Quasi-classical trajectory study of the isotope effect on the stereodynamics in the reaction H(~2S) + CH(X^2Π;u= 0,j= 1) → C(~1D) + H_2(X^1Σ_g^+)

The isotope effect on the stereodynamic properties in the title reaction is investigated by a quasi-classical trajectory （QCT） method on the 11At potential energy surface at a collision energy of 23.06 kcal/mol. The angular distributions P（φr ）, P（θr）, P（θr, φr）, and the polarization-dependent generalized differential cross sections are calculated, which demonstrate the observable influences on the rotational polarization of the product by the isotopic substitution of H with D.

Quasi-classical trajectory study of the stereodynamics of a Ne+H_2^+→NeH^++H reaction

We have carried out a quasi-classical trajectory calculation for the reaction ofNe ＋ H2＋ （v = 0, j = 1） → NeH＋ ＋ H on the ground state （12AI） using the LZHH potential energy surface constructed by L/i et al. [Lu S J, Zhang P Y, Han K L and He G Z 2010 J. Chem. Phys. 132 014303]. Differential cross sections at many collision energies indicate that the reaction is dominated by forward-scattering. In addition, the Nell＋ product shows rotationally hot and vibrationally cold distributions. Stereodynamical results indicate that the products are strongly polarized in the direction perpendicular to the scattering plane and that the products rotate mainly in planes parallel to the scattering plane.

Quasi-classical trajectory study of H+LiH（v=0,1,2,j=0）→Li+H2 reaction on a new global potential energy surface

Quasi-classical trajectory(QCT)calculations are reported for the H+LiH(v=0-2,j=0)→Li+H2 reaction on a new ground electronic state global potential energy surface(PES)of the LiH2 system.Reaction probability and integral cross sections(ICSs)are calculated for collision energies in the range of 0 eV-0.5 eV.Reasonable agreement is found in the comparison between present results and previous available theoretical results.We carried out statistical analyses with all the trajectories and found two main distinct reaction mechanisms in the collision process,in which the stripping mechanism(i.e.,without roaming process)is dominated over the collision energy range.The polarization dependent differential cross sections(PDDCSs)indicate that forward scattering dominates the reaction due to the dominated mechanism.Furthermore,the reactant vibration leads to a reduction of the reactivity because of the barrierless and attractive features of PES and mass combination of the system.

The stereodynamic properties of the F+HO(v,j) → HF+O reaction on^1 A' and ~3A' potential energy surfaces by quasi-classical trajectory calculations:Initial excitation effect(v=1-3, j=0 and v= 0, j=1-3)

The stereodynamic properties of the F ＋ HO （v, j） reaction are explored by quasi-classical trajectory （QCT） calculations performed on the 1At and 3At potential energy surfaces （PESs）. Based on the polarization-dependent differential cross sections （PDDCSs） and the angular distributions of the product angular momentum with the reactant at different values of initial v or j, the results show that the product scattering and product polarization have strong links with initial vibrationalrotational numbers of v and j. The significant manifestation of the normal DCSs is that the forward scattering gradually becomes predominant with the initial vibrational excitation increasing, and the scattering angle of the HF product taking place on the 3At potential energy surface is found to be more sensitive to the initial value of v. The product orientation and alignment are strongly dependent on the initial rovibrational excitation effect. With enhancement in the initial rovibrational excitation effect, there is an overall decrease in the product orientation as well as in the product alignment either perpendicular to the reagent relative velocity vector k or along the direction of the y axis, for which the initial rotational excitation effect is much more noticeable than the vibrational excitation effect. Moreover, the initial rovibrational excitation effect on the product polarization is more pronounced for the 3At potential energy surface than for the 1At potential energy surface.

Investigation of isotope effects of dynamic properties for H(D) + OF reactions by the quasi-classical trajectory method

Quasi-classical trajectory （QCT） calculations are employed to study the dynamic properties for H（D）＋OF reactions on the adiabatic potential energy surface （PES） of the 1^3A″ triplet state. Obvious differences between the reaction probabilities for J=0, integral cross sections for J≠0, branch ratios of the product and internuclear distances as well as product rotational alignments between the title reactions axe found. These differences are attributed mainly to the different reduced masses of the reactants and the different zero-point energies （ZPEs） of the transition state.

