Статті в журналах: "Collision reaction"

1

ANCHISHKIN, D., V. VOVCHENKO, and S. YEZHOV. "HADRONIC REACTION ZONES IN RELATIVISTIC NUCLEUS–NUCLEUS COLLISIONS." International Journal of Modern Physics E 22, no. 06 (June 2013): 1350042. http://dx.doi.org/10.1142/s0218301313500420.

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On the basis of the proposed algorithm for calculation of the hadron reaction rates, the space-time structure of the relativistic nucleus–nucleus collisions is studied. The reaction zones and the reaction frequencies for various types of reactions are calculated for Alternating Gradient Synchrotron (AGS) and Super Proton Synchrotron (SPS) energies within the microscopic transport model. The relation of the reaction zones to the kinetic and chemical freeze-out processes is discussed. It is shown that the space-time freeze-out layer is most extended in time in the central region, while, especially for higher collision energies, the layer becomes very narrow at the sides. The parametrization of freeze-out hypersurface in the form of specific hyperbola of constant proper time was confirmed. The specific characteristic time moments of the fireball evolution are introduced. It is found that the time of the division of a reaction zone into two separate parts does not depend on the collision energy. Calculations of the hadronic reaction frequency show that the evolution of nucleus–nucleus collision can be divided into two hadronic stages.

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2

Anggara, Kelvin, Lydie Leung, Matthew J. Timm, Zhixin Hu, and John C. Polanyi. "Approaching the forbidden fruit of reaction dynamics: Aiming reagent at selected impact parameters." Science Advances 4, no. 10 (October 2018): eaau2821. http://dx.doi.org/10.1126/sciadv.aau2821.

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Collision geometry is central to reaction dynamics. An important variable in collision geometry is the miss-distance between molecules, known as the “impact parameter.” This is averaged in gas-phase molecular beam studies. By aligning molecules on a surface prior to electron-induced dissociation, we select impact parameters in subsequent inelastic collisions. Surface-collimated “projectile” molecules, difluorocarbene (CF2), were aimed at stationary “target” molecules characterized by scanning tunneling microscopy (STM), with the observed scattering interpreted by computational molecular dynamics. Selection of impact parameters showed that head-on collisions favored bimolecular reaction, whereas glancing collisions led only to momentum transfer. These collimated projectiles could be aimed at the wide variety of adsorbed targets identifiable by STM, with the selected impact parameter assisting in the identification of the collision geometry required for reaction.

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3

He, Xiaohu, Victor Wei-Keh Chao (Wu), Keli Han, Ce Hao, and Yan Zhang. "Collision time of a triatomic chemical reaction A + BC." Canadian Journal of Chemistry 93, no. 6 (June 2015): 607–14. http://dx.doi.org/10.1139/cjc-2014-0527.

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The collision time is an important quantity of an elementary chemical reaction and describes the speed of the collision process in a collision reaction. In this study, we present a generalized method to calculate the collision time of a triatomic reaction in which the collision time is defined by the sum of the incoming time, the intermediate complex time, and the outgoing time. Two variables including the total distance Rtotal and Ravg, the average value of Rtotal over time, are used to compute the three components of the collision time. We compute three triatomic reactions including Ca + HCl → CaCl + H, O + HCl → OH + Cl/OCl + H, and O + HF → OH + F at different collision energies and initial diatomic vibrational levels using the quasi-classical trajectory method to confirm that the method could be reliable and reasonable. The time evolutions of Rtotal could efficiently classify the direct and indirect reactive mechanisms and reveal a distinct discrepancy of the two mechanisms. As the collision energy and initial diatomic vibrational level increase, the percentage of direct reaction trajectories increases. At the same time, the average and maximal values of collision time decrease. Comparing the maximal collision time and the reactive probability distributions of the products, it could be found that most reactive trajectories’ collision time is less than 2 ps. Moreover, the present calculations indicate that the method could be applicable to estimate the lifetime of the intermediate complex for the reaction systems with deep potential wells and the collision time of the reactions with a direct abstraction mechanism.

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4

Gilbert, RG, and MJ McEwan. "The Pressure Dependance of Ion-Molecule Reaction Rate Coefficients: CH3+ + HCN/He." Australian Journal of Chemistry 38, no. 2 (1985): 231. http://dx.doi.org/10.1071/ch9850231.

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Illustrative calculations are presented on the application to termolecular ion-molecule reactions of methods recently developed for the study of fall-off effects in neutral thermal unimolecular reactions. The energy-dependent microscopic reaction rate, k(E), is obtained from RRKM theory with activated complex parameters first estimated by using ab initio and spectroscopic data and then refined to yield the appropriate pressure-saturated rate. The collisional energy transfer probability distribution function, P(E,E′), is obtained by fitting the fall-off data, guided by information from trajectory calculations. Overall rate coefficients are computed from accurate solutions to the appropriate integral master equation. The illustrative calculations are for the CH3+ + HCN+He → C2H4N+ +He system. It is shown that pressure-dependent data for ion-molecule systems can yield reliable information on P(E,E′). Collisions with the bath gas (He) are comparatively weak, with the average downward energy transferred per collision being c. 8 kJ mol-1. The product of the reaction before any isomerization can occur is shown to be protonated methyl isocyanide , H3CNCH+.

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5

Gilbert, RG. "Mechanism and Models for Collisional Energy Transfer in Highly Excited Large Polyatomic Molecules." Australian Journal of Chemistry 48, no. 11 (1995): 1787. http://dx.doi.org/10.1071/ch9951787.

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Collisional energy transfer in highly excited molecules (say, 200-500 kJ mol-1 above the zero-point energy of reactant, or of product, for a recombination reaction) is reviewed. An understanding of this energy transfer is important in predicting and interpreting the pressure dependence of gas-phase rate coefficients for unimolecular and recombination reactions. For many years it was thought that this pressure dependence could be calculated from a single energy-transfer quantity, such as the average energy transferred per collision. However, the discovery of 'supercollisions' (a small but significant fraction of collisions which transfer abnormally large amounts of energy) means that this simplistic approach needs some revision. The 'ordinary' (non-super) component of the distribution function for collisional energy transfer can be quantified either by empirical models (e.g., an exponential-down functional form) or by models with a physical basis, such as biased random walk (applicable to monatomic or diatomic collision partners) or ergodic (for polyatomic collision partners) treatments. The latter two models enable approximate expressions for the average energy transfer to be estimated from readily available molecular parameters. Rotational energy transfer, important for finding the pressure dependence for recombination reactions, can for these purposes usually be taken as transferring sufficient energy so that the explicit functional form is not required to predict the pressure dependence. The mechanism of 'ordinary' energy transfer seems to be dominated by low-frequency modes of the substrate, whereby there is sufficient time during a vibrational period for significant energy flow between the collision partners. Supercollisions may involve sudden energy flow as an outer atom of the substrate is squashed between the substrate and the bath gas, and then is moved away from the interaction by large-amplitude motion such as a ring vibration or a rotation; improved experimental and theoretical understanding of this phenomenon is seen as an important area for future development.

