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Journal articles on the topic 'Ab initio calculations'

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Published: 4 June 2021
Last updated: 8 June 2024

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1

Lewars, Errol. "Benzooxirene. Ab initio calculations." Journal of Molecular Structure: THEOCHEM 360, no. 1-3 (January 1996): 67–80. http://dx.doi.org/10.1016/0166-1280(95)04361-6.

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2

Daub, Christopher D., Bryan R. Henry, Martin L. Sage, and Henrik G. Kjaergaard. "Article." Canadian Journal of Chemistry 77, no. 11 (November 1, 1999): 1775–81. http://dx.doi.org/10.1139/v99-151.

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Two studies of aspects of modelling dipole moment functions of XH bonds in small molecules for use in calculating overtone intensities have been undertaken. The first study deals with the fitting of ab initio calculations of the dipole moment at discrete points to a functional form. The two methods that are compared are the use of least-squares regression and the use of interpolating polynomials. The interpolating polynomial method is deemed superior due to its greater efficiency in terms of the number of points necessary to obtain reasonable results. The second study attempts to explain the indifference of calculated overtone intensities to the inclusion of electron correlation in the ab initio calculation of the dipole moment function. It is found that in most cases the influence of electron correlation can be modelled as a function with a very small matrix element, which results in a very small contribution to the overtone intensity.Key words: dipole moment function, vibrational overtone intensities, electron correlation, ab initio calculations.
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3

Frøberg, Torben, Helge Johansen, Joan Nielsen, Carsten Christophersen, Ryszard Gawinecki, Günter Häfelinger, Muhammed Nour Homsi, et al. "Ab Initio Calculations of Oxosulfatovanadates." Acta Chemica Scandinavica 50 (1996): 961–66. http://dx.doi.org/10.3891/acta.chem.scand.50-0961.

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4

Scuseria, G. E. "Ab Initio Calculations of Fullerenes." Science 271, no. 5251 (February 16, 1996): 942–45. http://dx.doi.org/10.1126/science.271.5251.942.

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5

McEachern, R. J., J. A. Weil, and P. G. Mezey. "Ab initio calculations on tetramethoxymethane." Canadian Journal of Chemistry 66, no. 8 (August 1, 1988): 2041–44. http://dx.doi.org/10.1139/v88-328.

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Minimal basis set ab initio SCF-MO calculations were performed on the 21-atom system of tetramethoxymethane (tetramethyl orthocarbonate). The geometric configuration of this model was optimized in two conformations, one having quasi-S4 symmetry and the other D2d symmetry. The S4 conformation was found to be 8 kJ mol−1 lower in energy than the D2d conformation, at the STO-3G level. The calculated energy difference is consistent with the recently measured geometric configuration of crystalline tetrabenzyl orthocarbonate. The calculated values of the bond lengths and angles were compared to the results of an electron diffraction study of the methyl species, and agree well with experiment. The theoretical electric dipole moment was calculated to be 0.01 D.
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6

Boustani, Ihsan, and Alexander Quandt. "Boron in ab initio calculations." Computational Materials Science 11, no. 2 (April 1998): 132–37. http://dx.doi.org/10.1016/s0927-0256(97)00196-1.

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7

Hinchliffe, Alan, Beatrice Nikolaidi, and Humberto Soscún Machado. "Density functional studies of the dipole polarizabilities of the linear polyacenes benzene through nonacene." Open Chemistry 3, no. 2 (June 1, 2005): 361–69. http://dx.doi.org/10.2478/bf02476002.

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AbstractWe report Ab Initio studies of the electric dipole polarizability of the linear polyacene series benzene through nonacene. A number of Ab Initio studies were done at different levels of theory for benzene, with all remaining Ab Initio calculations being at the B3LYP/6-311G(2d, 1p)//B3LYP/6-311+G(2d, 1p) level of theory. We find that the NN tensor component shows a constant increment of 20 atomic units per ring. AM1 and QSAR-quality empirical calculations show poor absolute agreement with the Ab Initio results but given excellent statistical correlation coefficients with the Ab Initio values. This implies that the results of such cheaper calculations can be suitably scaled for predictive purposes.
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8

Prakoso, Nurcahyo Iman, Lukman Hakim, and Nuri Hidayati. "Molecular Modeling of An Analog Of Curcumin Compounds Pentagamavunon-0 (PGV-0) And Pentagamavunon-1 (PGV-1) Through Computational Chemistry Methods Ab-Initio HF/4-31G." Chemical 3, no. 1 (December 31, 2017): 28–39. http://dx.doi.org/10.20885/ijcr.vol2.iss1.art4.

