CD47-SIRPαv1 and CD47-SIRPαv2 in all the three simulations, indicating that CD47-B6H12.2 has a higher binding affinity than the other two complexes. Moreover, the dynamical cross-correlation matrix reveals that the CD47 protein shows more correlated motions when it binds to B6H12.2. Significant effects were observed in the energy and structural analyses of the residues (Glu35, Tyr37, Leu101, Thr102, Arg103) in the C strand and FG region of CD47 when it binds to the SIRPα variants. The critical residues (Leu30, Val33, Gln52, Lys53, Thr67, Arg69, Arg95, and Lys96) were identified in SIRPαv1 and SIRPαv2, which surround the distinctive groove regions formed by the B2C, C’D, DE, and FG loops. Moreover, the crucial groove structures of the SIRPα variants shape into obvious druggable sites. The C’D loops on the binding interfaces undergo notable dynamical changes throughout the simulation. For B6H12.2, the residues Tyr32LC, His92LC, Arg96LC, Tyr32HC, Thr52HC, Ser53HC, Ala101HC, and Gly102HC in its initial half of the light and heavy chains exhibit obvious energetic and structural impacts upon binding with CD47. The elucidation of the binding mechanism of SIRPαv1, SIRPαv2, and B6H12.2 with CD47 could provide novel perspectives for the development of inhibitors targeting CD47-SIRPα.
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Ouvrard, Carole, and John B. O. Mitchell. "Can we predict lattice energy from molecular structure?" Acta Crystallographica Section B Structural Science 59, no. 5 (September 25, 2003): 676–85. http://dx.doi.org/10.1107/s0108768103019025.
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By using simply the numbers of occurrences of different atom types as descriptors, a conceptually transparent and remarkably accurate model for the prediction of the enthalpies of sublimation of organic compounds has been generated. The atom types are defined on the basis of atomic number, hybridization state and bonded environment. Models of this kind were applied firstly to aliphatic hydrocarbons, secondly to both aliphatic and aromatic hydrocarbons, thirdly to a wide range of non-hydrogen-bonding molecules, and finally to a set of 226 organic compounds including 70 containing hydrogen-bond donors and acceptors. The final model gives squared correlation coefficients of 0.925 for the 226 compounds in the training set and 0.937 for an independent test set of 35 compounds. The success of such a simple model implies that the enthalpy of sublimation can be predicted accurately without knowledge of the crystal packing. This hypothesis is in turn consistent with the idea that, rather than being determined by the particular features of the lowest-energy packing, the lattice energy is similar for a number of hypothetical alternative crystal structures of a molecule.
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XU, MINGMEI, and LIANSHOU LIU. "ON THE DYNAMICAL FLUCTUATION OF SINGLE-EVENT TRANSVERSE MOMENTUM DISTRIBUTION." International Journal of Modern Physics A 21, no. 26 (October 20, 2006): 5241–52. http://dx.doi.org/10.1142/s0217751x06032964.
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Assuming that the single-event transverse momentum distribution fluctuates event by event according to a distribution functional, we derive analytical expressions for both the variance of event-wise mean transverse momentum and the two-particle transverse momentum correlation. The relation between these two is discussed. An evaluation of statistical fluctuation is given. An exponential form for the single-event transverse momentum distribution is taken as an example to demonstrate our method for extracting event-by-event dynamical fluctuation of single-event transverse momentum distribution from experimental data.
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Carroll, M. T., R. F. W. Bader, and S. H. Vosko. "Local and non-local spin density functional calculations of the correlation energy of atoms in molecules." Journal of Physics B: Atomic and Molecular Physics 20, no. 15 (August 14, 1987): 3599–629. http://dx.doi.org/10.1088/0022-3700/20/15/011.
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ZALALETDINOV, ROUSTAM. "THE AVERAGING PROBLEM IN COSMOLOGY AND MACROSCOPIC GRAVITY." International Journal of Modern Physics A 23, no. 08 (March 30, 2008): 1173–81. http://dx.doi.org/10.1142/s0217751x08040032.
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The averaging problem in cosmology and the approach of macroscopic gravity to resolve the problem is discussed. The averaged Einstein equations of macroscopic gravity are modified on cosmological scales by the macroscopic gravitational correlation tensor terms as compared with the Einstein equations of general relativity. This correlation tensor satisfies a system of structure and field equations. An exact cosmological solution to the macroscopic gravity equations for a constant macroscopic gravitational connection correlation tensor for a flat spatially homogeneous, isotropic macroscopic space-time is presented. The correlation tensor term in the macroscopic Einstein equations has been found to take the form of either a negative or positive spatial curvature term. Thus, macroscopic gravity provides a cosmological model for a flat spatially homogeneous, isotropic Universe which obeys the dynamical law for either an open or closed Universe.
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Chatzidimitriou-Dreismann, C. Aris. "Quantum Beam Scattering—Beam’s Coherence Length, Which-Path Information and Weak Values." Quantum Beam Science 7, no. 3 (August 15, 2023): 26. http://dx.doi.org/10.3390/qubs7030026.
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The conventional theory of neutron beams interacting with many-body systems treats the beam as a classical system, i.e., with its dynamical variables appearing in the quantum dynamics of the scattering process not as operators but only as c-numbers. Moreover, neutrons are described with plane waves, i.e., the concept of a neutron’s (finite) coherence length is here irrelevant. The same holds for electron, atom or X-ray scattering. This simplification results in the full decoupling of the probe particle’s dynamics from the quantum dynamics of the scatterer—a well-known fact also reflected in the standard formalism of time-correlation functions (see textbooks). Making contact with modern quantum-theoretical approaches (e.g., quantum entanglement, “which-path information” versus interference, von Neumann measurement, Weak Values (WV), etc.), new observable effects of non-relativistic quantum beam scattering may be exposed and/or predicted, for instance, a momentum-transfer deficit and an intensity deficit in neutron scattering from protons of hydrogen-containing samples. A new WV-theoretical treatment is provided, which explains both these “deficit effects” from first principles and on equal footing.
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Platts, James A., and J. Grant Hill. "Non-covalent interactions using local correlation methods: energy partitioning, geometry optimisation and harmonic frequency calculations." Molecular Physics 108, no. 11 (June 10, 2010): 1497–504. http://dx.doi.org/10.1080/00268971003757977.