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6

ZHANG, LI, CHAO-YONG ZHU, GANG JIANG, CHAOYUAN ZHU, and Z. H. ZHU. "A QUASICLASSICAL TRAJECTORY STUDY OF REACTIVE SCATTERING ON AN ANALYTICAL POTENTIAL ENERGY SURFACE FOR GeH2 SYSTEM." Journal of Theoretical and Computational Chemistry 10, no. 02 (April 2011): 147–63. http://dx.doi.org/10.1142/s0219633611006426.

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A quasiclassical trajectory method was employed to study reaction Ge+H 2 (v=0, j=0) and reverse reaction H+GeH (v=0, j=0) on an analytical potential energy surface obtained from simplified many-body expansion method with fitting to B3P86/CC-pVTZ calculations around a global minimum and a long-range van de Waals well plus spectroscopy data for diatomic molecules GeH and H2 . Reaction probabilities from both reaction and reverse reaction were calculated. Dominant reaction is complex-forming reaction Ge+H2 (v=0, j=0) → GeH2 , and its cross section is 10 times bigger than that of complex-forming reaction from the reverse reaction. There is no threshold effect for complex-forming reaction and the cross sections for both complex-forming reactions decrease with the increase of collision energy. Life time of complex is shown to be decreasing with increase of collision energy. Dominant reverse reaction is reaction H + GeH (v=0,j=0) → Ge+H2 ; the reaction probability decreases with the increase of collision energy and differential cross section shows that this reverse reaction has almost equal angular distribution at low collision energy and mostly forward scattering at high collision energy.

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7

Blaisten-Barojas, Estela. "MOLECULAR DYNAMICS STUDY OF CLUSTER GROWTH AND POLYMER DEGRADATION." International Journal of Modern Physics B 06, no. 23n24 (December 1992): 3643–55. http://dx.doi.org/10.1142/s0217979292001705.

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This work is an overview on two molecular dynamics studies of processes at temperatures characteristic of a flame — growth of silicon clusters from binary cluster collisions and thermal degradation of polymers. In the first study, silicon clusters grow as a consequence of cluster-cluster collisions by forming transient agglomerates that coalesce in a few picoseconds. The collision energy accommodates within the cluster favoring the formation of globular larger clusters regardless of the collision energy and of the impact parameter. On the average the probability for the clusters to stick upon collision is almost 1, showing clearly that the process is irreversible. The second study concerns simple polymeric chains undergoing fragmentation when they burn. These fragments are products of thermal degradation. The consorted sequence of depolymerization reactions arises after fragmentation. As a result, a sample of degrading fragments is formed where the polymer chains have dramatically coiled. These fragments self trap themselves in coiled conformations due to the cooling effect produced by the depolymerization reaction.

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8

Dong, Yan Hua, and Xiao Jia Li. "Ab Initio Molecular Dynamics Simulations on High-Temperature Reaction Rates of Reactions KO+CO==K+CO₂, KO+C=K+CO, and K₂O+CO₂==K₂CO₃." Advanced Materials Research 875-877 (February 2014): 1037–41. http://dx.doi.org/10.4028/www.scientific.net/amr.875-877.1037.

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In this paper, we present a novel approach for calculating chemical reaction rates based on molecular collision theory, in which molecular collision cross sections are calculated by averaging over all reactive trajectories from ab initio molecular dynamics simulations. The molecular collision radius is determined by both reactive and non-reactive trajectories of molecular dynamics under constant temperature. Thus, both steric and temperature effects have been take into account for molecular collision cross sections. We have applied this approach to calculate reaction rates of reactions KO+CO==K+CO2, KO+C==K+CO, and K2O+CO2==K2CO3 under high temperature. It also shows that under higher temperature, the probabilities of a successful reaction resulting from particle collision are low, because the products are not stable.

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9

Wu, Jun-Lin, Zhi-Hui Li, Ao-Ping Peng, Xing-Cai Pi, and Xin-Yu Jiang. "Utility computable modeling of a Boltzmann model equation for bimolecular chemical reactions and numerical application." Physics of Fluids 34, no. 4 (April 2022): 046111. http://dx.doi.org/10.1063/5.0088440.

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A Boltzmann model equation (kinetic model) involving the chemical reaction of a multicomponent gaseous mixture is derived based on Groppi's work [“A Bhatnagar–Gross–Krook-type approach for chemically reacting gas mixtures,” Phys. Fluids 16, 4273 (2004)], in which the relaxation parameters of elastic collision frequency for rigid elastic spheres are obtained based on the collision term, and the pivotal collision frequency of the chemical reaction is deduced from the chemical reaction rate that is determined by the direct simulation Monte Carlo (DSMC) method. This kinetic model is shown to be conservative, and the H theorem for an endothermic reaction is proven. In the framework of the gas-kinetic unified algorithm, the discrete velocity method, finite volume method, and implicit scheme are applied to solve the proposed kinetic model by introducing a suitable boundary condition at the wall surface. For hypersonic flows around a cylinder, the proposed kinetic model and the corresponding numerical methods are verified for both endothermic and exothermic reactions by comparison of the model's results with results from the DSMC method. The different influences of endothermic and exothermic reactions are also given. Finally, the proposed kinetic model is also used to simulate an exothermic reaction-driven flow in a square cavity.

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10

Kang, Lihua, and Bin Dai. "Effect of collision energy on cross sections and product alignments for the C(1D) + H2 (v = 0, j = 0) insertion reactions." Canadian Journal of Chemistry 88, no. 5 (May 2010): 453–57. http://dx.doi.org/10.1139/v10-014.

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Quasi-classical trajectory (QCT) calculations of total reaction probabilities and vibrationally state-resolved reaction probabilities at total angular momentum J = 0 as a function of collision energy for the C(1D) + H2 (v = 0, j = 0) reactions have been performed on an ab initio potential-energy surface [ J. Chem. Phys. 2001, 115, 10701]. In addition, the integral cross sections as a function of collision energy have been carried out for the same reaction. The product rotational alignments have also been calculated, which are almost invariant with respect to collision energies.

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11

Wang, Yufeng, Jiayu Huang, Wei Wang, Tianyu Du, Yurun Xie, Yuxin Ma, Chunlei Xiao, Zhaojun Zhang, Dong H. Zhang, and Xueming Yang. "Stereodynamical control of the H + HD → H ₂ + D reaction through HD reagent alignment." Science 379, no. 6628 (January 13, 2023): 191–95. http://dx.doi.org/10.1126/science.ade7471.

