Quasi-classical Trajectory Study on the H^＋＋H2 Reaction

Quasi-classical trajectory （QCT） calculations on the H^＋＋H2 reaction system were carried out on a new potential energy surface （PES）. Theoretical calculations show that the angular distribution of the forward and backward products is roughly symmetric for the title reaction. The product rotational state distribution was also determined at a few collision energies. In t, he collision energy range from 0.124 eV to 1.424 eV, the integral cross section for this system monotonically decreases with the collision energy. A comparison with the experimental result of the ion-molecule reaction was also made, the agreement is generally good.

Quasi-classical Trajectory Study of Ba＋HI→BaI＋H Reaction

The quasi-classical trajectory calculations based on extended London-Eyring-Polanyi-Sato potential energy surface have been used to study the reaction of Ba＋HI→BaI＋H system. The rotational, vibrational, translational, and angular distributions of the product BaI have been calculated. The calculated results are in good agreement with the experimental ones.

Stereodynamics of O（^3P）＋H2 at Scattering Energies of 0.5, 0.75, and 1.0 eV

Quasiclassical trajectory calculation of the title reaction O（^3P）＋H2→OH＋H at three different scattering energies of 0.5, 0.75, and 1.0 eV on the lowest electronic potential energy surface 1^3A＂ has been done. Distribution P（θr） of polar angles between the relative velocityk of the reactant and rotational angular momentum vector j＇ of the product, distribution P（φr） of the azimuthal as well as dihedral angles correlating k-k＇-j＇, 3-dimensional distri-bution, and polarization-dependent differential cross sections （PDDCSs）dependent upon the scattering angle of the product molecule OH between the relative velocity k of the reactant and k＇ of the product at different scattering energies of 0.5, 0.75, and 1.0 eV are presented and discussed.

THE GENERAL PROPERTIES OF THE SPHERICAL VORTICES（SV）OF n－TH ORDER AND THE CHAOTIC PHENOMENA AND OF THE ORDERED STRUCTURES OF THE SV OF 3RD ORDER

The general properties of the spherical vortices(SV)of n-th order are discussedin this paper Numerical calculations are carried out in the case of n=3.We find outsome interesting phenomena concerning the chaotic regions and ordered islands on the Poincare sections. Interpretations of these phenomena are also given.

Theoretical study of stereodynamics for the reaction O(3P) ＋D2 (v=0, j=0) →OD＋D and isotope effect

Quasi-classical trajectory （QCT） calculations have been performed to study the product polarization behaviours in the reaction O（3p） ＋ D2 （v = 0, j = 0） → OD ＋ D. By running trajectories on the 3A′ and 3A″potential energy surfaces （PESs）, vector correlations such as the distributions of the polarization-dependent differential cross sections （PDDCSs）, the angular distributions of P（θr） and P（Фr） are presented. Isotope effect is discussed in this work by a comprehensive comparison with the reaction O（3p） ＋ H2 （v = 0, j = 0） → H ＋ H. Common characteristics as well as differences are discussed in product alignment and orientation for the two reactions. The isotope mass effect differs on the two potential energy surfaces： the isotope mass effect has stronger influence on P（θr） and PDDCSs of the 3A′ PES while the opposite on P（Фr） of the 3A′ potential energy surface.

Dynamics of the CH4+ O(~3 P) → CH_3(ν= 0) + OH(■= 0) reaction

The dynamics of the ground-state reaction of CH4＋ O（~3P） → CH3（ν = 0） ＋ OH（ ν= 0） have attracted a great deal of attention both theoretically and experimentally. This rapid communication represents extensive quasi-classical trajectory calculations of the vibrational distributions on a unique full-dimensional ab initio potential energy surface for the title reaction, at the collision energy of relevance to previous crossed molecular beam experiments. The surface is constructed using the all electrons coupled-cluster singles and doubles approach plus quasi-perturbative triple excitations with optimized basis sets. A modified Shepard interpolation method is also employed for the construction. Good agreement between our calculations and the available experimental results has been achieved, opening the door for accurate dynamics on this surface.

