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.

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.

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.

Stereodynamics study of reactions N（2D）＋HD→NH＋D and ND＋H

The product polarizations of the title reactions are investigated by employing the quasi-classical trajectory （QCT） method. The four generalized polarization-dependent differential cross-sections （PDDCSs） （2π/σ）（dσ00/dωt）, （2π/σ）（dσ20/dωt）, （2π/σ）（dσ22＋/dωt）, and （2π/σ）（dσ21-/dωt） are calculated in the centre-of-mass frame. The distribution of the angle between κ and j＇, P（θr）, the distribution of the dihedral angle denoting κ-κ＇-j＇ correlation, P（Фr）, as well as the angular distribution of product rotational vectors in the form of polar plots P（θr, Фr） are calculated. The isotope effect is also revealed and primarily attributed to the difference in mass factor between the two title reactions.

Effect of the reagent vibration on stereodynamics of the reaction O（^1D）＋HF→F＋OH

This paper studies the influence of the reagent vibration on the reaction O（1D）＋HF→HO＋F by using a quasiclassical trajectory method on the new ab initio 1A＇ ground singlet potential energy surface （Gomez-Carrasco et al 2007 Chem. Phys. Lett. 435 188 193）. The product angular distributions which reflect the vector correlation are calculated. Four polarization-dependent differential cross sections （PDDCSs） which are sensitive to many photoinitiated bimolecular reaction experiments are presented in the center of the mass frame, respectively. The differential cross section indicates that the OH product mainly tends to the forward scattering, and other PDDCSs are also influenced by the vibration levels of HF.

Theoretical study of stereodynamics for reaction O（3p）＋HCl

The vector correlation between products and reagents for reaction O（3P）＋HCl→OH＋Cl is studied using a quasi- classical trajectory （QCT） method on the benchmark potential energy surface of the ground 3A″ state [Ramachandran and Peterson, J. Chem. Phys. 119 （2003） 9550]. The generalised differential cross section （2π/σ）（dσ00/dwt） is presented in the centre of mass frame. The distribution of dihedral angles, P（Фr）, and the distribution of angles between k and j′, P（θr）, are calculated. The influence of the collision energy and the influence of the reagent rotation and vibration on the product polarization are studied in the present work. The calculated results indicate that the rotational polarization of product molecule is almost independent of collision energy but sensitive to the reagent rotation and vibration. product rotational polarization, vector correlations, differential cross sections, quasi- classical trajectory

Isotope effect of the stereodynamics in the reactions F+HCl→HF+Cl and F+DCl→DF+Cl

Using a new ground-state ab initio potential energy surface reported by Deskevich et al.,the product polarizations in the reactions F+HCl→HF+Cl and F+DCl→DF+Cl were studied by employing the quasi-classical trajectory method.At a collision energy of 10 kcal/mol,the four generalized polarization-dependent differential cross-sections(2π/σ)(dσ00/dωt),(2π/σ)(dσ20/dωt),(2π/σ)(dσ22+/dωt)and(2π/σ)(dσ21-/dωt)were calculated in the center-of-mass frame.The distribution of the angle between k and j',P(θr),the distribution of the dihedral angle denoting the k-k'-j' correlation,P(φr),and the angular distribution of the product rotational vectors in the form of polar plots P(θr,φr)were also calculated.The evident influence of isotope substitution on the product polarization is revealed.This effect may result from the different mass factors of the two reactions.

反应物振动激发对反应He+H_2^+→HeH^++H影响的准经典轨线研究

基于PPA势能面(Palmieri,P.;Puzzarini,C.;Aquilanti,V.Mol.Phys.,2000,98:1835),运用准经典轨线(quasi-classical trajectory)方法,对反应He+H2+(v=0-2,j=0)→HeH++H的立体动力学性质进行了理论研究.结果表明,反应物振动激发对反应的k-j′两矢量相关和k-k′-j′三矢量相关分布都产生了较大影响.除此之外,极化微分反应截面对振动量子数v也非常敏感.