Quasi-classical trajectory approach to the O(~1D)+HBr→OH+Br reaction stereo-dynamics on X^1A'potential energy surface

The vector properties of reaction O（1D）＋HBr→OH＋Br on the potential energy surface （PES） of X1A＇ ground singlet state are studied by using the quasi-classical trajectory （QCT） theory. The polarization-dependent differential cross sections （PDDCSs）, the average rotational alignment factor （P 2 （j＇- k）〉, as well as the distributions reflecting vector correlations are also computed. The analysis of the results shows that the alignment and the orientation distribution of the rotation angular momentum vector of product molecule OH is influenced by both the effect of heavy-light heavy （HLH） type mass combination and the deep well of PES.

Study of the H+HS reaction on a newly built potential energy surface using the quasi-classical trajectory method

Bai Meng-Meng, Ge Mei-Hua, Yang Huan, and Zheng Yu-Jun School of Physics, Shandong University, J/nan 250100, China The quasi-classical trajectory （QCT） method is used to study the H＋HS reaction on a newly built potential energy surface （PES） of the triplet state of H2S （3AH） in a collision energy range of 0-60 kcal/mol. Both scalar properties, such as the reaction probability and the integral cross section （ICS）, and the vector properties, such as the angular distribution between the relative velocity vector of the reactant and that of the product, etc., are investigated using the QCT method. It is found that the ICSs obtained by the QCT method and the quantum mechanical （QM） method accord well with each other. In addition, the distribution for the product vibrational states is cold, while that for the product rotational states is hot for both reaction channels in the whole energy range studied here.

Quasi-Classical Trajectory Study of the Chemical Reaction Ca+CH_3I

The Ca＋CH3I→CaI＋CH3 reaction system has been studied with the quasi-classical trajectory method on the extended Lond-Eyring-Polanyi-Sato（LEPS） potential energy surface. At collision energy Ecol=10.78 kJ/mol, the calculated results show that the CaI vibrational population peaks are located at v=2. The calculated cross section decreases slowly with the collision energy increasing. The angle product distributions tend toward backward scattering. The calculated （P2（J^1·K）） values deviate slightly from-0.5 and decrease with increasing collision energy. The Quasiclassical trajectory calculation（QCT） results are in reasonable agreement with experimental data. Moreover, the dynamics of the reaction has been discussed.

Quasi-classical trajectory study of collision energy effect on the stereodynamics of H + Br O → O + HBr reaction

Quasi-classical trajectory （QCT） studies on the stereodynamics of H ＋ BrO → O＋ HBr reaction have been performed on the X1A＇ state of ab initio potential energy surface by Peterson [Peterson K A 2000 J. Chem. Phys. 113 4598] in a collision energy range from 0 kcal/mol to 6 kcal/mol. Two of the polarization-dependent generalized differential cross sections （PDDCSs）, （2π/σ）（dσ 00/d ω） （PDDCSoo） and （2π/σ）（dσ20/doh） （PDDCS20） are considered. The rotational polarizations of these products show sensitive behaviors to the calculated collision energy range. Furthermore, in order to gain more knowledge about vector correlations, the product angular distribution, P（θr）, and the dihedral angle, P （Фr）, are calculated, and the results indicate that both the rotational alignment and orientation of the product are enhanced as collision energy increases.

Dynamics of the Au+H2 reaction by time-dependent wave packet and quasi-classical trajectory methods

Dynamics of the Au + H2 reaction are studied using time-dependent wave packet(TDWP) and quasi-classical trajectory(QCT) methods based on a new potential energy surface [Int. J. Quantum Chem. 118 e25493(2018)]. The dynamic properties such as reaction probability, integral cross section, differential cross section and the distribution of product are studied at state-to-state level of theory. Furthermore, the present results are compared with the theoretical studies available.The results indicate that the complex-forming reaction mechanism is dominated in the reaction in the low collision energy region and the abstract reaction mechanism plays a dominant role at high collision energies. Different from previous theoretical calculations, the side-ways scattering signals are found in the present work and become more and more apparent with increasing collision energy.

Quasi-classical trajectory investigation on the stereodynamics of Li + DF(v=1-6,j=0)→LiF+D reaction

In this paper, the stereodynamics of Li ＋ DF → Li F ＋ D reaction is investigated by the quasi-classical trajectory（QCT）method on the ^2A＇ potential energy surface（PES） at a relatively low collision energy of 8.76 kcal/mol. The scalar properties of the title reaction such as reaction probability and cross section are studied with vibrational quantum number of v = 1–6. The product angular distributions P（θr） and P（φr） are presented in the same vibrational level range. Moreover, two polarization-dependent generalized differential cross sections（PDDCSs）, i.e., the PDDCS00 and PDDCS22＋are calculated as well. These stereodynamical results demonstrate sensitive behaviors to the vibrational quantum numbers.