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Prealigning nonpolar reacting molecules leads to large stereodynamical effects because of their weak steering interaction en route to the reaction barrier. However, experimental limitations in preparing aligned molecules efficiently have hindered the investigation of steric effects in bimolecular reactions involving hydrogen. Here, we report a high-resolution crossed-beam study of the reaction H + HD( v = 1, j = 2) → H 2 ( v ′, j ′) + D at collision energies of 0.50, 1.20, and 2.07 electron volts in which the vibrationally excited hydrogen deuteride (HD) molecules were prepared in two collision configurations, with their bond preferentially aligned parallel and perpendicular to the relative velocity of collision partners. Notable stereodynamical effects in differential cross sections were observed. Quantum dynamics calculations revealed that strong constructive interference in the perpendicular configuration plays an important role in the stereodynamical effects observed.

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12

Žabka, Ján, Zdeněk Dolejšek, Inosuke Koyano, and Zdeněk Herman. "Dynamics of Protonated Acetonitrile Formation in CD3CN+· + CH3CN Collisions: A Crossed-Beam Scattering Study." Collection of Czechoslovak Chemical Communications 63, no. 8 (1998): 1152–60. http://dx.doi.org/10.1135/cccc19981152.

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Dynamics of the elementary protonation reaction in collisions of the acetonitrile cation with acetonitrile was investigated in crossed-beam scattering experiments in the hyperthermal collision energy range 1.17-2.5 eV. The reaction proceeds by three parallel collision mechanisms: direct proton (deuteron) transfer, direct H-atom transfer, and decomposition of an intermediate complex. The relative contributions of the three mechanisms to the formation of the product at T = 2.5 eV are about equal. Analysis of product angular distributions suggests that the geometry of the critical configuration of the decomposing intermediate is prolate, not far from linear.

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13

Tachikawa, Hiroto. "SN2 and SN2′ reaction dynamics of cyclopropenyl chloride with halide ion A direct ab initio molecular dynamics (MD) study." Canadian Journal of Chemistry 83, no. 9 (September 1, 2005): 1597–605. http://dx.doi.org/10.1139/v05-176.

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Direct ab initio molecular dynamics (MD) calculations have been carried out for the reaction of cyclopropenyl chloride with halide ion (F) (F + (CH)3Cl → F(CH)3 + Cl) in gas phase. Both SN2 and SN2′ channels were found as product channels. These channels are strongly dependent on the collision angle of F to the target (CH)3Cl molecule. The collision at one of the carbon atoms of the C=C double bond leads to the SN2′ reaction channel; whereas the collision at the methylene carbon atom leads to the SN2 reaction channel. The reactions proceed via a direct mechanism without long-lived complexes. The reaction mechanism is discussed on the basis of the theoretical results.Key words: SN2 reaction, direct ab initio molecular dynamics, halogen exchange, reaction mechanism.

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14

KOWAL, M., and Z. ŁOJEWSKI. "INFLUENCE OF THE ENTRANCE CHANNEL EFFECTS ON THE FORMATION PROCESS OF SUPERHEAVY ELEMENTS." International Journal of Modern Physics E 14, no. 03 (April 2005): 327–32. http://dx.doi.org/10.1142/s0218301305003077.

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For the description of heavy-ions collisions the importance of multipole deformations of the reaction partners beyond the quadrupole deformation is investigated in particular on fusion cross sections, barrier and spin distributions. The role of fragment orientation in a collision is studied. We have applied our method to Ca – induced reactions leading to superheavy nuclei recently discovered at the Flerov Laboratory of Nuclear Reactions in Dubna. We will show that our predictions are very well confirmed by the recent experiments.

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15

Brown, Timothy L., John D. Lee, and Daniel V. McGehee. "Attention-Based Model of Driver Performance in Rear-End Collisions." Transportation Research Record: Journal of the Transportation Research Board 1724, no. 1 (January 2000): 14–20. http://dx.doi.org/10.3141/1724-03.

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Several driver-performance factors contribute to rear-end collisions—driver inattention, perception-reaction time, and limitations of the human visual system. Although many evaluations have examined driver response to various rear-end collision avoidance systems (RECAS) display and algorithm alternatives, little research has been directed at creating a quantitative model of driver performance to evaluate these alternatives. Current considerations of driver behavior in developing warning algorithms tend to ignore the fundamental problem of driver inattention and assume a fixed driver reaction time with no further adjustment after the initial response. A more refined model of driver response to rear-end crash scenarios can identify more appropriate and timely information to be displayed to the driver. An attention-based rear-end collision avoidance model (ARCAM) is introduced that describes the driver’s attention distribution, information extraction and judgment process, and the reaction process. ARCAM predicts the closed-loop nature of collision response performance and explains how the driver might use RECAS warnings.

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16

NODA, HUJIO, SHIN-ICHI NAKARIKI, and TSUTOMU TASHIRO. "MULTI-CHAIN MODEL WITH SUCCESSIVE COLLISION AND HIGH-ENERGY NUCLEUS–NUCLEUS COLLISIONS." Modern Physics Letters A 27, no. 38 (December 2, 2012): 1250219. http://dx.doi.org/10.1142/s0217732312502197.

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High-energy nucleus–nucleus collisions are studied in the multi-chain model with successive collision. Analytic forms for the longitudinal momentum distribution of the inclusive reaction are discussed. It is shown that the longitudinal momentum distribution in nucleus–nucleus collisions is expressed in the Glauber probability with the hypergeometric distribution.

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17

Finogeev, D., M. Golubeva, F. Guber, A. Ivashkin, A. Izvestny, S. Morozov, and O. Petukhov. "The Construction and Parameters of Forward Hadron Calorimeter (FHCAL) at MPD/NICA." KnE Energy 3, no. 1 (April 9, 2018): 149. http://dx.doi.org/10.18502/ken.v3i1.1737.

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Forward hadron calorimeter (FHCAL) at MPD/NICA experimental setup is intended for the measurements of the geometry of heavy ions collisions, namely, the collision centrality and the orientation of the reaction plane. FHCAL consists of two identical arms placed at the left/right sides from the beam collision point. This is a modular lead- scintillator compensating calorimeter designed to measure the energy distribution of the projectile nuclei fragments (spectators) and forward going particles close to the beam rapidity.

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18

KUMAR, V., P. LAL, H. S. PALSANIA, K. B. BHALLA, and S. LOKANATHAN. "MULTIPARTICLE PRODUCTION IN HADRON-NUCLEUS COLLISION AND THE NEGATIVE BINOMIAL DISTRIBUTION." Modern Physics Letters A 04, no. 02 (January 1989): 115–23. http://dx.doi.org/10.1142/s0217732389000162.

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Negative Binomial Distribution (NBD) has been shown to fit the charged particle multiplicity distributions obtained in various hadron-nucleus collision experiments at energies E lab = 6.2 to 800 GeV. The inverse of NBD-parameter k shows a logarithmic increase with CM energy, [Formula: see text] which is different from that in elementary collisions. It has also been shown for the abovementioned reactions that the average size of the 'clan' increases with energy. The investigation of clan structure in π− + Em reaction shows that the clans are more numerous but smaller in size in the forward than backward hemisphere.