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FARIA DA VEIGA, PAULO A., and MICHAEL O'CARROLL. "EXACT DYNAMICAL EIGHTFOLD WAY BARYON SPECTRUM AND CONFINEMENT IN STRONGLY COUPLED LATTICE QCD." International Journal of Modern Physics A 24, no. 16n17 (July 10, 2009): 3053–72. http://dx.doi.org/10.1142/s0217751x09043183.
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We obtain from the quark–gluon dynamics the eightfold way baryon spectrum exactly in an imaginary time functional integral formulation of 3+1 lattice QCD with Wilson's action in the strong coupling regime (small hopping parameter 0 < κ ≪ 1 and much smaller plaquette coupling [Formula: see text]). The model has SU(3)c local gauge and global SU(3)f flavor symmetries. A decoupling of the hyperplane method naturally unveils the form of the baryon composite fields. In the subspace of the physical Hilbert space of vectors with an odd number of quarks, the baryons are associated with isolated dispersion curves in the energy–momentum spectrum. Spectral representations are derived for the two-baryon correlations, which allow us to detect the energy–momentum spectrum and particles as complex momentum space singularities. The spin 1/2 octet and spin 3/2 decuplet baryons have asymptotic mass -3ln κ and for each baryon there is an antibaryon with identical spectral properties. An auxiliary function method is used to obtain convergent expansions for the masses after subtracting the singular part -3ln κ. The nonsingular part of the mass is analytic in κ and β, i.e. the expansions are controlled to all orders. For β = 0, all the masses have the form M = -3ln κ - 3κ3/4 + κ6r(κ), with r(κ) real analytic. Although we have no Lorentz symmetry in our lattice model, we show that there is a partial restoration of the continuous rotational symmetry at zero spatial momentum, which implies that for all members of the octet (decuplet) r(κ) is the same. So, there is no mass splitting within the octet and within the decuplet. However, there is an octet–decuplet mass difference of [Formula: see text] at β = 0; the splitting persists for β ≠ 0. We also obtain the (anti)baryon dispersion curves which admit the representation [Formula: see text], where [Formula: see text] and [Formula: see text] is of [Formula: see text]. For the octet, [Formula: see text] is jointly analytic in κ and in each pj, for small [Formula: see text]. A new local symmetry, which we call spin flip, is used to establish constraints for the matrix-valued two-baryon correlation and show that all the octet dispersion curves are the same and that the four decuplet dispersion curves are pairwise-identical and depend only on the modulus of the spin z-component. Using a correlation subtraction method we show that the spectrum generated by the baryon and antibaryon fields is the only spectrum, in the odd quark subspace of physical states, up to near the baryon–meson threshold of ≈ -5ln κ. Combining this result with a similar result for the mesons, with mass ≈ -2ln κ, shows that the only spectrum in the entire space of states, up to near the two-meson threshold of ≈ -4ln κ, is generated by the eightfold way hadrons. Hence, for 0 < κ ≪ β ≪ 1, we have shown confinement up to near this threshold.
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Sharif, M., and M. Zeeshan Gul. "Dynamics of spherical collapse in energy–momentum squared gravity." International Journal of Modern Physics A 36, no. 01 (January 10, 2021): 2150004. http://dx.doi.org/10.1142/s0217751x21500044.
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This paper investigates the dynamics of spherical collapse in the framework of energy–momentum squared gravity. This theory overcomes the big-bang singularity and provides viable cosmological consequences in the early time universe. We proceed our work by considering the nonstatic spherically symmetric space–time in the interior and static spherically symmetric metric in the exterior regions of the star. The Darmois junction conditions between interior and exterior geometries are derived. We construct dynamical equations through the Misner–Sharp technique to analyze the impact of matter variables and dark source terms on the collapsing phenomenon. A correlation among dark source terms, Weyl scalar and matter variables is also established. Due to the presence of multivariate function and its derivatives, space–time is no longer considered to be conformally flat. To obtain conformally flat space–time, we have considered a particular model of this gravity which yields conformally flat space–time and homogeneity of the energy density through the entire system. We conclude that positive dark source terms as well as negative pressure gradient provide the anti-gravitational behavior leading to the stability of self-gravitating objects and hence prevent the collapsing process.
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Ghosh, D., A. K. Jafry, A. Deb, R. Chattopadhyay, S. Das, M. Lahiri, B. Biswas, K. Purkait, S. Das, and J. Roychoudhury. "Evidence of dynamical many-particle correlation in heavy-ion interactions at 60AGeV/c and 200AGeV/c." Il Nuovo Cimento A 111, no. 12 (December 1998): 1361–66. http://dx.doi.org/10.1007/bf03035999.
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Schwilk, Max, Pál D. Mezei, Diana N. Tahchieva, and O. Anatole von Lilienfeld. "Non-covalent interactions between molecular dimers (S66) in electric fields." Electronic Structure 4, no. 1 (February 9, 2022): 014005. http://dx.doi.org/10.1088/2516-1075/ac4eeb.
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Abstract Fine tuning and microscopic control of van der Waals interactions through oriented external electric fields (OEEFs) mandates an accurate and systematic understanding of intermolecular response properties. Having taken exploratory steps into this direction, we present a systematic study of interaction induced dipole electric properties of all molecular dimers in the S66 set, relying on CCSD(T)-F12b/aug-cc-pVDZ-F12 as reference level of theory. For field strengths up to ≈5 GV m−1 the interaction induced electric response beyond second order is found to be insignificant. Large interaction dipole moments (i.e. dipole moment changes due to van der Waals binding) are observed in the case of hydrogen bonding oriented along the intermolecular axis, and mostly small interaction dipole moments are found in dimers bonded by π-stacking or London dispersion. The interaction polarizabilities (i.e. polarizability changes due to van der Waals binding) were generally found to be small but always with a positive-valued principal component approximately aligned with the intermolecular axis, and two other negative-valued components. Energy decompositions according to symmetry adapted perturbation theory (SAPT0/jun-cc-pVDZ) suggest that electrostatics dominates the interaction dipole moment, with exchange and induction contributing on a smaller scale, and with dispersion having the smallest effect. First-order SAPT0 decomposition into monomer-resolved contributions enables us to establish a quantitative link between electric properties of monomers and dimers, which is found to be in qualitative agreement with the coupled cluster reference method. Using the aug-cc-pVQZ basis and non-empirical Perdew–Burke–Ernzerhof (PBE) semilocal exchange–correlation kernels, we also assess how density functional approximations in the nonlocal exchange and correlation parts affect the predictive accuracy: while dRPA@PBE0 based predictions are in excellent overall agreement with coupled cluster results, the computationally more affordable LC-ωPBE0-D3 level of theory also yields reliable results with relative errors below 5%. PBE alone, even when dispersion corrected, produces larger errors in interaction dipole moments (≈10%) and polarizabilities (≈20%). We also resolve the mutual impact of the three dimensions of the OEEF, and we present a discussion of the intermolecular distance dependence of the perturbations.