Translational,vibrational,rotational enhancements and alignments of reactions H + ClF(v = 0-5,j= 0,3,6,9) →HCl + F and HF + Cl,at E_(rel)= 0.5-20 kcal/mol

Quasi-classical trajectory calculations of the title reactions H ＋ C1F （v = 0-5, j = 0, 3,6, 9） -＋ HCl ＋ F and H ＋ C1F （v = 0-5, j =0, 3, 6, 9） → HF ＋ C1 at Erel = 0.5 kcal/mol-20 kcal/mol on ground potential energy surface DHTSN of 1 2AI [M. E Deskevich, M. Y. Hayes, K. Takahashi, R. T. Skodje and D. J. Nesbitt, J. Chem. Phys. 124, 224303 （2006）] are performed. Potential energy surfaces derived from DHTSN for the title reactions are obtained, and compared with that of DHTSN for the reaction F ＋ HC1 -＋ HF ＋ C1. Both potential energy surfaces have an early barrier pattern. Integral cross sections and alignments of product molecules HC1 and HF dependent on the internal energy states v and j of reactant molecule C1F are obtained and compared. Translational, vibrational, and rotational energy specific translational enhancements of the reactant molecule CIF of the title reactions are found. Reaction mechanisms of the title reactions according to the respective potential energy contours are further found and explained. Reasons of simultaneous translational and vibrational enhancements are clarified.

Influence of Isotope Effects on Product Polarizations of N(~2D)+D_2, N(~2D)+H_2 and N(~2D)+HD Reactive Systems

To figure out the influence of isotope effect on product polarizations of the N（2D）＋D2 reactive system and its isotope variants, quasi-classical trajectory（QCT） calculation was performed on Ho＇s potential energy surface（PES） of 2A″ state. Product polarizations such as product distributions of P（θr）, P（φr） and P（θr,φr）, as well as the generalized polarization-dependent differential cross sections（PDDCSs） were discussed and compared in detail among the four product channels of the title reactions. Both the intermolecular and intramolecular isotope effects were proved to be influential on product polarizations.

Effects of a reagent’s rotational and vibrational excitations on reaction O(~3P) + H_2 (ν=0,3,j = 0,3,5,7,9,12,15) → OH+H

To investigate the effect of a reagent＇s rotational and vibrational excitations on the stereo-dynamics of the reaction product, the title reaction is theoretically simulated using the quasi-classical trajectory （QCT） method on the 3A~ and 3Aq potentiM energy surfaces （PESs）. The reaction cross section is considered as the only scalar property in this work at four different collision energies. Furthermore the vector properties including two polarization-dependent differential cross sections （PDDCSs）, the angular distributions of product＇ rotational momentum are discussed at one fixed collision energy. Effects of reagents＇ rotational excitation on the reaction do exist regularly.

A Detailed Dynamics Study of the Reaction CH_4+Cl→HCl+CH_3

The detailed dynamics of the CH4+Cl→HCl+CH3 reaction has been investigated by means of the quasiclassical trajectory approach. The properties analyzed can be interpreted in terms of the main topological featUres of the potential energy surface used. on the basis of the theoretical results, two reaction channels are proposed: one is a direct channel and the other is a complex one.

Attitude Head Pursuit Transition Guidance Law

As an improved guidance method,the attitude head pursuit guidance （AHPG） law enables the attitude pursuit guidance （APG） law to be more suited to transition guidance of air-to-ground missiles. By adding a head angle into the attitude angle of APG,AHPG directs the missile axis onto the line of sight （LOS）. The maximum range trajectory simulation shows that the elevator deflection angle reaches the saturated value of 10° at the outset and the impact angle is less than 60° when APG is used as transi-tion guidance law. However,the elevator deflection angle on the whole trajectory is reduced to under 5° and the impact angle increased to over 60° when AHPG is used. The formulae to calculate head angles are derived for different target distributions. The simulation of multiple trajectories shows that with the help of the formulae based on AHPG law,the same performance could be achieved.

THEORETICAL STUDY OF REACTION DYNAMICS OF H_(2)■H+H ON LITHIUM(100)SURFACE

A generalized LEPS potential energy surface of (H_2?H +H)/Li(100) plane systemwas constructed based on the ab initio SCF absorption and surface diffusion of a hydrogenatom on lithium(100) surface, and reaction kinetic behaviour of this system was investigatedby means of QCT method. It was shown from analysis of the feature of this potential energysurface that the activation energy of absorption of H_2 molecules on a lithium(100) planeis unnecessary and the dissociation of H_2 on the Li(100) plane relates closely to the adsorp-tion sites and adsorption fashions, and the horizontal manner of dissociation of H_2 is easierthan the standing one. And it was also shown from the analysis of various collision trajec-tories that the surface recombination probabilities of bi-hydrogen atoms at low covering arevery small, and that the surface dissociation probabilities of H_2 are controlled by its vibra-tional quantum number. The potential energy surface of gas-metal surface interaction systemconstructed here is convenient to study on reaction dynamics, and a good explanation forcrossed molecular beam experiments of surface activation of H_2 molecule can be offered byQCT kinetic calculations in this work.