Quasiclassical calculation of the chemical reaction Ba＋C3HTBr → BaBr＋C3H7

The quasi-classical trajectory （QCT） method based on the extended London-Eyring-Polanyi Sato potential en- ergy surface is used to investigate the product vibrational distribution, angular distribution and angle-resolved kinetic distribution of the reaction Ba＋C3HTBr→BaBr＋C3H7 at 2.58 kcal/mol. The calculated results show that the product BaBr vibrational distribution is quite hot, the vibrational population peaks are located at v = 12, and the angular product distribution tends to backward scattering. The calculated angle-resolved kinetic distribution shows that the kinetic distribution is obviously related to angle. The QCT results are always qualitatively acceptable and sometimes even quantitatively.

Quasi-classical trajectory approach to the stereo-dynamics of the reaction F+HO→HF+O

Quasi-classical trajectory (QCT) calculations are employed for the reaction F + HO(0,0)→HF + O based on the adiabatic potential energy surface (PES) of the ground 3A″triplet state. The average rotational alignment factor 【P2(j′·k)】 as a function of collision energy and the four polarization dependent generalized differential cross sections have been calculated in the center-of-mass (CM) frame, separately. The distribution P(θr) of the angle between k and j′, the distribution P(θr) of dihedral angle denoting k-k′-j′ correlation, and the angular distribution P(θr, Φr) of product rotational vectors in the form of polar plots are calculated as well. The effect of Heavy-Light-Heavy (HLH) mass combination and atom F’s relatively strong absorbability to charges on the alignment and the orientation of product molecule HF rotational angular momentum vectors j′ is revealed.

S(~3P)+SH(X^2Π)→S_2(X^3∑_g^-)+H(~2S)反应在新势能面上的准经典轨线研究

基于新构建的全维双多体展开势能面,运用准经典轨线方法研究了S(~3P)+SH(X^2Π)→S_2(X^3∑_g^-)+H(~2S)反应.计算得到了反应的积分截面、热速率常数、矢量相关分布以及极化微分截面.对计算结果的分析表明,随着碰撞能的增加,积分反应截面有一个下降的趋势;而随着碰撞能的增加,产物的转动极化更趋向于面内反应机制.这些结果表明产物S2对于碰撞能的变化十分敏感.

D^-+H_2反应的立体动力学研究

利用准经典轨线方法,在H3-PS势能面上研究了离子分子反应D-+H2→H-+HD的立体动力学性质.在不同碰撞能下分别计算了该反应的广义极化微分反应截面(PDDCS)、角分布P(θr),P(φr),P(θr,φr)以及产物转动取向参数<P2(j′.k)>.计算结果表明,随着碰撞能的增加,反应产物向后散射的趋势减弱,向前和侧向散射趋势增强,产物的转动角动量j′不仅具有取向而且定向于y轴负方向.对于所研究的三个碰撞能,反应产物都倾向于沿垂直散射平面的方向极化并且在平行于散射平面的平面内转动.

Influence of rotational excitation and collision energy on the stereo dynamics of the reaction:N(~4S)+H_2 (v=0,j=0,2,5,10)→NH(X^3Σ^-)+H

The N＋H2 reaction has attracted a great deal of attention from both the experimental and the theoretical community, and most of the attention has been paid to the first excited state N （2 D） atoms in collisions with hydrogen molecules and the scalar properties of the reaction. In this paper, we study the stereo dynamical properties and calculate the reaction cross sections of the N（4S） ＋ H2 （v=0, j=0, 2, 5, 10） → NH（X3∑-） ＋ H using the quasi-classical trajectory （QCT） method on an accurate NH2 potential energy surface （PES） reported by Poveda and Varandas [Poveda L A and Varandas A J C 2005 Phys. Chem. Chem. Phys. 7 28671, in a collision energy range of 25 kcal.mol-1 -140 kcal.mol-1. Results indicate that the reactant rotational excitation and initial collision energy both have a considerable influence on the distributions of the k-j＇ correlation, the k-k＇-j＇ correlation and k-k＇ correlation. The differential cross section is found to be sensitive to collision energy.