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Xu, Qiushuang, Yanli Liu, Meishan Wang, Javier Cerezo, Roberto Improta, and Fabrizio Santoro. "The Resonance Raman Spectrum of Cytosine in Water: Analysis of the Effect of Specific Solute–Solvent Interactions and Non-Adiabatic Couplings." Molecules 28, no. 5 (March 1, 2023): 2286. http://dx.doi.org/10.3390/molecules28052286.
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In this contribution, we report a computational study of the vibrational Resonance Raman (vRR) spectra of cytosine in water, on the grounds of potential energy surfaces (PES) computed by time-dependent density functional theory (TD-DFT) and CAM-B3LYP and PBE0 functionals. Cytosine is interesting because it is characterized by several close-lying and coupled electronic states, challenging the approach commonly used to compute the vRR for systems where the excitation frequency is in quasi-resonance with a single state. We adopt two recently developed time-dependent approaches, based either on quantum dynamical numerical propagations of vibronic wavepackets on coupled PES or on analytical correlation functions for cases in which inter-state couplings were neglected. In this way, we compute the vRR spectra, considering the quasi-resonance with the eight lowest-energy excited states, disentangling the role of their inter-state couplings from the mere interference of their different contributions to the transition polarizability. We show that these effects are only moderate in the excitation energy range explored by experiments, where the spectral patterns can be rationalized from the simple analysis of displacements of the equilibrium positions along the different states. Conversely, at higher energies, interference and inter-state couplings play a major role, and the adoption of a fully non-adiabatic approach is strongly recommended. We also investigate the effect of specific solute–solvent interactions on the vRR spectra, by considering a cluster of cytosine, hydrogen-bonded by six water molecules, and embedded in a polarizable continuum. We show that their inclusion remarkably improves the agreement with the experiments, mainly altering the composition of the normal modes, in terms of internal valence coordinates. We also document cases, mostly for low-frequency modes, in which a cluster model is not sufficient, and more elaborate mixed quantum classical approaches, in explicit solvent models, need to be applied.
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Ganguly, S., and V. Gopalakrishnan. "3D QSAR Studies of DAMNI Analogs as Possible Non-nucleoside Reverse Transcriptase Inhibitors." E-Journal of Chemistry 5, s2 (2008): 1103–13. http://dx.doi.org/10.1155/2008/712930.
Full textAbstract:
The non-nucleoside inhibitors ofHIV-1-reverse transcriptase (NNRTIs) are an important class of drugs employed in antiviral therapy. Recently, a novel family ofNNRTIs commonly referred to as 1-[2-diarylmethoxy] ethyl) 2-methyl-5-nitroimidazoles (DAMNI) derivatives have been discovered. The 3D-QSARstudies onDAMNIderivatives asNNRTIs was performed by comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) methods to determine the factors required for the activity of these compounds. The global minimum energy conformer of the template molecule 15, the most active molecule of the series, was obtained by simulated annealing method and used to build the structures of the molecules in the dataset. The combination of steric and electrostatic fields inCoMSIAgave the best results with cross-validated and conventional correlation coefficients of 0.654 and 0.928 respectively. The predictive ability ofCoMFAandCoMSIAwere determined using a test set of tenDAMNIderivatives giving predictive correlation coefficients of 0.92 and 0.98 respectively indicating good predictive power. Further, the robustness of the models was verified by bootstrapping analysis. The information obtained fromCoMFAandCoMSIA3Dcontour maps may be of utility in the design of more potentDAMNIanalogs asNNRTIs in future.
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Chachiyo, Teepanis, and Hathaithip Chachiyo. "Simple and Accurate Exchange Energy for Density Functional Theory." Molecules 25, no. 15 (July 31, 2020): 3485. http://dx.doi.org/10.3390/molecules25153485.
Full textAbstract:
A non-empirical exchange functional based on an interpolation between two limits of electron density, slowly varying limit and asymptotic limit, is proposed. In the slowly varying limit, we follow the study by Kleinman from 1984 which considered the response of a free-electron gas to an external periodic potential, but further assume that the perturbing potential also induces Bragg diffraction of the Fermi electrons. The interpolation function is motivated by the exact exchange functional of a hydrogen atom. Combined with our recently proposed correlation functional, tests on 56 small molecules show that, for the first-row molecules, the exchange-correlation combo predicts the total energies four times more accurately than the presently available Quantum Monte Carlo results. For the second-row molecules, errors of the core electrons exchange energies can be corrected, leading to the most accurate first- and second-row molecular total energy predictions reported to date despite minimal computational efforts. The calculated bond energies, zero point energies, and dipole moments are also presented, which do not outperform other methods.
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Brünger, A. T. "Extension of molecular replacement: a new search strategy based on Patterson correlation refinement." Acta Crystallographica Section A Foundations of Crystallography 46, no. 1 (January 1, 1990): 46–57. http://dx.doi.org/10.1107/s0108767389009633.
Full textAbstract:
A new search strategy is presented to obtain initial phases for single-crystal diffraction data by molecular replacement. It consists of carrying out 'Patterson refinements' of a large number of the highest peaks of a rotation function. The target function for Patterson refinement is proportional to the negative correlation coefficient between the squared amplitudes of the observed and the calculated normalized structure factors. If the root-mean-square difference between the search model and the crystal structure is within the radius of convergence of the minimization procedure employed, the correct orientation can be identified by having the lowest value of the target function after refinement. Similar to conventional crystallographic R-factor refinement, the target function for Patterson refinement may be combined with an empirical energy function describing geometric and non-bonded interactions. Patterson refinement of individual atomic coordinates or of rigid-group parameters may be carried out. Search models of crambin and of myoglobin with 1.6-2.0 Å backbone atomic r.m.s, differences from the target crystal structures show that the Patterson refinement strategy can solve crystal structures that cannot be solved by conventional molecular replacement or even by full six-dimensional searches.