O+HCl→OH+Cl反应的立体动力学的准经典轨线研究

运用准经典轨线方法,基于Peterson从头计算势能面对O+HCl→OH+Cl反应的立体动力学性质进行了研究.讨论了在31.77和51.04 kJ/mol两种碰撞能情况下极化依赖的微分反应截面(2π/σ)(dσ00/dωt),(2π/σ)(dσ20/dωt),(2π/σ)(dσ22+/dωt)和(2π/σ)(dσ21-/dωt)以及描述k-j′两矢量相关和k-k′-j′三矢量相关的分布函数P(θr)和P(фr).计算得到的P(θr)分布表明,产物分子的转动角动量j′具有强烈的取向分布,并且产物转动角动量的取向效应对散射能的变化比较敏感.而P(фr)的分布表明,产物分子虽然具有沿着y轴的取向效应,但是没有明显的定向效应.

反应N（^2D）＋H2→NH＋H和N（^2D）＋D2→ND＋D的立体动力学理论研究

基于Ho等人的精确势能面（J．Chem．Phys．119，3063（2003））研究，运用准经典轨线方法计算了21．3kJ／mol碰撞能下反应N（^2D）＋H2→NH＋H和N（^2D）＋D2→ND＋D的产物与反应物之间的矢量相关．发现两个反应的产物角分布都是前向和后向呈现峰值分布，产物的转动角动量矢量j＇不仅是取向的，而且是在y轴负方向上定向的．两个反应显示出的同位素效应主要归因于同位素质量的差别．

低碰撞能下Li+HF(v=0－3，j=0－40)→LiF+H反应的立体动力学研究

基于2003年势能面,运用准经典轨线法(QCT)研究Li+HF→LiF+H反应立体动力学.探究较低碰撞能(1.15 kcal·mol-1-5.00 kcal·mol-1)下碰撞能、振转激发对极化微分反应截面(PDDCSs)和三矢量相关的P(θr,r)分布函数的影响,将积分散射截面与已有的理论及实验结果比较.结果显示,在较低碰撞能下碰撞能、振转激发对极化微分散射截面和三矢量相关的P(θr,r)分布函数有影响,但振转激发对极化微分反应截面和P(θr,r)分布的影响更大,碰撞能的增加使产物转动角动量后向散射的极化强度增大.在计算的能量范围内积分散射截面与其它的理论及实验结果符合较好.

反应物转动激发对反应H+HeH^+→H_2^++He立体动力学性质的影响

基于Ramachandran势能面,运用准经典轨线方法,研究了反应物转动激发对反应H+HeH+→H2++He立体动力学性质的影响。结果表明,反应物转动激发对反应的k-j′两矢量相关和k-k′-j′三矢量相关分布都产生了较大影响。产物分子H2+的转动极化在不同的转动激发态下呈现出不同的特征,而且极化微分反应截面对转动量子数j也非常敏感。

转动激发对H＋LiF→HF＋Li的立体动力学影响的理论研究

用准经典轨线方法在Aguado-Paniagua2（AP2）势能面上计算了反应物转动量子态对H＋LiF→HF＋Li反应立体动力学的影响. 给出了关于产物和反应物之间矢量相关的P（μr）和P（ár）的分布情况. 同时计算了四个极化微分反应截面. 结果表明转动量子态对H＋LiF→HF＋Li反应的矢量性质有很大影响. 还计算了H＋LiF→HF＋Li反应的反应几率.

反应物振动激发对O（3P）＋D2→OD＋D立体动力学的影响

运用准经典轨线方法，基于Roger的3A＂势能面，在碰撞能为104．5kJ／mol时对O（3P）＋D2反应的立体动力学性质进行了理论研究．详细讨论与产物矢量相关的的极化分布函数以及四个极化微分反应截面进行了．结果表明，产物OD的立体动力学性质对反应物分子H2的振动激发态量子数非常敏感．

反应物转动激发对反应O（3P）＋HCl→OH＋Cl反应的影响

基于Ramachandran B等人制作的3 A′′势能面[Ramachandran B et al 2003J.Chem.Phys.1199590],运用准经典轨线方法,计算了反应物不同振动激发态时,反应O(3P)+HCl(υ=0,1,2,j=0)→OH+Cl的P(θr),P(φr)与极化微分反应截面(2π/σ)(dσ00/dωt)、(2π/σ)(dσ22+/dωt).结果表明,反应物HCl振动激发对反应的k-j′两矢量相关和k-k′-j′三矢量相关分布都产生了较大影响.