Influence of the reagent vibration on the stereodynamics of the reactions D^-+H_2 and H^-+D_2

Employing the quasi-classical trajectory method and the potential energy surface of Panda and Sathyamurhy [Panda A N and Sathyamurthy N 2004 J. Chem. Phys. 121 9343], the effect of the reagent vibration on vector correlation of the ion-molecule reactions D- ＋ H2 and H- ＋ D2 is studied at a collision energy of 35.7 kcal/mol. Four generalized polarization-dependent differential cross sections （2π/σ） （dσ00/dωt）, （2π/σ） （dσ20/dσ20）, （27π/σ） （dσ22＋/dwt）, and （2π/σ）（dπ/σ） are presented in the centre-of-mass reference frame, separately. At the same time, the effects on the product angular distributions P（θr）, P（~r） and P（Oφ） of the title reactions are also analysed. The calculated results show that the scattering tendencies of the product HD, the alignment and the orientation of j^1 sensitively depend on reagent molecule vibration.

Effect of isotope on state-to-state dynamics for reactive collision reactions O(3P)+H2^+→OH^++H and O(3P)+H2^+→OH+H^+ in ground state 1^2A" and first excited 1^2A' potential energy surfaces

We carry out quantum scattering dynamics and quasi-classical trajectory（QCT） calculations for the O+H2+ reactive collision in the ground（12 A"）.nd first excited（12 A’） potential energy surface.We calculate the reaction probabilities of O+H2+（v=0,j=0）→OH++H and O+H2+（v=0,j=0）→OH+H+reaction for total angular momentum J=0.The results calculated by QCT are consistent with those from quantum mechanical wave packet.Using the QCT method,we generate in the center-of-mass frame the product state-resolved integral cross-sections（ICSs）;two commonly used generalized polarization-dependent differential cross-sections（PDDCS s）,（2π/σ）(dσ00/dωt),（2π/σ）(dσ20/dωt));and three angular distributions of the product rotational vectors,p（θr）,P（φr）,and p（θr,φr）.We discuss the influence on the scalar and vector properties of the potential energy surface,the collision energy,and the isotope mass.Since there are deep potential wells in these two potential energy surfaces,their kinetic characteristics are similar to each other and the isotopic effect is not obvious.However,the well depths and configurations of the two potential energy surfaces are different,so the effects of isotopic substitution on the integral cross-section and the rotational polarization of product are different.

Effect of ro-vibrational excitation of NeH^+ on the stereodynamics for the reactions H+NeH^+(v=1-3,j=1,3,5) →H_2^++Ne

The stereodynamics of the abstraction reaction H^＋ NeH^＋（v = 1-3,j = 1,3,5） → H2^＋ ＋ Ne is studied theoretically with a quasi-classical trajectory method on a new ab initio potential energy surface [ S J,Zhang P Y,Han K L and He G Z 2012 J.Chem.Phys.132 014303].The effects of vibrational and rotational excitation of reagent molecules on the polarization of the product are investigated.The reaction cross sections,the distributions of P（θr）,P（φr）,and polarizationdependent differential cross sections（PDDCSs） are calculated.The obtained cross sections indicate that the title reaction is a typical barrierless atom（ion）-ion（molecule） reaction.The initial vibrational excitation and rotational excitation of reagent molecules have distinctly different influences on stereodynamics of the title reaction,and the possible reasons for the differences are presented.

The effect of collision energy on the stereodynamics of the reaction H(~2S)+NH(X^3∑^-,v = 0,j = 0)→ N(~4S)+H_2

The quasi-classical trajectory （QCT） is calculated to study the stereodynamics properties of the title reaction H（^2S） ＋ NH （X^3 ∑^-, v = 0, j = 0）→ N（^4S） ＋ H2 on the ground state ^4A″ potential energy surface （PES） constructed by Zhai and Han [2011 Jr. Chem. Phys. 135 104314]. The calculated QCT reaction probabilities and cross sections are in good agreement with the previous theoretical results. The effects of the collision energy on the k-kt distribution and the product polarization of H2 are studied in detail. It is found that the scattering direction of the product is strongly dependent on the collision energy. With the increase in the collision energy, the scattering directions of the products change from backward scattering to forward scattering. The distribution of P（Or） is strongly dependent on the collision energy below the lower collision energy （about 11.53 kcal/mol）. In addition, the P（（Pr） distribution dramatically changes as the collision energy increases. The calculated QCT results indicate that the collision energy plays an important role in determining the stereodynamics of the title reaction.