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Breast cancer is the second largest number of cancer cases in Indonesia, after cervical cancer. The growth of these cancer cells can be prevented with compounds Pentagamavunon-0 (PGV-0) and Pentagamavunon-1 (PGV-1). This compound is an analog of curcumin compounds that have anti breast cancer activity. Modeling the structure of compound PGV-0 and PGV-1 through computational chemistry methods Ab-initio HF/4-31G could be used to predict the geometry and structure elucidation spectra associated with pharmacological activity such as anticancer compounds theoretically.This research involves modeling the structures and spectra prediction calculation compounds PGV-0 and PGV-1 by computational chemistry methods Ab-initio HF/4-31G, using Gaussian03W. The result using Ab-initio HF/4-31G method then compared with data from experimental geometry and the results of calculations with AM1.The results showed that computational chemistry methods Ab-initio HF/4-31G calculations give better results for modeling the structure compared semiempirik method AM1.
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9

Uesugi, Tokuteru, and Kenji Higashi. "Materials Design for High-Strength Mg-Based Alloys by Understanding from Ab Initio Calculation." Materials Science Forum 488-489 (July 2005): 131–34. http://dx.doi.org/10.4028/www.scientific.net/msf.488-489.131.

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The applications of ab initio calculations for deformation mechanisms of Mg-based alloys are discussed. First, Peierls stress of pure magnesium is calculated from generalized stacking fault (GSF) energies obtained by ab initio calculations. Second, materials design is applied to develop new Mg-based alloys exhibiting high strength. The atomic size factors of some Mg-based solid solutions are calculated by ab initio calculations as a first step of searching most effective solute element for the solid-solution strengthening.
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10

Li, D. H., R. A. Moore, and S. Wang. "Variational thermodynamic calculations for some liquid sd metals." Canadian Journal of Physics 64, no. 1 (January 1, 1986): 75–83. http://dx.doi.org/10.1139/p86-011.

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A tractable and reliable expression for the one valence-electron eigenenergies, required in calculating the total energy of a disordered sd-type metal, is formulated in the context of the model-potential theory. With the aid of this expression, the variational calculation of the Helmholtz free energy using the hard-sphere model as a reference system, as employed in ab initio calculations of the thermodynamic properties for the nearly-free-electron-like (NFE) liquid metals, can now be extended with reasonable accuracy to those liquid sd metals in which the d-like valence-electron states below the Fermi level are not very localized. Also, the ab initio-type pseudopotential calculation of the interionic pair potentials, as carried out for the NFE-like metals in the literature, is made practical for these sd metals in their disordered states.
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11

Jumabaev, A. "RAMAN SPECTRA AND ab-initio CALCULATION ANALYSIS OF INTERMOLECULAR INTERACTIONS IN ETHYLACETATE." 2016-yil, 1-son (95) ANIQ VA TABIIY FANLAR SERIYASI 1, no. 95 (August 15, 2023): 1–12. http://dx.doi.org/10.59251/2181-1296.2023.v3.139.1.2085.

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Abstract. In this work the C=O vibrational band of ethylacetate was studied using Raman scattering spectra and ab-initio calculations. The obtained experiment and ab-initio calculations show that the band corresponding to the C=O stretching vibration of ethylacetate is complex and consists of several bands. ab-initio calculations were performed in the B3LYP 6-311++G (d,p) basis set, and electro-optical parameters, molecular electrostatic potential (MEP) surface, charge distribution and bond lengths of monomers and dimers of ethylacetate were determined.
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12

Popelier, Paul. "pKa prediction from ab initio calculations." Research Outreach, no. 109 (August 30, 2019): 90–93. http://dx.doi.org/10.32907/ro-109-9093.

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13

van Mourik, Tanja, Sarah L. Price, and David C. Clary. "Ab Initio Calculations on Uracil−Water." Journal of Physical Chemistry A 103, no. 11 (March 1999): 1611–18. http://dx.doi.org/10.1021/jp983337k.