O^+ + H_2及其同位素取代反应的立体动力学研究

运用准经典轨线方法,基于RODRIGO势能面,对碰撞能为20kcal/mol时,O++H2及其同位素取代反应的立体动力学性质进行了理论研究,对k-j′两矢量相关和k-k′-j′三矢量相关的分布函数、极化微分反应截面,以及产物转动取向参数进行了详细的讨论.结果表明,O++H2→OH++H,O++DH→OD++H和O++TH→OT++H反应的立体动力学性质对体系的质量因数非常敏感.

反应物分子初始振动激发对O+HCl→OH+Cl反应的立体动力学性质的影响

在Peterson的高精度从头计算势能面上,运用准经典轨线方法讨论了反应物分子初始振动激发对O+HCl→OH+Cl反应的立体动力学性质的影响.反映两矢量k-j′相关的P(θr)函数的分布说明产物的转动角动量j′在垂直于反应物相对速度矢量k的方向上的排列取向程度随着初始反应物振动量子数的增加而增加;反映三矢量k-k′-j′相关的极角分布函数P(r)显示产物的转动角动量有比较弱的定向效应,且随着初始振动量子数的增加,这种弱的定向效应由沿Y轴负向变为沿Y轴正向.说明反应物分子的初始振动激发有利于增强产物分子的转动排列取向效应,但对产物分子P(r)分布的影响则不明显.

用准经典轨线方法研究O（~1D）＋DBr→OD＋Br反应的极化分布

运用准经典轨线法结合Peterson从头计算势能面,在碰撞能为0.22eV时对O(1D)+DBr(v=0,j=0)→OD+Br反应进行了细致的立体动力学性质研究.极化微分反应截面(PDDCSs)给出了反应产物的散射方向.反映k与j′两矢量相关的函数P(θr)的分布表明产物分子的转动角动量j′在垂直于反应物相对速度矢量k的方向上有强烈的取向分布;反映k,k′与j′三矢量相关的函数P(θr)的分布表明产物转动角动量j′不仅有沿着y轴的取向效应,还有沿着y轴负方向的定向效应;描述产物转动角动量j′的空间分布函数P(θr,φr)说明反应垂直于散射平面极化.质量因子的不同,使得O(1D)+DBr反应的极化与O(1D)+HBr反应的极化有明显的差异,说明同位素效应比较明显.

Li+HF(v=0—3,j=0)→LiF+H反应的立体动力学理论研究

基于2003年Alfredo Aguado等人构造的新势能面(Aguado和Paniagua.J.Chem.Phys.,Vol.119,No.19,2003),本文结合振动激发和碰撞能两个因素,采用准经典轨线的方法对反应Li+HF(v=0—3)的k-j′两矢量相关和k-k′-j′三矢量相关的分布函数及极化微分反应截面进行了详细的立体动力学研究.结果表明,描述三原子分子反应的k-j′两矢量相关联的函数P(θr)分布不受振动激发影响,而碰撞能则对其影响较大.描述k-k′-j′三矢量相关的函数P(r)分布和极化微分反应截面对振动激发较敏感,同时我们发现碰撞能对P(Фr)分布和极化微分反应截面也有较大影响.

碰撞能及反应物振动激发对Ar+H_2^+→ArH^++H反应立体动力学性质的影响

基于我们最近所构建的Ar+H+2→ArH++H(12A′)反应的新势能面,采用准经典轨线法研究了碰撞能分别为0.48,0.77,1.24 eV以及能量为0.48 eV时反应物不同振动态下Ar+H+2→ArH++H反应的立体动力学性质.结果显示在给定的碰撞能情况下,以及当反应物振动量子数由0变到2时计算的积分反应截面与实验值符合得较好.通过比较发现,碰撞能对此反应k-j′关联函数P(θr)分布的影响大于其受振动激发的影响,并且关于k-k′-j′三矢量相关的函数P(?r)分布以及极化微分反应截面对碰撞能较敏感,同时发现振动激发对P(?r)分布和极化微分反应截面也有较大的影响.