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19

Fikov, Mihail, and Viktor Varlashin. "Investigation of the characteristics of the manipulators collision prevention system." Robotics and Technical Cybernetics 10, no. 4 (December 2022): 287–92. http://dx.doi.org/10.31776/rtcj.10407.

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The paper considers the problem of detecting and preventing collisions of manipulators with each other and with segments of the robot itself in a virtual environment. The proposed solution is to use simulator, which can simulate the physical laws of the real world with defined level of approximation, as well as methods and algorithms for collision detection in the virtual environment. Methods of representation of objects in the environment, due to which it is possible to detect collisions quickly, are considered. The collision control subsystem for the movement of two manipulators, controlled by a human operator, is simulated in the Unity environment, and its reaction speed is investigated.

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20

ZHANG, WENQIN, та MAODU CHEN. "QUASICLASSICAL TRAJECTORY STUDY OF THE STEREODYNAMICS FOR THE REACTION D+ + H2 (ν=0, j = 0) → HD + H+". Journal of Theoretical and Computational Chemistry 08, № 06 (грудень 2009): 1131–41. http://dx.doi.org/10.1142/s0219633609005465.

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The vector correlations between products and reactants for the reactive noncharge transfer ion–molecule collisions D + + H 2 (ν=0, j = 0)→ HD + H + have been determined by means of the quasiclassical trajectory method on the ground state in the KBNN potential energy surface (J Chem Phys116:654, 2002) at collision energies of 0.224, 0.524, 0.824, and 1.024 eV. The calculated differential cross section (DCS) results indicate that the lifetime of the complex [Formula: see text] in the deep well on the ground PES becomes shorter as collision energy increases. The existence of long-lived complex leads to a weak product rotational polarization at a low collision energy of 0.224 eV. However, the product rotational angular momentum j′ aligns and orients preferentially along the positive direction of the y-axis at a high collision energy of 1.024 eV. The distribution of P(θr, ϕr) indicates that the product molecules are preferentially polarized perpendicular to the scattering plane and that the reaction is dominated by an in-plane mechanism.

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21

Müller, Berndt. "Parton Cascades in High-Energy Nuclear Collisions." International Journal of Modern Physics E 12, no. 02 (April 2003): 165–76. http://dx.doi.org/10.1142/s0218301303001247.

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This is a review of the parton cascade model (PCM) which provides a QCD-based description of nucleus-nucleus reactions at very high energy. The PCM describes the collision dynamics within the early and dense phase of the reaction in terms of the relativistic, probabilistic transport of perturbative excitations (partons) of the QCD vacuum, combined with the renormalization group flow of the parton virtuality. The current state of numerical implementations of the model, as well as its predictions for nuclear collisions at RHIC and LHC are discussed.

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22

Lozano, Ana, Beatriz Pamplona, Tymon Kilich, Marta Łabuda, Mónica Mendes, João Pereira-da-Silva, Gustavo García, Pedro Gois, Filipe Ferreira da Silva, and Paulo Limão-Vieira. "The Role of Electron Transfer in the Fragmentation of Phenyl and Cyclohexyl Boronic Acids." International Journal of Molecular Sciences 20, no. 22 (November 8, 2019): 5578. http://dx.doi.org/10.3390/ijms20225578.

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In this study, novel measurements of negative ion formation in neutral potassium-neutral boronic acid collisions are reported in electron transfer experiments. The fragmentation pattern of phenylboronic acid is comprehensively investigated for a wide range of collision energies, i.e., from 10 to 1000 eV in the laboratory frame, allowing some of the most relevant dissociation channels to be probed. These studies were performed in a crossed molecular beam set up using a potassium atom as an electron donor. The negative ions formed in the collision region were mass analysed with a reflectron time-of-flight mass spectrometer. In the unimolecular decomposition of the temporary negative ion, the two most relevant yields were assigned to BO− and BO2−. Moreover, the collision-induced reaction was shown to be selective, i.e., at energies below 100 eV, it mostly formed BO−, while at energies above 100 eV, it mostly formed BO2−. In order to further our knowledge on the complex internal reaction mechanisms underlying the influence of the hybridization state of the boron atom, cyclohexylboronic acid was also investigated in the same collision energy range, where the main dissociation channel yielded BO2−. The experimental results for phenyl boronic acid are supported by ab initio theoretical calculations of the lowest unoccupied molecular orbitals (LUMOs) accessed in the collision process.

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23

YAŞAR, Mehmet. "‘O+ + N2’ ÇARPIŞMASINA AİT REAKSİYON PARAMETRELERİNİN GÜNEŞ TUTULMASINA TEPKİSİ." Euroasia Journal of Mathematics, Engineering, Natural & Medical Sciences 8, no. 17 (September 25, 2021): 178–83. http://dx.doi.org/10.38065/euroasiaorg.677.

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The ionosphere is the part of the earth's atmosphere that extends from about 75 km to 1000 km. The sun is the main factor in shaping and dividing the ionosphere according to electron density. Therefore, the investigation and examination of solar-induced events is of great importance in understanding the structure of the ionosphere. The solar eclipses are one of the most important solar-induced events that cause sudden and medium-scale changes on the ionosphere. The solar eclipse of 29 March 2006 was observed as a total eclipse in some places and as a partial eclipse in some places. One of the regions recorded as a partial eclipse is Kharkov/Ukraine. In this study, the variations of reaction dynamics such as rate constant and cross section of the ‘O+ + N2’ collision, which is one of the ionosphere reaction processes, were investigated according to altitude (187 km) and local time during the 29 March 2006 solar eclipse over the city of Kharkov. The findings revealed that the changes in the reaction rate constant were similar to the changes in temperature, but the same similarities were not observed in the collision cross-section changes. According to another result obtained from this study, it has been determined that the use of experimental-based sources such as Kharkov incoherent scatter radar will give more effective results in investigating the effects of solar eclipses on the ionosphere.

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24

Takayanagi, Kazuo. "Low-Energy Molecular Collision Processes in Space." Symposium - International Astronomical Union 120 (1987): 31–41. http://dx.doi.org/10.1017/s0074180900153756.

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Among the low-energy nonreactive molecular collisions, the rotational and vibrational transitions are the most important inelastic processes. the collision partner is an electron, an ion, or a neutral particle. Depending on the process and the collision system concerned, the magnitude and the energy dependence of the relevant cross sections are widely different. the present status of our knowledge is briefly summarized and some sample cross section data for H2and CO are shown. Useful relations among the rotational cross sections are indicated. the importance of the long-range intermolecular forces in determining some chemical reaction rates is also pointed out.

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25

Young, Alexander Baldwin, Raymond Evans March, and Richard James Hughes. "Studies of infrared multiphoton dissociation rates of protonated aliphatic alcohol dimers." Canadian Journal of Chemistry 63, no. 8 (August 1, 1985): 2324–31. http://dx.doi.org/10.1139/v85-384.