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14

Binder, J., P. Zahn, and I. Mertig. "Ab initio calculations of giant magnetoresistance." Journal of Applied Physics 87, no. 9 (May 2000): 5182–84. http://dx.doi.org/10.1063/1.373288.

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15

Raabe, Gerhard, Hans-Joachim Gais, and Jörg Fleischhauer. "AB Initio Calculations on Sulfonylmethyl Anions." Phosphorus, Sulfur, and Silicon and the Related Elements 95, no. 1-4 (October 1994): 345–46. http://dx.doi.org/10.1080/10426509408034231.

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16

Reed, Lynne H., and Arthur R. Murphy. "Ab initio calculations on a microcomputer." Journal of Chemical Education 64, no. 9 (September 1987): 789. http://dx.doi.org/10.1021/ed064p789.2.

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17

Lee, B. "Ab initio calculations of lithium hydride." Journal of Molecular Structure: THEOCHEM 400, no. 1-2 (July 10, 1997): 57–68. http://dx.doi.org/10.1016/s0166-1280(97)00082-1.

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18

Lee, Belinda K., Joyce M. Stout, and Clifford E. Dykstra. "Ab initio calculations of lithium hydride." Journal of Molecular Structure: THEOCHEM 400 (July 1997): 57–68. http://dx.doi.org/10.1016/s0166-1280(97)90267-0.

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19

Alves, J. L. A., H. W. Leite Alves, C. de Oliveira, R. D. S. C. Valadão, and J. R. Leite. "Zinc-blende GaN: ab initio calculations." Materials Science and Engineering: B 50, no. 1-3 (December 1997): 57–60. http://dx.doi.org/10.1016/s0921-5107(97)00164-5.

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20

Tsui, Helen H. Y., and Tanja van Mourik. "Ab initio calculations on phenol–water." Chemical Physics Letters 350, no. 5-6 (December 2001): 565–72. http://dx.doi.org/10.1016/s0009-2614(01)01330-6.

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21

Pavone, P., R. Bauer, K. Karch, O. Schütt, S. Vent, W. Windl, D. Strauch, S. Baroni, and S. de Gironcoli. "Ab initio phonon calculations in solids." Physica B: Condensed Matter 219-220 (April 1996): 439–41. http://dx.doi.org/10.1016/0921-4526(95)00771-7.

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22

Durig, J. R., and Aiying Wang. "Ab initio calculations in vibrational spectroscopy." Journal of Molecular Structure 294 (March 1993): 13–16. http://dx.doi.org/10.1016/0022-2860(93)80303-d.

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23

Szczȩśniak, M. M., and G. Chałasiński. "Ab initio calculations of nonadditive effects." Journal of Molecular Structure: THEOCHEM 261 (July 1992): 37–54. http://dx.doi.org/10.1016/0166-1280(92)87063-6.

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24

Yuan-Sheng, Jiang, Li Xiao-Tian, Zhang Ming-Yu, and Yu Wei-Zhou. "Ab initio calculations on Fe2S2Cl2-4." Acta Chimica Sinica 5, no. 4 (November 1987): 345–48. http://dx.doi.org/10.1002/cjoc.19870050411.

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25

Pa?a-Toli?, Lj, L. Klasinc, H. Spiegl, J. V. Knop, and S. P. McGlynn. "Ab initio calculations on 5?-androstane." International Journal of Quantum Chemistry 41, no. 6 (March 20, 1992): 815–27. http://dx.doi.org/10.1002/qua.560410607.

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26

Madhavan, P. V., and J. L. Written. "Molecular symmetry in Ab initio calculations." Journal of Computational Physics 70, no. 1 (May 1987): 253–61. http://dx.doi.org/10.1016/0021-9991(87)90013-1.

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27

Tho Nguyen, Minh, M. R. Hajnal, and L. G. Vanquickenborne. "How reliable are ab initio calculations?" Journal of Molecular Structure: THEOCHEM 231 (June 1991): 185–93. http://dx.doi.org/10.1016/0166-1280(91)85216-t.

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28

Mack, Hans-Georg, and Heinz Oberhammer. "How reliable are ab initio calculations?" Journal of Molecular Structure: THEOCHEM 258, no. 1-2 (June 1992): 197–98. http://dx.doi.org/10.1016/0166-1280(92)85041-i.