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Kondo, Toru, Jesse B. Gordon, Alberta Pinnola, Luca Dall’Osto, Roberto Bassi, and Gabriela S. Schlau-Cohen. "Microsecond and millisecond dynamics in the photosynthetic protein LHCSR1 observed by single-molecule correlation spectroscopy." Proceedings of the National Academy of Sciences 116, no. 23 (May 17, 2019): 11247–52. http://dx.doi.org/10.1073/pnas.1821207116.
Full textAbstract:
Biological systems are subjected to continuous environmental fluctuations, and therefore, flexibility in the structure and function of their protein building blocks is essential for survival. Protein dynamics are often local conformational changes, which allows multiple dynamical processes to occur simultaneously and rapidly in individual proteins. Experiments often average over these dynamics and their multiplicity, preventing identification of the molecular origin and impact on biological function. Green plants survive under high light by quenching excess energy, and Light-Harvesting Complex Stress Related 1 (LHCSR1) is the protein responsible for quenching in moss. Here, we expand an analysis of the correlation function of the fluorescence lifetime by improving the estimation of the lifetime states and by developing a multicomponent model correlation function, and we apply this analysis at the single-molecule level. Through these advances, we resolve previously hidden rapid dynamics, including multiple parallel processes. By applying this technique to LHCSR1, we identify and quantitate parallel dynamics on hundreds of microseconds and tens of milliseconds timescales, likely at two quenching sites within the protein. These sites are individually controlled in response to fluctuations in sunlight, which provides robust regulation of the light-harvesting machinery. Considering our results in combination with previous structural, spectroscopic, and computational data, we propose specific pigments that serve as the quenching sites. These findings, therefore, provide a mechanistic basis for quenching, illustrating the ability of this method to uncover protein function.
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Choi, Min Kyu, and Ki Chul Kim. "Strategic Development of Dielectric Strength Prediction Protocol for Perfluorocarbon and Nonperfluorocarbon Compounds." Applied Sciences 13, no. 7 (March 29, 2023): 4318. http://dx.doi.org/10.3390/app13074318.
Full textAbstract:
Predicting the dielectric strengths of organic compounds is critical for identifying potential insulating gases. However, experimental evaluation techniques are time-consuming, and current computational protocols are limited in scope. In this study, to develop a reliable prediction protocol for the dielectric strengths of a broad array of perfluorocarbon (PFC) and non-PFC compounds, systematic linear regression is combined with computational calculations of relevant core factors. The designed equation-based protocol is demonstrated to have four core factors, including two high-correlation factors (polarizability and molecular weight) and two critical factors (ionization energy and highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) gap). The two critical factors are crucial for determining a suitable protocol, as reliable predictions of dielectric strength are only possible if the ionization energy and HOMO–LUMO gap are maintained within specified ranges for all the compounds. These findings can act as design guidelines for future computational protocols to predict the insulating properties of PFC and non-PFC compounds.
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Fernández, Julio A. "The formation and dynamical survival of the comet cloud." International Astronomical Union Colloquium 83 (1985): 45–70. http://dx.doi.org/10.1017/s0252921100083792.
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AbstractThe theory of a huge reservoir of comets (the “comet cloud”) extending to almost interstellar distances is analyzed, paying special attention to its dynamical stability, formation process and orbital properties of the incoming cloud comets. The perturbing influence of passing stars and giant molecular clouds is considered. Giant molecular clouds may be an important perturbing element of the comet cloud, although they do not seem to change drastically former studies including only stellar perturbations. The more tightly bound inner portions of the comet cloud, say within 104 AU, would have withstood the disrupting forces over the age of the solar system. The theory of a primordial comet origin in the outer planetary region close to Neptune’s orbit is specially analyzed. A primordial comet origin is consistent with the cosmogonic view that a large amount of residual material was ejected during the last stage in the formation of the Jovian planets. The smooth diffusion in the energy space of bodies scattered by Neptune guarantees that most of them will fall in the narrow range of energies close to zero (near-parabolic orbits) where passing stars and GMCs can act effectively on them. The long time scales of ~109 yr required for bodies scattered by Neptune to reach near-parabolic orbits would indicate that the buildup of the comet cloud was an event that took place long after the planets formed. Depending on the field of perturbing galactic objects, it is possible to conceive that most scattered comets were stored in rather tightly bound orbits (a ~l04 AU), favoring the concept of their dynamical survival over several billion yr. Alternative theories of comet cloud formation, e.g. in-situ origin or interstellar capture, are also discussed. The main difficulty of the in-situ theory is to explain how comets could accumulate at large heliocentric distances where the density of the nebular material was presumably very low. The interstellar capture theory also meets severe dynamical objections as, for instance, the lack of observed comets with original strongly hyperbolic orbits and the extremely low probability of capture under most plausible conditions. Since our knowledge of the structure of giant molecular clouds and their frequency of encounters with the solar system is still very uncertain, the concept of capture of transient comet clouds during such encounters can be advanced very little beyond the speculative stage. Some other dynamical properties of relevance to theories of origin and structure of the comet cloud are also reviewed. We mention, for instance, the distribution of perihelion points on the celestial sphere. There seems to be here a well established deviation from randomness, although the debate on whether or not there is a preference of the perihelion clustering for the vicinity of the apex of the solar motion is still unsettled. The alleged correlation with the solar apex may be biased by the preference of comet discoveries in the northern hemisphere. Deviations from randomness might be caused by very close stellar passages in the recent past. The excess of retrograde orbits among the observed “new” and young comets - mainly those with q ≳ 2 AU - is another well known dynamical feature. Such an excess may probably be accounted for by the combined action of planetary and stellar perturbations. Because of the decreasing action of planetary perturbations with increasing heliocentric distances, a significant increase in the rate of passages of long-period comets is predicted for the outer planetary region.
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Ignatenko, A. V., E. L. Ponomarenko, A. S. Kvasikova, and T. A. Kulakli. "ON DETERMINATION OF RADIATIVE TRANSITIONS PROBABILITIES IN RELATIVISTIC THEORY OF DIATOMIC MOLECULES: NEW SCHEME." Photoelectronics, no. 24 (December 1, 2015): 116–21. http://dx.doi.org/10.18524/0235-2435.2015.24.158163.
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On the basis of new gauge-invariant scheme in the relativistic energy approach combined with the multibody perturbation theory for diatomic molecules it is formulated a new theoretical scheme for calculating the probabilities of radiative transitions of molecules. It is analysed the possible way to take into account for the inter-electron correlation and correspondingly the non-gauge-invariant contributions in relativistic molecular theory.