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The rates of photodissociation induced by absorption of infrared radiation of protonated dimers of 2-propanol and its deuterated analogues are reported. Protonated alcohol dimer ions created in a quadrupole ion store (QUISTOR) were irradiated in isolation and as a function of parent gas pressure and added collision gas (N2). The relative weights and nature of ionic photoproducts were determined by mass spectrometry. The effect upon photolysis of collisions both prior to and during irradiation were examined. Photodissociation rates were defined by σD, which is the measured photodissociation rate constant normalized to the laser intensity. Nascent dimer ions which can possess up to 130 kJ mol−1 internal energy dissociated readily with σD of 15.8 × 10−2 cm2 extrapolated to collision-free conditions. Photodissociation products from nascent dimer ions were produced via two major reaction channels. As the number of collisions suffered by the nascent dimer ion prior to irradiation was increased, the value of σD diminished and a single reaction channel became more prevalent. After some 270 collisions the ions appear to be collisionally relaxed prior to photolysis. The value of σD of 13.1 × 10−21 cm2 extrapolated to collision-free conditions was obtained. The products from photodissociation of relaxed ions were obtained from a single reaction channel. An increase in σD values obtained with added nitrogen collision gas indicated a blockage or "bottleneck" in multiphoton absorption which is attributed to rotational population depletion. Three deuterated analogues of 2-propanol showed similar behaviour to that of 2-propanol with the exception that deuteron-bound dimers formed from 2-propanol (OD) and perdeutero-2-propanol failed to show rotational population depletion. The apparent lack of a "bottleneck" in multiphoton absorption by deuteron bound dimers is attributed to the diminished spacings between rotational levels of these species compared with the rotational level spacings for proton-bound dimers. Proton-bound ethanol dimers were selected for the examination of temperature effects upon photodissociation rates. While values for σD, extrapolated to collision-free conditions, of 15.6 × 10−21 cm2 at 321 K (in agreement with the 2-propanol results obtained solely at this temperature) and 8.55 × 10−21 cm2 at 293 K were obtained, the precise interpretation of such a marked temperature effect is not immediately obvious.

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26

Jankunas, Justin, Richard N. Zare, Foudhil Bouakline, Stuart C. Althorpe, Diego Herráez-Aguilar, and F. Javier Aoiz. "Seemingly Anomalous Angular Distributions in H + D2 Reactive Scattering." Science 336, no. 6089 (June 28, 2012): 1687–90. http://dx.doi.org/10.1126/science.1221329.

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When a hydrogen (H) atom approaches a deuterium (D2) molecule, the minimum-energy path is for the three nuclei to line up. Consequently, nearly collinear collisions cause HD reaction products to be backscattered with low rotational excitation, whereas more glancing collisions yield sideways-scattered HD products with higher rotational excitation. Here we report that measured cross sections for the H + D2 → HD(v′ = 4, j′) + D reaction at a collision energy of 1.97 electron volts contradict this behavior. The anomalous angular distributions match closely fully quantum mechanical calculations, and for the most part quasiclassical trajectory calculations. As the energy available in product recoil is reduced, a rotational barrier to reaction cuts off contributions from glancing collisions, causing high-j′ HD products to become backward scattered.

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27

Ge, Mei Hua, Huan Yang, and Yujun Zheng. "Theoretical study of product polarization of O(1D) + HCl(v = 0; j = 0) → ClO + H and its isotope exchange reaction." Canadian Journal of Chemistry 93, no. 11 (November 2015): 1290–96. http://dx.doi.org/10.1139/cjc-2015-0288.

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O(1D) + HCl(v = 0; j = 0) → ClO + H and its isotope exchange reaction O(1D) + DCl(v = 0; j = 0) → ClO + D are studied in the collision energy range 14.0–20.0 kcal/mol based on the potential energy surface 1[Formula: see text] state. Reaction probabilities, integral cross sections, the two angular distribution functions (concerning the initial/final velocity vector, and the product rotational momentum vector), and the product rotational alignment parameters are calculated as a function of the collision energy for the two reactions. The four generalized polarization dependent differential cross sections are presented to manifest the polarization characters. Also, the effect of the collision energy and the kinetic isotope effect are studied.

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28

Eskandarian, Azim, and Ce Zhang. "A Brain Wave-Verified Driver Alert System for Vehicle Collision Avoidance." SAE International Journal of Transportation Safety 9, no. 1 (June 18, 2021): 105–22. http://dx.doi.org/10.4271/09-09-01-0002.

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Collision alert and avoidance systems (CAS) could help to minimize driver errors. They are instrumental as an advanced driver-assistance system (ADAS) when the vehicle is facing potential hazards. Developing effective ADAS/CAS, which provides alerts to the driver, requires a fundamental understanding of human sensory perception and response capabilities. This research explores the premise that external stimulation can effectively improve drivers’ reaction and response capabilities. Therefore this article proposes a light-emitting diode (LED)-based driver warning system to prevent potential collisions while evaluating novel signal processing algorithms to explore the correlation between driver brain signals and external visual stimulation. When the vehicle approaches emerging obstacles or potential hazards, an LED light box flashes to warn the driver through visual stimulation to avoid the collision through braking. Thirty (30) subjects completed a driving simulator experiment under different near-collision scenarios. The Steady-State Visually Evoked Potentials (SSVEP) of the drivers’ brain signals and their collision mitigation (control performance) data were analyzed to evaluate the LED warning system’s effectiveness. The results show that (1) The proposed modified canonical correlation analysis evaluation (CCA-EVA) algorithm can detect SSVEP responses with 4.68% higher accuracy than the Adaptive Kalman filter; (2) The proposed driver monitoring and alert system produce on average a 52% improvement in time to collision (TTC), 54% improvement in reaction distance (RD), and an overall 26% reduction in collision rate as compared to similar tests without the LED warning.

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29

Chen, Zhen, Jun Chen, Rongjun Chen, Ting Xie, Xingan Wang, Shu Liu, Guorong Wu, Dongxu Dai, Xueming Yang, and Dong H. Zhang. "Reactivity oscillation in the heavy–light–heavy Cl + CH4 reaction." Proceedings of the National Academy of Sciences 117, no. 17 (April 10, 2020): 9202–7. http://dx.doi.org/10.1073/pnas.1917618117.

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It has long been predicted that oscillatory behavior exists in reactivity as a function of collision energy for heavy–light–heavy (HLH) chemical reactions in which a light atom is transferred between two heavy atoms or groups of atoms, but direct observation of such a behavior in bimolecular reactions remains a challenge. Here we report a joint theoretical and crossed-molecular-beam study on the Cl + CH4 → HCl + CH3 reaction. A distinctive peak at a collision energy of 0.15 eV for the CH3(v = 0) product was experimentally detected in the backward scattering direction. Detailed quantum-dynamics calculations on a highly accurate potential energy surface revealed that this feature originates from the reactivity oscillation in this HLH polyatomic reaction. We anticipate that such reactivity oscillations exist in many HLH reactions involving polyatomic reagents.