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29

ZHAO, G. L., and D. BAGAYOKO. "AB-INITIO CALCULATIONS OF SUPERCONDUCTING PROPERTIES OF YBa2Cu3O7." International Journal of Modern Physics B 13, no. 29n31 (December 20, 1999): 3579–81. http://dx.doi.org/10.1142/s0217979299003465.

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We present ab-initio calculations for the electronic structure and superconducting properties of YBa 2 Cu 3 O 7 (YBCO). The electronic structure was calculated using a self-consistent ab-initio LCAO method. We solved the anisotropic Eliashberg gap equation numerically. The strong coupling of the high energy optical phonons around 60-73 meV, with the electrons at the Fermi surface, leads to a high Tc in YBCO. The calculated Tc is about 89 K for μ*=0.1. The good agreement of the calculated results with experimental measurements and the ab-initio nature of the calculations support the scenario of an anisotropic s-wave superconductor for YBCO.
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30

Чернышев, В. А., and В. П. Петров. "Фононный cпектр La-=SUB=-2-=/SUB=-Ge-=SUB=-2-=/SUB=-O-=SUB=-7-=/SUB=-: ab initio расчет." Физика твердого тела 64, no. 8 (2022): 1052. http://dx.doi.org/10.21883/ftt.2022.08.52707.301.

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Within the framework of the density functional theory ab initio calculation of the crystal structure, phonon spectrum, and elastic properties of lanthanum germanate La2Ge2O7 with a triclinic structure (sp. gr. no. 2) was carried out. The frequencies and types of fundamental modes are determined. From the analysis of the displacement vectors obtained from the calculation, the degree of participation of ions in each mode was determined. The calculations were performed for the first time. Experimental data on the IR and Raman spectra, as well as the elastic constants of La2Ge2O7, are absent in the scientific press. We used the CRYSTAL17 program designed for ab initio calculations of periodic structures within the framework of the MO LCAO approach.
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31

Kuramshina, Gulnara M., and Alexander A. Zakharov. "Stable numerical methods for determination of the molecular clusters force fields." Journal of Inverse and Ill-posed Problems 28, no. 5 (November 1, 2020): 621–31. http://dx.doi.org/10.1515/jiip-2020-0086.

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AbstractThe inverse problem of molecular force fields calculation is considered within the theory of regularization. In our strategy, we choose the stabilizing matrix F^{0} as a result of quantum mechanical calculations. The solution of the inverse problem is finding a matrix 𝐹 which is the nearest by the chosen Euclidean norm to the given ab initio F^{0}. The optimized solution is referred to as regularized quantum mechanical force field (RQMFF). Regularizing algorithms of molecular force fields calculation based on the joint treatment of experimental and ab initio quantum mechanical data have been applied to the calculations of molecular force fields (matrices of force constants) for small water clusters (H2O)𝑛 (n=2,3).
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32

Caprio, M. A., P. Maris, J. P. Vary, and R. Smith. "Collective rotation from ab initio theory." International Journal of Modern Physics E 24, no. 09 (September 2015): 1541002. http://dx.doi.org/10.1142/s0218301315410025.

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Through ab initio approaches in nuclear theory, we may now seek to quantitatively understand the wealth of nuclear collective phenomena starting from the underlying internucleon interactions. No-core configuration interaction (NCCI) calculations for p-shell nuclei give rise to rotational bands, as evidenced by rotational patterns for excitation energies, electromagnetic moments and electromagnetic transitions. In this review, NCCI calculations of 7–9 Be are used to illustrate and explore ab initio rotational structure, and the resulting predictions for rotational band properties are compared with experiment. We highlight the robustness of ab initio rotational predictions across different choices for the internucleon interaction.
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33

Mazzone, A. M. "ab initio LCAO Calculations of Small Helium Clusters." International Journal of Modern Physics C 08, no. 06 (December 1997): 1299–307. http://dx.doi.org/10.1142/s0129183197001156.

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He clusters represent an anomalous case in the field of nanosized structures owing to the extremely low value of the temperature of the liquid phase in bulk helium. The weak dissipative forces which hold these clusters together offer a severe benchmark for calculations of all types. Owing to the interest in phenomena of superfluidity and superconductivity, calculation methods, optimized from either the computational or the mathematical point of view, are the object of very intensive efforts. In this study we report calculations of the structure and energetics of small He clusters obtained by using a LCAO method of the ab initio type with simple trial functions of the gaussian type. The results indicate that the cluster structure is correctly predicted, though deep spurious minima in the energy potential surface are also found.
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34

ZHANG, D. W., and J. Z. H. ZHANG. "FULL AB INITIO COMPUTATION OF PROTEIN-WATER INTERACTION ENERGIES." Journal of Theoretical and Computational Chemistry 03, no. 01 (March 2004): 43–49. http://dx.doi.org/10.1142/s0219633604000891.