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Zhou, Mengran, Shuai Shao, Xu Wang, Ziwei Zhu, and Feng Hu. "Deep Learning-Based Non-Intrusive Commercial Load Monitoring." Sensors 22, no. 14 (July 13, 2022): 5250. http://dx.doi.org/10.3390/s22145250.
Full textAbstract:
Commercial load is an essential demand-side resource. Monitoring commercial loads helps not only commercial customers understand their energy usage to improve energy efficiency but also helps electric utilities develop demand-side management strategies to ensure stable operation of the power system. However, existing non-intrusive methods cannot monitor multiple commercial loads simultaneously and do not consider the high correlation and severe imbalance among commercial loads. Therefore, this paper proposes a deep learning-based non-intrusive commercial load monitoring method to solve these problems. The method takes the total power signal of the commercial building as input and directly determines the state and power consumption of several specific appliances. The key elements of the method are a new neural network structure called TTRNet and a new loss function called MLFL. TTRNet is a multi-label classification model that can autonomously learn correlation information through its unique network structure. MLFL is a loss function specifically designed for multi-label classification tasks, which solves the imbalance problem and improves the monitoring accuracy for challenging loads. To validate the proposed method, experiments are performed separately in seen and unseen scenarios using a public dataset. In the seen scenario, the method achieves an average F1 score of 0.957, which is 7.77% better than existing multi-label classification methods. In the unseen scenario, the average F1 score is 0.904, which is 1.92% better than existing methods. The experimental results show that the method proposed in this paper is both effective and practical.
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Zeb, Amir, Chanin Park, Minky Son, Shailima Rampogu, Syed Ibrar Alam, Seok Ju Park, and Keun Woo Lee. "Investigation of non-hydroxamate scaffolds against HDAC6 inhibition: A pharmacophore modeling, molecular docking, and molecular dynamics simulation approach." Journal of Bioinformatics and Computational Biology 16, no. 03 (June 2018): 1840015. http://dx.doi.org/10.1142/s0219720018400152.
Full textAbstract:
Proteins deacetylation by Histone deacetylase 6 (HDAC6) has been shown in various human chronic diseases like neurodegenerative diseases and cancer, and hence is an important therapeutic target. Since, the existing inhibitors have hydroxamate group, and are not HDAC6-selective, therefore, this study has designed to investigate non-hydroxamate HDAC6 inhibitors. Ligand-based pharmacophore was generated from 26 training set compounds of HDAC6 inhibitors. The statistical parameters of pharmacophore (Hypo1) included lowest total cost of 115.63, highest cost difference of 135.00, lowest RMSD of 0.70 and the highest correlation of 0.98. The pharmacophore was validated by Fischer’s Randomization and Test Set validation, and used as screening tool for chemical databases. The screened compounds were filtered by fit value ([Formula: see text]), estimated Inhibitory Concentration (IC[Formula: see text]) ([Formula: see text]), Lipinski’s Rule of Five and Absorption, Distribution, Metabolism, Excretion, and Toxicity (ADMET) Descriptors to identify drug-like compounds. Furthermore, the drug-like compounds were docked into the active site of HDAC6. The best docked compounds were selected having goldfitness score [Formula: see text] and [Formula: see text], and hydrogen bond interaction with catalytic active residues. Finally, three inhibitors having sulfamoyl group were selected by Molecular Dynamic (MD) simulation, which showed stable root mean square deviation (RMSD) (1.6–1.9[Formula: see text]Å), lowest potential energy ([Formula: see text][Formula: see text]kJ/mol), and hydrogen bonding with catalytic active residues of HDAC6.
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BLASCHKE, D., G. BURAU, YU L. KALINOVSKY, P. MARIS, and P. C. TANDY. "FINITE T MESON CORRELATIONS AND QUARK DECONFINEMENT." International Journal of Modern Physics A 16, no. 12 (May 10, 2001): 2267–91. http://dx.doi.org/10.1142/s0217751x01003457.
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The finite temperature spatial [Formula: see text] correlation modes in the π and ρ channels are studied with the rainbow-ladder truncated quark Dyson–Schwinger equation and Bethe–Salpeter equation in the Matsubara formalism. To retain the finite range of the effective interaction while facilitating summation over fermion Matsubara modes necessary to ensure continuity at T=0, a separable kernel is used. The model is fixed by T=0 properties and it implements dynamical chiral symmetry breaking and quark confinement. Transition temperatures for deconfinement (Td) and chiral restoration (Tc) are identified. Above and below these transitions we study Mπ(T), fπ(T) and the three-space transverse and longitudinal masses [Formula: see text] and [Formula: see text]. We also study the intrinsic T-dependence of the electromagnetic coupling constant gρ(T) and the strong coupling constant gρππ(T). For both this model and a related semi-analyticinfrared dominant model, we analyze the high T behavior of the obtained masses in comparison to the M(T)→2πT behavior found in lattice QCD simulations.
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Liu, Haiqing, Na Li, Deyong Guan, and Laxmisha Rai. "Data Feature Analysis of Non-Scanning Multi Target Millimeter-Wave Radar in Traffic Flow Detection Applications." Sensors 18, no. 9 (August 21, 2018): 2756. http://dx.doi.org/10.3390/s18092756.
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The millimeter-wave radar has been widely used in traffic applications. However, little research has been done to install the millimeter-wave radar on the top of a road for detecting road traffic flow at a downward looking direction. In this paper, the vehicle parameters, including the distance, angle and radar cross-section energy, are collected by practical experiments in the aforementioned application scenario. The data features are analyzed from the dimensions of single parameter sampling characteristics and multi-parameter relationships. Further, the correlations of different parameter series are given using the grey correlation analysis method. For millimeter-wave radar used in the traffic flow detection, our work can definitely provide significant support for further intelligent transportation applications, such as vehicle trajectory tracking, traffic flow estimation and traffic event identification.
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Ji, Su-jun, Zhi-ling Ding, Hang Yin, Dao-yuan Zheng, and Jin-feng Zhao. "Theoretical study on Xe⋯N non-covalent interactions: Three hybridization N with XeO3 and XeOF2." Chinese Journal of Chemical Physics 35, no. 2 (April 2022): 322–30. http://dx.doi.org/10.1063/1674-0068/cjcp2110182.