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30

GAO, ZHENHAI, CHUZHAO LI, HONGYU HU, KAISHU ZHAO, HUI ZHAO, CHAOYANG CHEN, and HUILI YU. "INSTINCTUAL PHYSIOLOGICAL REACTION OF DRIVER’S CERVICAL MUSCLE TO A COLLISION." Journal of Mechanics in Medicine and Biology 15, no. 06 (December 2015): 1540044. http://dx.doi.org/10.1142/s0219519415400448.

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The influence of cervical muscles on the head/neck responses to frontal collisions is an important issue in the design of vehicle safety systems. In this study, spring-type muscles based on a Hybrid III 50th percentile dummy were used. A spring was used to simulate the cervical muscle with the instinctual physiological reaction of a driver. A total of 10 volunteers were recruited for the simulated collision tests and the maximum voluntary contraction tests, and test data were used to establish and design the spring-type muscles. Sled tests were performed using a modified dummy with spring-type muscles, which had similar mechanical characteristics to a human body. The results showed that Ax increased 3.58%, Ay decreased [Formula: see text]10.32%, Az increased 3.21%, Fx increased 12.22%, Fz increased 3.80%, and My decreased significantly ([Formula: see text]16.70% in average) at first but then increased 5.57%, in average. Cervical muscles with the instinctual physiological reaction may increase the potential head injury and potential cervical longitudinal shear injury while decreasing the potential cervical extension injury. The study provides reference for designing dummies by taking into consideration the instinctual physiological reaction of the driver to a collision.

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31

Abdelaziz, Omar, and Minzhou Luo. "Serial Robot Collision Reaction using Joints Data at Stationary Position." International journal of Engineering Works 7, no. 10 (October 16, 2020): 356–60. http://dx.doi.org/10.34259/ijew.20.710356360.

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This paper present a method for detecting collision occurs in the robot manipulator and reacting according to collision direction. An experiment was conducted to read the joints speed during collision of the UR3 robot at static position, where the joints speeds are supposed to be zero. The experiment showed that when collision occurs within the manipulator there is oscillatory speed produced in joints, which is suggested to be duo to the stiffness of the harmonic drive. The harmonic drive is a flexible transmission generates stiffness behavior, as a spring, between the motor and the link. The collision is determined from the oscillatory speed produced in robot joints at static position. The method successfully identified the collision impact at joints, and reacted according to the collision direction. The experimental setup and the results are presented in this paper.

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32

Wang, Zhimo, та Changjian Xie. "Kinetics and dynamics of the H(²S) + NO(X²Π) → N(⁴S) + OH(X²Π) Reaction: A quasi-classical trajectory study". Chinese Journal of Chemical Physics 35, № 1 (лютий 2022): 207–12. http://dx.doi.org/10.1063/1674-0068/cjcp2111262.

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A quasi-classical trajectory study of the H(2S) + NO( X2Π) → N(4S) + OH( X2Π) reaction kinetics and dynamics is reported on an accurate potential energy surface. The total integral cross sections of the reaction were calculated at the collision energy ranging from 2.00 eV to 2.80 eV. It was found that the total reaction integral cross section increases monotonically with the collision energy. Specifically at the collision energy range of 2.40–2.57 eV, our calculated results are in reasonably good agreement with the experimental data. The calculated thermal rate constants are in fairly good agreement with available experimental results. Through the trajectory analysis at the collision energy of 2.57 eV, it was found that the title reaction is dominated by the indirect trajectories (1.4 times more compared to the direct trajectories), which sheds light on the reaction dynamics of the title reaction in the high collision energy range.

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33

Chang, Yongbin, Yuping Huo, and Guoyang Yu. "The collision‐frequency and reaction rate." Physics of Fluids B: Plasma Physics 4, no. 11 (November 1992): 3621–26. http://dx.doi.org/10.1063/1.860370.

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34

De Rosa, A., E. Fioretto, G. Inglima, M. Romoli, M. Sandoli, G. Cardella, M. Papa, et al. "Reaction mechanisms in theS32+64Ni collision." Physical Review C 44, no. 2 (August 1, 1991): 747–52. http://dx.doi.org/10.1103/physrevc.44.747.

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35

Diedhiou, Malick, and Paul M. Mayer. "The Interaction of Methyl Formate with Proton-Bound Solvent Clusters in the Gas Phase and the Unimolecular Chemistry of the Reaction Products." Applied Sciences 13, no. 3 (January 19, 2023): 1339. http://dx.doi.org/10.3390/app13031339.

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Ion–molecule reactions between neutral methyl formate (MF) and proton-bound solvent clusters W2H+, W3H+, M2H+, E2H+, and E3H+ (W = water, M = methanol, and E = ethanol) showed that the major reaction product is a solvent molecule loss from the initial encounter complex, followed by the formation of protonated methyl formate (MFH+). Collision-induced dissociation breakdown curves of the initially formed solvent-MF proton-bound pairs and trimers were obtained as a function of collision energy and modeled to extract relative activation energies for the observed channels. Density functional theory calculations (B3LYP/6-311+G(d,p)) of the solvent loss reaction were consistent with barrierless reactions in each case. The MF(M)H+ ion also exhibited loss of CH4 at higher collision energies. The reaction was calculated to proceed via the migration of the MF methyl group to form a loosely bound complex between neutral CH4 and an ion comprising (CH3OH)(CO2)H+. Overall, the results indicate that the interaction of methyl formate with atmospheric water can form stable encounter complexes that will dissociate to form protonated methyl formate.

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36

Stronge, W. J. "Unraveling Paradoxical Theories for Rigid Body Collisions." Journal of Applied Mechanics 58, no. 4 (December 1, 1991): 1049–55. http://dx.doi.org/10.1115/1.2897681.

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A collision between two rigid bodies has a normal impulsive reaction at the contact point (CP). If the bodies are slightly rough and the contact points have a relative tangential velocity (slip), there is also a frictional force that opposes slip. Small initial slip can halt before contact terminates; when slip halts the frictional force changes and the collision process is separated into periods before and after halting. An energetically consistent theory for collisions with slip that halts is based on the work done by normal (nonfrictional) forces during restitution and compression phases. This theory clearly separates dissipation due to frictional forces from that due to internal irreversible deformation. With this theory, both normal and tangential components of the impulsive reaction always dissipate energy during collisions. In contrast, Newton’s impact law results in calculations of paradoxical increases in energy for collisions where slip reverses. This law relates normal components of relative velocity for the CP at separation and incidence by a constant (the coefficient of restitution e). Newton’s impact law is a kinematic definition for e that generally depends on the slip process and friction; consequently it has limited applicability.

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37

KONDOW, TAMOTSU. "REACTION PROCESSES INVOLVING GAS-PHASE CLUSTERS." Surface Review and Letters 03, no. 01 (February 1996): 631–35. http://dx.doi.org/10.1142/s0218625x96001133.