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A method to perform full quantum mechanical (ab initio) calculation of interaction energy involving a macromolecule like protein has recently been developed. This new scheme, named molecular fractionation with conjugate caps (MFCC), decomposes a protein molecule into amino acid-based fragments. These individual fragments are properly treated to preserve the chemical property of the bonds that are cut. Through proper combination of interaction energies between the molecule and individual fragments and their conjugate caps, the full protein-molecule interaction energy can be obtained to a high degree-of-accuracy by full ab initio calculations. Here we report a benchmark full ab initio calculation of interaction energy between a HIV-1 gp41 protein (with 982 atoms) and a water molecule at various geometries using HF (Hartree Fock), DFT (density functional theory) and MP2 (second-order Moller-Plesset perturbation theory) methods on a standard workstation.
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35

Kozlov S. V. and Pazyuk E. A. "Energetic and radiative properties of the A-=SUP=-2-=/SUP=-Sigma-=SUP=-+-=/SUP=--X-=SUP=-2-=/SUP=- system of the OH radical: ab initio calculation and non-adiabatic simulation." Optics and Spectroscopy 130, no. 12 (2022): 1517. http://dx.doi.org/10.21883/eos.2022.12.55236.4015-22.

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A quantum-chemical model for non-adiabatic simulation of the energetic and radiative properties of the A2Sigma+-X2 system of the OH radical is presented. The electronic structure parameters (potential energy functions and electronic matrix elements of the spin-orbit and the electron-rotation interactions) are obtained by means of ab initio calculation. The reliability of the performed calculations is confirmed by comparing ab initio estimates with experimental values for the spin-orbit splitting, the -doubling parameters of the X2 state, and the γ-doubling of the A2Sigma+ state. The frequencies and Einstein coefficients for rovibronic transitions between the A2Sigma+ and X2 states are simulated in a wide range of rovibrational excitations. The obtained values are in quantitative agreement with the data available from literature. Keywords: OH radical, ab initio calculation, non-adiabatic interaction, fine structure, radiative transition probability.
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36

Terada, Yukimasa, Tomoo Matsuura, Yukari Mori, and Shosuke Yamamura. "Theoretical studies of model compounds of lathyrane-type diterpenes." Canadian Journal of Chemistry 82, no. 1 (January 1, 2004): 11–18. http://dx.doi.org/10.1139/v03-171.

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The conformation of the 11-membered ring of the lathyrane skeleton has been investigated using NMR spectra and theoretical calculations. Some other skeletons, such as jatrophane, jatrapholane, and tigliane, seem to be derived from this framework, and the conformation is important in connection with the configuration of the resultant diterpenes. The conformation of lathyrane is principally defined by the orientation of the two methyl groups; namely, the methyl groups on C1 and C6 directed above or below the ring plane. Theoretical calculations revealed that the predominant conformation is altered depending on the oxygen functional groups on the ring. As far as the bond lengths, bond angles, and dihedral angles are concerned, all calculation methods afforded reasonable results. In contrast, as regards conformational stability, only the ab initio molecular orbital method (RHF/6-31G*) predicted the most stable conformation, consistent with NOE experiments. On the other hand, the stable conformations predicted by the ab initio method (RHF/STO-3G), the semi-empirical molecular orbital method (MOPAC(PM3)), and the molecular mechanics calculations (MM3) did not necessarily agree with the conformers suggested by the NOE experiments.Key words: ab initio MO, semi-empirical MO, molecular mechanics, 11-membered ring conformation, NOE.
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37

Sudrajat, Hanggara, Muhammad S. Saefullah, Danis Sriwijaya, Mirta A. Putri, and Ria Armunanto. "COMPUTATIONAL INVESTIGATION ON THE STRUCTURE AND NMR CHEMICAL SHIFTS OF ENDO-CONE [CS2(p-METHYLCALIX[4]ARENE)] COMPLEX." Indonesian Journal of Chemistry 9, no. 2 (June 22, 2010): 289–91. http://dx.doi.org/10.22146/ijc.21555.