Full textAbstract:
The interactions of complexes of XeOF2 and XeO3 with a series of different hybridization N-containing donors are studied by means of DFT and MP2 calculations. The aerogen bonding interaction energies range from 6.5 kcal/mol to 19.9 kcal/mol between XeO3 or XeOF2 and typical N-containing donors. The sequence of interaction for N-containing hybridization is sp3>sp2>sp, and XeO3 is higher than XeOF2. For some donors of sp2 and sp3 hybridization, the steric effect plays a minor role in the interaction with the evidence of reduced density gradient plots. The dominant stable part is the electrostatic interaction. In complex of XeO3, the weight of polarization is larger than dispersion, while the situation is opposite for XeOF2 complexes. Except for the sum of the maximum value of molecular electrostatic potential on Xe atom and minimum value of molecular electrostatic potential on N atom, the otherfive interaction parameters including the potential energy density at bond critical point, the equilibrium distances, interaction energies with the basis set superposition error correction, localized molecular orbital energy decomposition analysis interaction energies, and the electron charge density, show great linear correlation coefficients with each other.
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BYKHOVSKI, ALEXEI, TATIANA GLOBUS, TATYANA KHROMOVA, BORIS GELMONT, and DWIGHT WOOLARD. "AN ANALYSIS OF THE THZ FREQUENCY SIGNATURES IN THE CELLULAR COMPONENTS OF BIOLOGICAL AGENTS." International Journal of High Speed Electronics and Systems 17, no. 02 (June 2007): 225–37. http://dx.doi.org/10.1142/s012915640700445x.
Full textAbstract:
The development of an effective biological (bio) agent detection capability based upon terahertz (THz) frequency absorption spectra will require insight into how the constituent cellular components contribute to the overall THz signature. In this work, the specific contribution of ribonucleic acid (RNA) to THz spectra is analyzed in detail. Previously, it has only been possible to simulate partial fragments of the RNA (or DNA) structures due to the excessive computational demands. For the first time, the molecular structure of the entire transfer RNA (tRNA) molecule of E. coli was simulated and the associated THz signature was derived theoretically. The tRNA that binds amino acid tyrosine (tRNAtyr) was studied. Here, the molecular structure was optimized using the potential energy minimization and molecular dynamical (MD) simulations. Solvation effects (water molecules) were also included explicitly in the MD simulations. To verify that realistic molecular signatures were simulated, a parallel experimental study of tRNAs of E. coli was also conducted. Two very similar molecules, valine and tyrosine tRNA were investigated experimentally. Samples were prepared in the form of water solutions with the concentrations in the range 0.01-1 mg/ml. A strong correlation of the measured THz signatures associated with valine tRNA and tyrosine tRNA was observed. These findings are consistent with the structural similarity of the two tRNAs. The calculated THz signature of the tyrosine tRNA of E. coli reproduces many features of our measured spectra, and, therefore, provides valuable new insights into bio-agent detection.
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GRIPAIOS, B. M. "GLUON CORRELATORS IN THE KOGAN–KOVNER MODEL." International Journal of Modern Physics A 18, no. 01 (January 10, 2003): 85–95. http://dx.doi.org/10.1142/s0217751x0301228x.
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The Lorentz-invariant gluon correlation functions <F2(x) F2(x′)> and [Formula: see text], corresponding to scalar and pseudoscalar glueballs, are calculated for Kogan's and Kovner's variational ansatz for the pure SU (N) Yang–Mills wave functional. One expects only one dynamical mass scale should be present in QCD; the ansatz generates the expected scale for both glueballs, as well as an additional scale for the scalar glueball coming from the correlator of the color electric field. The additional mass scale must therefore vanish, or be close to the expected one. This is shown to constrain the nature of the phase transition in the Kogan–Kovner ansatz.
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Zainuri, Dian Alwani, Ibrahim Abdul Razak, and Suhana Arshad. "Molecular structure, DFT studies and UV–Vis absorption of two new linear fused ring chalcones: (E)-1-(anthracen-9-yl)-3-(2-methoxyphenyl)prop-2-en-1-one and (E)-1-(anthracen-9-yl)-3-(3-fluoro-4-methoxyphenyl)prop-2-en-1-one." Acta Crystallographica Section E Crystallographic Communications 74, no. 8 (July 13, 2018): 1087–92. http://dx.doi.org/10.1107/s205698901800974x.
Full textAbstract:
The title compounds, C24H18O2 and C24H17FO2, were synthesized using the Claisen–Schmidt condensation method and characterized by UV–Vis spectroscopy. Weak intermolecular C—H...O, C—H...π and π–π hydrogen-bonding interactions help to stabilize the crystal structures of both compounds. The geometrical parameters obtained from the molecular structure were optimized using density functional theory (DFT) calculations at the B3LYP/6–311++G(d,p) level, showing a good correlation with the experimental results. The small HOMO–LUMO energy gaps of 3.11 and 3.07 eV enhances the non-linear responses of these molecular systems.
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Yang, C., A. Omont, A. Beelen, Y. Gao, P. van der Werf, R. Gavazzi, Z. Y. Zhang, et al. "Molecular gas in the Herschel-selected strongly lensed submillimeter galaxies at z ~ 2–4 as probed by multi-J CO lines." Astronomy & Astrophysics 608 (December 2017): A144. http://dx.doi.org/10.1051/0004-6361/201731391.