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Gas-phase clusters exhibit specific reactivities which mainly arise from their unique geometric and electronic structures, and collective vibrations due to a limited number of the constituent atoms and molecules. In order to elucidate the specificities of the reaction processes involving the clusters, we describe several examples including our studies on collisional dissociation of size-selected sodium-cluster ions with rare-gas atoms, and impact of size-selected aluminum-cluster anions and [Formula: see text] with a silicon surface. In particular, the essential features of the cluster-anion-surface collision are elucidated. A dynamic solvent effect on the dissociation of [Formula: see text] is observed in the [Formula: see text] system.

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38

Sixt, Tobias, Frank Stienkemeier, and Katrin Dulitz. "Spin-state-controlled chemi-ionization reactions between metastable helium atoms and ground-state lithium atoms." Journal of Chemical Physics 156, no. 11 (March 21, 2022): 114306. http://dx.doi.org/10.1063/5.0083842.

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We demonstrate the control of 4He(23S1)–7Li(22S1/2) chemi-ionization reactions by all-optical electron-spin-state preparation of both atomic species prior to the collision process. Our results demonstrate that chemi-ionization is strongly suppressed (enhanced) for non-spin-conserving (spin-conserving) collisions at thermal energies. These findings are in good agreement with a model based on spin angular momentum coupling of the prepared atomic states to the quasi-molecular states. Small deviations from the model indicate the contribution of the 4Σ+ channel to the reaction rate, which is in violation of spin conservation.

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39

Wang, Xin Liang, Zhe Meng, and Fan Gu. "Kinetics Analysis of Decomposing Tributylphosphate with Non-Thermal Plasma." Advanced Materials Research 875-877 (February 2014): 940–46. http://dx.doi.org/10.4028/www.scientific.net/amr.875-877.940.

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Non-thermal plasma technique can be used to degrade radioactive liquid waste involving Tributylphosphate (TBP) producing in nuclear fuel reprocessing. The dissociation reaction caused by the collision of electrons with neutral molecules can generate active radicals which play a central role in removing TBP. And the electron reacting with vapor to generate OH radicals is the key reaction in removing TBP. A model is derived from the Boltzmann equation and molecule collision theory to predicate the dissociation reaction rate coefficients. Upon comparing with available literature, the model is confirmed to be acceptably accurate in general. Reaction rate coefficients of vapor dissociation in non-thermal plasma are derived according to the Arrhenius formula.

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40

Lepers, Maxence, Grégoire Guillon, and Pascal Honvault. "Quantum mechanical study of the high-temperature H+ + HD → D+ + H2 reaction for the primordial universe chemistry." Monthly Notices of the Royal Astronomical Society 488, no. 4 (July 2, 2019): 4732–39. http://dx.doi.org/10.1093/mnras/stz1797.

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ABSTRACT We use the time-independent quantum-mechanical formulation of reactive collisions in order to investigate the state-to-state H+ + HD → D+ + H2 chemical reaction. We compute cross-sections for collision energies up to 1.8 eV and rate coefficients for temperatures up to 10 000 K. We consider HD in the lowest vibrational level v = 0 and rotational levels j = 0–6, and H2 in vibrational levels v′ = 0–3 and rotational levels j′ = 0–9. For temperatures below 4000 K, the rate coefficients strongly vary with the initial rotational level j, depending on whether the reaction is endothermic (j ≤ 2) or exothermic (j ≥ 3). The reaction is also found less and less probable as the final vibrational quantum number v′ increases. Our results illustrate the importance of studying state-to-state reactions, in the context of the chemistry of the primordial universe.

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41

Vitiuk, O. V., V. M. Pugatch, K. A. Bugaev, P. P. Panasiuk, N. S. Yakovenko, B. E. Grinyuk, E. S. Zherebtsova, et al. "Triple nuclear collisions – a new method to explore the matter properties under new extreme conditions." EPJ Web of Conferences 259 (2022): 13012. http://dx.doi.org/10.1051/epjconf/202225913012.

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We suggest to explore an entirely new method to experimentally and theoretically study the phase diagram of strongly interacting matter based on the triple nuclear collisions (TNC).We simulated the TNC using the UrQMD 3.4 model at the beam center of- mass collision energies √SNN = 200 GeV and √SNN = 2.76 TeV. It is found that in the most central and simultaneous TNC the initial baryonic charge density is about 3 times higher than the one achieved in the usual binary nuclear collisions at the same energies. As a consequence, the production of protons and Λ-hyperons is increased by a factor of 2 and 1.5, respectively. Using the MIT Bag model equation we study the evolution of the central cell in TNC and demonstrate that for the top RHIC energy of collision the baryonic chemical potential is 2-2.5 times larger than the one achieved in the binary nuclear collision at the same time of reaction. Based on these estimates, we show that TNC offers an entirely new possibility to study the QCD phase diagram at very high baryonic charge densities.

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42

ITALIANO, A., and A. STRAZZERI. "DYNAMICAL DISPERSION IN THE FAST-PARTICLE EMISSION AFTER PERIPHERAL HEAVY-ION COLLISIONS." International Journal of Modern Physics E 16, no. 01 (January 2007): 149–68. http://dx.doi.org/10.1142/s0218301307005594.

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The closed-form theoretical model, already employed to successfully describe in a single picture, the nonequilibrium component and the evaporation component of the angular correlation between particles and reaction residues emitted in a peripheral heavy-ion collision, is here revisited. This revised approach, applied to the C-α differential multiplicities for the 16O+58Ni at 6 MeV/A and 16O+48Ti at 8.3 MeV/A deep inelastic collisions, allows to explain more in detail the reaction mechanism of such processes.

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43

Kawaguchi, Satoshi. "Pulse Dynamics in a Bistable Reaction-Diffusion System with Chemotaxis." Advances in Mathematical Physics 2022 (September 12, 2022): 1–15. http://dx.doi.org/10.1155/2022/1637071.

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We consider pulse dynamics in a bistable reaction-diffusion system with chemotaxis. We derive the ordinary differential equation of interfaces by applying the multiple scales method to the reaction-diffusion system for examining the effect of the chemotaxis on pulse dynamics in one dimension. The stability of the standing pulse is considered by two different methods, and the applicability of the methods is demonstrated. The chemotaxis influences the Hopf and drift bifurcations and the collision of two traveling pulses. It also enlarges the bifurcation point and enhances the repulsive force between pulses so that the parameter region of the elastic collision becomes large. Although the ordinary differential equation of interfaces can describe the elastic collision, it cannot describe the pair annihilation of pulses caused by the collision. The conditions for the reliable calculation of pulse collision are discussed.

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44

Zhao-lin, Zhang, Liang Qi-min, Mu Yu-guang, and Xia Yue-yuan. "Collision Direction Dependence of Reaction Channels and Reaction Products in Molecular Collisions Between Two C 60 Molecules." Chinese Physics Letters 14, no. 12 (December 1997): 893–96. http://dx.doi.org/10.1088/0256-307x/14/12/004.