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The structure and NMR chemical shifts of endo-cone [CS2(p-methylcalix[4]arene)] complex have been computationally investigated using BIO+ force fields, semi-empirical (PM3) and ab initio (RHF/6-311G++(d,p)) calculations. The first comparison of ab initio NMR chemical shift calculations for a calix[4]arene inclusion complex with solid-state 13C NMR chemical shifts based on the 1:1 complex of p-methylcalix[4]arenes with carbon disulfide in endo-cone complexation mode has been reported. The results showed that ab initio (RHF/6-311G++(d,p)) NMR calculations of the host-guest [CS2(p-methylcalix[4]arene)] complex are in good agreement with experimental solid-state NMR data. Keywords: computational investigation, structure, NMR chemical shifts, [CS2(p-methylcalix[4]arene)].
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38

Minyaev, Ruslan M., and Vladimir I. Minkin. "Theoretical study of O - > X (S, Se, Te) coordination in organic compounds." Canadian Journal of Chemistry 76, no. 6 (June 1, 1998): 776–88. http://dx.doi.org/10.1139/v98-080.

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Ab initio (RHF/LanL2DZ, MP2(fc)/LanL2DZ, MP2(fc)/6-31G**, and MP2(fc)/6-311++G**) calculations were performed for a series of β -chalcogenovinylaldehydes, 1,6-dioxa-6a-chalcogenopentalenes, and bimolecular complexes of formaldehyde with chalcogen hydrides and chlorides. The calculations reproduce well the existence and experimentally observed structural peculiarities of the intra- and intermolecular Ο - > chalcogen attractive interactions that stabilize the hypervalent T-shaped bond configuration at a chalcogen atom. These interactions increase in the order S, Se, Te and with the increasing electronegativity of a substituent attached to the chalcogen center. The ab initio calculations performed predict the existence of sufficiently stable bimolecular complexes H2CO . . .XR1R2 (X = S, Se, Te; R1, R2 = H, Cl) with a complexation energy comparable to the energy of a strong hydrogen bond.Key words: ab initio calculations, chalcogen-containing compounds, intramolecular coordination.
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39

Chernyshev V.A. and Petrov V.P. "Phonon spectrum of La-=SUB=-2-=/SUB=-Ge-=SUB=-2-=/SUB=-O-=SUB=-7-=/SUB=-: ab initio calculation." Physics of the Solid State 64, no. 8 (2022): 1065. http://dx.doi.org/10.21883/pss.2022.08.54628.301.

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Within the framework of the density functional theory ab initio calculation of the crystal structure, phonon spectrum, and elastic properties of lanthanum germanate La2Ge2O7 with a triclinic structure (sp. gr. P 1, no. 2) was carried out. The frequencies and types of fundamental modes are determined. From the analysis of the displacement vectors obtained from the calculation, the degree of participation of ions in each mode was determined. The calculations were performed for the first time. Experimental data on the IR and Raman spectra, as well as the elastic constants of La2Ge2O7, are absent in the scientific press. We used the CRYSTAL17 program designed for ab initio calculations of periodic structures within the framework of the MO LCAO approach. Keywords: rare-earth germanates, phonons, elastic constants, hybrid functionals.
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40

Krylov, Dmitry P., and Robert A. Evarestov. "Ab initio (DFT) calculations of corundum (α-Al2O3) oxygen isotope fractionation." European Journal of Mineralogy 30, no. 6 (December 20, 2018): 1063–70. http://dx.doi.org/10.1127/ejm/2018/0030-2786.

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41

SEBASTIANI, DANIEL. "AB-INITIO CALCULATIONS OF NMR PARAMETERS IN CONDENSED PHASES." Modern Physics Letters B 17, no. 25 (October 30, 2003): 1301–19. http://dx.doi.org/10.1142/s0217984903006372.

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We review the development of electronic structure methods for the calculation of nuclear magnetic resonance (NMR) properties in condensed matter over the last years. The key element is the extension of well-established approaches for the calculation of magnetic linear response to extended systems which are described under periodic boundary conditions. So far, two implementations have emerged which enable the calculation of NMR parameters within density functional theory in a pseudopotential plane wave scheme. We present the theoretical basis of the methods, further recent developments and a variety of selected applications. These applications are accompanied by comparisons with solid-state NMR experiments, exhibiting the strong impact of the symbiotic combination of high-level ab-initio calculations with experimental research.
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42

Wang, Bo-Cheng, Yun-Shan Lin, Jian-Chuang Chang, and Pei-Yu Wang. "Theoretical studies of azulene and its derivatives." Canadian Journal of Chemistry 78, no. 2 (February 6, 2000): 224–32. http://dx.doi.org/10.1139/v99-241.