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We present the IRAM-30 m observations of multiple-J CO (Jup mostly from 3 up to 8) and [C I](3P2 → 3P1) ([C I](2–1) hereafter) line emission in a sample of redshift ~2–4 submillimeter galaxies (SMGs). These SMGs are selected among the brightest-lensed galaxies discovered in the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS). Forty-seven CO lines and 7 [C I](2–1) lines have been detected in 15 lensed SMGs. A non-negligible effect of differential lensing is found for the CO emission lines, which could have caused significant underestimations of the linewidths, and hence of the dynamical masses. The CO spectral line energy distributions (SLEDs), peaking around Jup ~ 5–7, are found to be similar to those of the local starburst-dominated ultra-luminous infrared galaxies and of the previously studied SMGs. After correcting for lensing amplification, we derived the global properties of the bulk of molecular gas in the SMGs using non-LTE radiative transfer modelling, such as the molecular gas density nH2 ~ 102.5–104.1 cm-3 and the kinetic temperature Tk ~ 20–750 K. The gas thermal pressure Pth ranging from~105 K cm-3 to 106 K cm-3 is found to be correlated with star formation efficiency. Further decomposing the CO SLEDs into two excitation components, we find a low-excitation component with nH2 ~ 102.8–104.6 cm-3 and Tk ~ 20–30 K, which is less correlated with star formation, and a high-excitation one (nH2 ~ 102.7–104.2 cm-3, Tk ~ 60–400 K) which is tightly related to the on-going star-forming activity. Additionally, tight linear correlations between the far-infrared and CO line luminosities have been confirmed for the Jup ≥ 5 CO lines of these SMGs, implying that these CO lines are good tracers of star formation. The [C I](2–1) lines follow the tight linear correlation between the luminosities of the [C I](2–1) and the CO(1–0) line found in local starbursts, indicating that [C I] lines could serve as good total molecular gas mass tracers for high-redshift SMGs as well. The total mass of the molecular gas reservoir, (1–30) × 1010M⊙, derived based on the CO(3–2) fluxes and αCO(1–0) = 0.8 M⊙ ( K km s-1 pc2)-1, suggests a typical molecular gas depletion time tdep ~ 20–100 Myr and a gas to dust mass ratio δGDR ~ 30–100 with ~20%–60% uncertainty for the SMGs. The ratio between CO line luminosity and the dust mass L′CO/Mdust appears to be slowly increasing with redshift for high-redshift SMGs, which need to be further confirmed by a more complete SMG sample at various redshifts. Finally, through comparing the linewidth of CO and H2O lines, we find that they agree well in almost all our SMGs, confirming that the emitting regions of the CO and H2O lines are co-spatially located.
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Pazur, Richard J., D. F. R. Gilson, Pierre D. Harvey, and Ian S. Butler. "Proton spin-lattice relaxation time studies and atom–atom non-bonded potential calculations on ferrocenecarbaldehyde (η5-C5H5)Fe(η5-C5H4CHO)." Canadian Journal of Chemistry 65, no. 8 (August 1, 1987): 1940–44. http://dx.doi.org/10.1139/v87-324.
Full textAbstract:
The barriers to molecular rotations in the low temperature crystal phase of ferrocenecarbaldehyde, (η5-C5H5)Fe(η5-C5H4CHO), have been measured using proton spin-lattice relaxation methods and assigned to different motions, based on the results of non-bonded atom–atom potential calculations. The principal relaxation is interpreted in terms of a Cole–Davidson distribution of correlation times, and assigned to rotation of the unsubstituted ring, with an activation energy of 15.3 kJ mol−1. Other relaxation processes, observed via T1D measurements, include rotation of the aldehyde group and oscillations of the whole molecule, with barriers of 42.4 and 25.6 kJmol−1, respectively.
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Szczęśniak, Małgorzata M., and Steve Scheiner. "Accurate evaluation of SCF and MP2 components of interaction energies. Complexes of HF, OH2, and NH3 with Li+." Collection of Czechoslovak Chemical Communications 53, no. 10 (1988): 2214–29. http://dx.doi.org/10.1135/cccc19882214.
Full textAbstract:
High-quality Gaussian basis sets of the well-tempered type, containing three sets of polarization functions on all atoms, are used to investigate the interaction of Li+ with HF, OH2, and NH3. These sets reproduce the SCF and MP2 energies of the various monomers very well and, moreover, accurately treat the multipole moments and polarizabilities of the monomers. When applied to the complexes, the sets are essentially free of primary and secondary basis set superposition error at the SCF level; MP2 extension effects are also completely negligible while basis set superposition effects are small but non-negligible. Analysis of the correlation corrections to the molecular properties, coupled with comparison of the interaction of the bases with a point charge, provides a straightforward explanation of correlation contributions to the interaction energy. Recommendations are provided to guide selection of basis sets for molecular interactions so as to avoid distortion of the various components.
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Adinehnia, Morteza, Bryan Borders, Michael Ruf, Bhaskar Chilukuri, Ursula Mazur, and K. W. Hipps. "Structure-Function Correlation of Photoactive Ionic pi-Conjugated Binary Porphyrin Assemblies." MRS Advances 2, no. 42 (2017): 2267–73. http://dx.doi.org/10.1557/adv.2017.133.
Full textAbstract:
ABSTRACTWe present the first detailed structure-function study of a photoconducting ionic porphyrin supermolecular assembly, fabricated from tetra(N-methyl-4-pyridyl)porphyrin (TMPyP) and tetra(4-sulfonatophenyl)porphyrin (TSPP) in a 1:1 stoichiometric ratio. Rod like crystals large enough for single crystal diffraction studies were grown by utilizing a nucleation and growth model described in our previous work. The unit cell of the TMPyP:TSPP crystals is monoclinic P21/c and the cell constants are a = 8.3049(11) Å, b = 16.413(2) Å, c = 29.185(3) Å, β = 92.477(9)°. These crystals have smooth well defined facets and their internal structure consists of highly organized molecular columns of alternating porphyrin cations and anions that are stacked face to face. For the first time crystal morphology (habit) of an ionic porphyrin solid is predicted by using the crystal structure data and applying attachment energy (AE) model. The predicted habit is in good agreement with the experimental structural morphology observed in AFM and SEM images of the TMPyP:TSPP crystalline solid. The TMPyP:TSPP crystals are non-conducting in the dark and are photoconducting. The photoconductive response is significantly faster with excitation in the Q-band (Red) than with excitation in the Soret band (blue). DFT calculations were performed to determine their electronic band structure and density of states. The TMPyP:TSPP crystalline system is a useful model structure that combine the elements of molecular organization and morphology along with theory and correlate them with electronic and optical electronic properties.
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Kolesnichenko, Aleksandr Vladimirovich. "On the derivation, in the framework of the Tsallis statistics, of relativistic hydrodynamic equations for a rarefied non-ideal gas system of high-energy particles." Keldysh Institute Preprints, no. 23 (2023): 1–40. http://dx.doi.org/10.20948/prepr-2023-23.
Full textAbstract:
In the paper the construction of non-extensive relativistic dissipative hydrodynamics of identical particles on the basis of the relativistic kinetic equation obtained in a q-non-extensive context of Tsallis statistics and taking into account inclusion of correlation effects (by rejecting the molecular chaos hypothesis ) into the collision term. It is shown that the local collision equilibrium is described by a generalized version of the Yuttner relativistic distribution. With the help of this distribution all thermodynamic parameters of state are defined in explicit form. Linear constitutive relations and transport coefficients such as shear viscosity, bulk viscosity and heat conductivity are derived from the linearized collision integral written in the Anderson-Witting form and evaluated using a relaxation time approximation. The designed non-extensive relativistic fluid dynamics is designed to simulate a wide range of phenomena in astrophysics, cosmology and high-energy physics
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Cianchi, L., S. De Gennaro, F. Gulisano, M. Mancini, and G. Spina. "Occurence and correlation of two non-equivalent sites for europium in EuPd3B." Hyperfine Interactions 56, no. 1-4 (July 1990): 1437–41. http://dx.doi.org/10.1007/bf02405454.