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45

Xia, Wen Wen, Ning Lu, Haiyang Zhong, and Li Yao. "Quasi-classical trajectory calculation of the Ba + HBr chemical reaction." Canadian Journal of Chemistry 87, no. 8 (August 2009): 1103–8. http://dx.doi.org/10.1139/v09-067.

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The results of the reaction between Ba atom and HBr are studied by using the quasi-classical trajectory (QCT) calculation on extended London–Eyring–Polanyi–Sato (LEPS) potential-energy surface (PES). The vibrational distribution, reaction cross section, and rotational alignment of the product BaBr have been calculated. The calculations predict that the reaction cross section decreases, while the translation energy and rotational energy increase with the increasing of collision energy. It has been found that low collision energy favors the abstraction reaction, whereas high collision energy leads to an insertion reaction. The calculated results agree with the experimental data and some relative theoretical results as well.

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46

Lv, Juanjuan, Xinguo Liu, Jingjuan Liang, and Haizhu Sun. "Theoretical study of the stereo-dynamics of the H + HeH+(v = 0, j = 0) → H2+ + He reaction." Canadian Journal of Physics 88, no. 12 (December 2010): 899–904. http://dx.doi.org/10.1139/p10-083.

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Theoretical study of the stereo-dynamics of the reaction, H + HeH+ (v = 0, j = 0) → H 2+ + He, have been performed with quasi-classical trajectory (QCT) method at different collision energies on a new ab initio potential energy surface. The distributions of P(θr), P(ϕr) and four generalized polarization-dependent differential cross-sections have been calculated. The results indicate that both the orientation and alignment of the rotational angular momentum are impacted by collision energies. With the collision energy increases, the rotation of the product molecule has a preference of changing from the “in-plane” reaction mechanism to the “out-of-plane” mechanism. Although the reaction is mainly dominated by the direct reaction mechanism, the indirect mechanism plays a role while the collision energy is very low.

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47

Verdasco, E., V. Saez Rabanos, and A. Gonzalez Ureña. "Reaction Dynamics of Translational and Electronic Excitation In Ca + SF6 Collisions." Laser Chemistry 10, no. 1 (January 1, 1989): 51–61. http://dx.doi.org/10.1155/1989/23523.

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Relative values of the total chemiluminescence cross.section for the crossed molecular beam Ca∗+SF6→CaF(A2Π)+SF6 reaction have been measured as a function of collision energy. Both metastable calcium atom states 3P1 were produced by low voltage de-discharge while translational excitation of the SF6 beam was achieved via the seeding technique. Whereas chemiluminescence yield from the CaF(A2Π) was observed from both of the metastable atom reactions, no chemiluminescence signal was detected from the ground atom reaction even though enough translational excitation was used to produc.e that excited product. By changing the discharge conditions different metastable concentrations were produced to measure the state-to-state cross-section for both 3P and 1D reactions, as a function of collision energy, up to 0.6 eV. Laser induced fluorescence of the atomic 4s5s 3S1←4s4p3PJ∘(J=0,1,2,3) lines have been measured to account for the metastable population in the J=1 level.

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48

XIA, WENWEN, NING LU, LI YAO, SHANSHUI GAO, KUN YANG, and HONG GAO. "QUASI-CLASSICAL TRAJECTORY CALCULATION OF THE CHEMICAL REACTION Sr + CF3Br." Journal of Theoretical and Computational Chemistry 10, no. 06 (December 2011): 819–28. http://dx.doi.org/10.1142/s0219633611006785.

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The chemical reaction dynamics between Sr atom and CF3Br has been studied by using the method of quasi-classical trajectory calculation on the London-Eyring-Polanyi-Sato potential energy surface. The vibrational distribution, reaction cross section and rotational alignment of the product SrBr have been calculated. The calculated results indicate that the cross section of this reaction decreases and the product rotational alignment increases with the increase in collision energy. It has been found that low collision energy generates the abstraction reaction whereas high collision energy leads to the insertion. The conclusions in this paper agree well with experimental data and some relative theoretical results as well.

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49

JAIN, ARUN K., and BHUSHAN N. JOSHI. "WITNESSING THE HADRONIC COLLISION EVENTS AT CLOSE QUARTERS." International Journal of Modern Physics E 18, no. 05n06 (June 2009): 1313–17. http://dx.doi.org/10.1142/s021830130901352x.

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It is seen that in the three body final state of a nucleon knockout reaction the residual nucleus not only bears testimony to the dynamics of the knocked out nucleon before the event but also can testify the happening at the time of the hard collision event. This arises mainly because of the distorting optical potentials of the residual nucleus with the knockout partners. In 40Ca(p, 2p) knockout reaction the optical distortion effects are large enough to be able to differentiate between strong peripheral bruising or the deep interpenetration of the two protons at the time of knockout. Similar effect is witnessed in the proton knockout using pions. Many stronger evidences of the effect of varying behaviour of the knockout vertex exist in the nucleon cluster knockout reactions which were only viewed as unexplained large anomalies. Evidences are provided where the different short distance behaviour of the knockout vertex t -matrix effective interaction produced huge differences in the finite range (FR) distorted wave impulse approximation (DWIA) predictions of various knockout reactions. These observations enhance the possibility of observing the multiquark objects (dibaryons, pentaquark eta.) through nucleon knockout reactions if they are produced at the knockout vertex by the incident hadron beam.

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50

FU, BINA, YONG ZHOU, and DONG H. ZHANG. "A STATE-TO-STATE QUANTUM DYNAMICAL STUDY OF THE H + HBr REACTION." Journal of Theoretical and Computational Chemistry 07, no. 04 (August 2008): 777–91. http://dx.doi.org/10.1142/s0219633608004209.

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The time-dependent wave packet method was used to calculate the state-to-state differential cross sections for abstraction and exchange processes in the title reaction on the Kurosaki–Takayanagi potential energy surface [Kurosaki Y, Takayanagi T, J Chem Phys119:7838, 2003], with the reactant HBr initially in the ground rovibrational state. It is found that the trend in the product distributions is similar for abstraction and exchange processes, but the differential cross sections are very different. For the exchange reaction, the product is mainly scattered in the backward hemisphere for collision energy up to 2.0 eV, although forward scattering gradually shows up in high collision energies. While for abstraction reaction, the differential cross section changes substantially with the collision energy, moving from predominantly backward peaked at low collision energy to predominantly forward peaked at high collision energy. The rovibrational state resolved differential cross section at collision energy of 2.0 eV exhibits two peaks for the abstraction reaction, one is around the angle of 50°, and the other at 0°. It is found that the peaks around 50°, are below the corresponding maximum j' lines provided by the kinematic constraint model, while the forward-scattered peaks straddle both sides of the kinematic limit, and are likely contributed from both the direct and the migratory reaction mechanisms as proposed by Zare and coworkers.

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