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The results of ab initio calculations with the 6-31G basis sets on azulene and its derivatives (including azulenequinones and diazoazulenequinones) are presented in accordance with considerations of their structures and bonding. Azulene is a non-alternant compound with ten π electrons and has either a Cs or C2v symmetry depending on the different carbon bonding. The semiempirical and HF ab initio calculations converge to a Cs symmetry and the DFT and MP2 calculations converge to a C2v symmetry as a ground state structure of azulene. The CIS calculations describe the excited state of azulene and the first excitation energy (S0 - S1) is 533 nm (CIS/6-31+G*), which could illustrate the azure color of azulene. According to the geometry analysis, there are 16 geometrical isomers in azulenequinone conjugated diketones of azulene. Ab initio calculation with the 6-31G basis set generates 1,5- and 1,7-azulenequinone being the most stable isomers of azulenequinone. Theoretically, the relative stability of the bromination product of azulenequinones indicates that 7-bromo-1,5-azulenequinone and 3-bromo-1,7- azulenequinone (for monobromoazulenequinones) and 3,7-dibromo-1,5- azulenequinone and 3,5-dibromo-1,7-azulenequinone (for dibromoazulenequinones) are more stable isomers. The product of diazotization of amino- bromoazulenes is diazoazulenequinone in which a diazo group replaces a ketone group. Isomeric 1,8- and 1,2-diazoazulenequinones are the most stable isomers of diazoazulenequinone according to the theoretical consideration. Due to the resonance and relative stability, diazoazulenequinone may easily extrude nitrogen and form the corresponding triplet ketocarbene intermediate and electronic isomers that undergo photoreaction with THF leading to a polyether bridged azulene (crown type ether). The cyclic reactions in diazoazulenequinone are also studied.Key words: azulene, azulenequinone, diazoazulenequinone, ab initio.
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43

Hirayama, Motoaki, Ryo Okugawa, and Shuichi Murakami. "Topological Semimetals Studied by Ab Initio Calculations." Journal of the Physical Society of Japan 87, no. 4 (April 15, 2018): 041002. http://dx.doi.org/10.7566/jpsj.87.041002.

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44

Kohyama, Masanori. "Ab Initio Calculations for SiC-Al Interfaces." Materials Science Forum 207-209 (February 1996): 269–72. http://dx.doi.org/10.4028/www.scientific.net/msf.207-209.269.

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45

Bartha, F., and C. Kozmutza. "Molecular symmetry in ab initio calculations. II." Acta Physica Hungarica 58, no. 3-4 (December 1985): 227–32. http://dx.doi.org/10.1007/bf03155717.

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46

Bartha, F., E. Kapuy, and C. Kozmutza. "Molecular symmetry in ab initio calculations. I." Acta Physica Hungarica 58, no. 3-4 (December 1985): 219–25. http://dx.doi.org/10.1007/bf03155716.

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47

Bartha, F., E. Kapuy, and C. Kozmutza. "Molecular symmetry in AB initio calculations. V." Acta Physica Hungarica 59, no. 3-4 (June 1986): 347–53. http://dx.doi.org/10.1007/bf03053782.

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48

Bartha, F., E. Kapuy, C. Kozmutza, and Zs Ozoróczy. "Molecular symmetry in AB initio calculations. IV." Acta Physica Hungarica 59, no. 3-4 (June 1986): 339–46. http://dx.doi.org/10.1007/bf03053781.

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49

Bartha, F., E. Kapuy, and C. Kozmutza. "Molecular symmetry in ab initio calculations. III." Acta Physica Hungarica 59, no. 3-4 (June 1986): 333–38. http://dx.doi.org/10.1007/bf03053780.

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50

Kunes, J., and P. M. Oppeneer. "Ab Initio Calculations of Magneto-optical Effects." Transactions of the Magnetics Society of Japan 2, no. 4 (2002): 141–46. http://dx.doi.org/10.3379/tmjpn2001.2.141.

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