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Verbeken, Kim, Edgar Gomes, Juergen Schneider, and Yvan Houbaert. "Correlation between the Magnetic Properties and the Crystallographic Texture during the Processing of Non Oriented Electrical Steel." Solid State Phenomena 160 (February 2010): 189–94. http://dx.doi.org/10.4028/www.scientific.net/ssp.160.189.
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The magnetic properties in electrical steels are strongly dependent on the crystallographic texture as well as other microstructural features such as grain size. Both, texture and grain size, are determined by the thermo-mechanical history of the material. This work regards a set of different thermo-mechanical paths applied on two types of non-oriented electrical steels containing 2.4% and 3.0%Si, respectively. The evolution of grain size, microstructure morphology and texture throughout processing were studied in detail by optical microscopy, X-Ray diffraction and Electron BackScatter Diffraction (EBSD). The impact of the texture on the magnetic properties was evaluated. This was done by the calculation of the magnetic anisotropy energy and the A parameter, i.e. a parameter defined in scientific literature that describes the magnetic "quality" of the texture, which can be correlated with the magnetic properties of the materials. Finally, the influence of further laser cutting on the crystallographic texture will be examined as well.
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KUPPAN, L., V. H. LIEW, and S. K. FOONG. "ON THE NON-TRIVIALITY OF THE λφ4 MODEL." International Journal of Modern Physics A 24, no. 18n19 (July 30, 2009): 3605–11. http://dx.doi.org/10.1142/s0217751x09047259.
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The λφ4 model is conventionally used to explain the origin of mass of elementary particles through the Spontaneous Symmetry Breaking (SSB) phenomena. The triviality status of the λφ4 model in 4-dimensional spacetime remains an open question despite attempts by several authors. This study establishes a new approach to determine the triviality status of the λφ4 model based on an unpublished note by Professor Bryce DeWitt. We adopted the DeWitt's Ansatz for the 2-point connected correlation function on the lattice [Formula: see text] where α is a parameter that measures the departure from triviality. Calling α's continuum counterpart as β, then a non-zero value of β signifies non-triviality of the λφ4 model. The 2-point connected correlation function, given in terms of an Euclidean functional integral, is computed numerically via Monte Carlo methods. Our analysis, based on β, is different from the traditional analysis based on the renormalized coupling constant λR. To test the new approach, we performed the simulation in 2 dimensions and obtained results that are consistent with previous findings: 2-dimensional λφ4 model is non-trivial. Finally, for the case in 4 dimensions, our results show that the model is non-trivial.
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Marco-Ahulló, Adrià, Lluïsa Montesinos-Magraner, Luis-Millán Gonzalez, Roberto Llorens, Xurxo Segura-Navarro, and Xavier García-Massó. "Validation of Using Smartphone Built-In Accelerometers to Estimate the Active Energy Expenditures of Full-Time Manual Wheelchair Users with Spinal Cord Injury." Sensors 21, no. 4 (February 22, 2021): 1498. http://dx.doi.org/10.3390/s21041498.
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This study aimed to investigate the validity of using built-in smartphone accelerometers to estimate the active energy expenditures of full-time manual wheelchair users with spinal cord injury (SCI). Twenty participants with complete SCI completed 10 5-min daily activities that involved the upper limbs, during which their oxygen consumption and upper limb activity were registered using a portable gas analyzer and a smartphone (placed on the non-dominant arm), respectively. Time series of 1-min averaged oxygen consumption and 55 accelerometer variables (13 variables for each of the four axes and three additional variables for the correlations between axes) were used to estimate three multiple linear models, using a 10-fold cross-validation method. The results showed that models that included either all variables and models or that only included the linear variables showed comparable performance, with a correlation of 0.72. Slightly worse general performance was demonstrated by the model that only included non-linear variables, although it proved to be more accurate at estimating the energy expenditures (EE) during specific tasks. These results suggest that smartphones could be a promising low-cost alternative to laboratory-grade accelerometers to estimate the energy expenditure of wheelchair users with spinal cord injury during daily activities.
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Andrews, George, Olga Neveling, Dirk Johannes De Beer, Evans M. N. Chirwa, Hendrik G. Brink, and Trudi-Heleen Joubert. "Non-Destructive Impedance Monitoring of Bacterial Metabolic Activity towards Continuous Lead Biorecovery." Sensors 22, no. 18 (September 17, 2022): 7045. http://dx.doi.org/10.3390/s22187045.
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The adverse health effects of the presence of lead in wastewater streams are well documented, with conventional methods of lead recovery and removal suffering from disadvantages such as high energy costs, the production of toxic sludge, and low lead selectivity. Klebsiella pneumoniae and Paraclostridium bifermentans have been identified as potential lead-precipitating species for use in a lead recovery bioreactor. Electrical impedance spectroscopy (EIS) on a low-cost device is used to determine the potential for the probe-free and label-free monitoring of cell growth in a bioreactor containing these bacteria. A complex polynomial is fit for several reactive equivalent circuit components. A direct correlation is found between the extracted supercapacitance and the plated colony-forming unit count during the exponential growth phase, and a qualitative correlation is found between all elements of the measured reactance outside the exponential growth phase. Strong evidence is found that Pb(II) ions act as an anaerobic respiration co-substrate for both cells observed, with changes in plated count qualitatively mirrored in the Pb(II) concentration. Guidance is given on the implementation of EIS devices for continuous impedance monitoring.
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DELFINO, G., P. GRINZA, P. MOSCONI, and G. MUSSARDO. "CORRELATION FUNCTIONS OF DISORDER OPERATORS IN MASSIVE FREE THEORIES." International Journal of Modern Physics A 19, supp02 (May 2004): 126–33. http://dx.doi.org/10.1142/s0217751x0402035x.
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A unified analysis of the disorder operators for ghosts, complex boson and fermion fields is presented. Matrix elements on the asymptotic states of these operators can be exactly computed by solving the Form Factor functional equations. The two–point correlation functions of the disorder operators depend only on the statistics and can be expressed in terms of a solution of a non–linear differential equation of Painleve' type.