Effect of reagent vibrational excitation and isotope substitution on the stereo-dynamics of the Ba+HF→BaF+H reaction

Based on an extended London-Eyring-Polanyi-Sato (LEPS) potential energy surface (PES),the Ba + HF reaction has been studied by the quasi-classical trajectory (QCT) method. The reaction integral cross section as a function of collision energy for the Ba + HF → BaF + H reaction is presented and the influence of isotope substitution on the differential cross sections (DCSs) and alignments of the product’s rotational angular momentum have also been studied. The results suggest that the integral cross sections increase with increasing collision energy,and the vibrational excitation of the reagent has great influence on the DCS. In addition,the product’s rotational polarization is very strong as a result of heavy-heavy-light (HHL) mass combination,and the distinct effect of isotope substitution on the stereodynamics is also revealed.     

Effects of the vibrational and rotational excitation of reagent on the stereodynamics of the reaction S（3P） + H2→ SH + H

Quasiclassical trajectory （QCT） calculations are first carried out to study the stereodynamics of the S （3p） ＋ H2 → SH ＋ H reaction based on the ab initio 13Atr potential energy surface （PES） （Lii etal. 2012 J. Chem. Phys. 136 094308）. The QCT-calculated reaction probabilities and cross sections for the S ＋ H2 （v = 0, j = 0） reaction are in good agreement with the previous quantum mechanics （QM） results. The vector properties including the alignment, orientation, and polarization- dependent differential cross sections （PDDCSs） of the product SH are presented at a collision energy of 1.8 eV. The effects of the vibrational and rotational excitations of reagent on the stereodynamics are also investigated and discussed in the present work. The calculated QCT results indicate that the vibrational and rotational excitations of reagent play an important role in determining the stereodynamic properties of the title reaction.     

Influence of reagent vibration on the stereodynamics of the Li ＋ HF → LiF ＋ H reaction

We investigate the influence of reagent vibration on the stereodynamics of the title reaction by the quasi-classical trajectory on the Aguado-Paniagua2-potential energy surface developed by Aguado et al.(J.Chem.Phys.1997 106 1013).The cross sections and reaction probability as functions of the reagent vibration are calculated in the centre-ofmass frame.The product angular distributions of p(θr),p(φr),and p(θr,φr),which reflect the vector correlation,are also presented and discussed.The results indicate that the vector properties are sensitively affected by the vibrational excitation.     

A theoretical study of the stereodynamics on the abstraction reactions H/D ＋ HS/DS

The quasi-classical trajectory(QCT) method is employed to calculate the stereodynamics of the abstraction reactions H/D+HS/DS based on an accurate potential energy surface [L S J,Zhang P Y,Han K L and He G Z 2012 J.Chem.Phys.136 094308].The reaction cross sections of the title reaction are computed,and the vector correlations for different collision energies and different initial vibrational states are presented.The influences of the collision energy and reagent vibration on the product polarization are studied,and the product polarizations of the title reactions are found to be distinctly different,which arises from the different mass factors,collision energies,and reagent vibrational states.     

Effects of a reagent＇s rotational and vibrational excitations on reactionO（3p）＋ H2（v=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 3 A and 3 A potential 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.     

Effect of Reagent Vibrational and Rotational Excitation on the F＋H2 Reaction： Theoretical Study of the Stereodynamics Using Quasi-Classical Trajectory Method

The vector correlations in the reaction F＋H2 （v =0-3, j =0-3）→ HF（v＇, j＇）＋H are investigated using the quasi- classical trajectory method on the Stark-Werner potential energy surface at a collision energy of 1.0eV. The potential distribution P（θr） to angles between k and j＇, the distribution P（Фr） to dihedral angles, denoting k - k＇ - j＇ correlation and the polarization-dependent generalized differential cross sections, are calculated. The effect of reagent vibrational and rotational excitation on the F＋H2 reaction is discussed in detail The results suggest that the different vibrational and rotational quantum states of H2 have different influences on the product polarization.     

Vector correlations study of the reaction N(~2D) + H_2(X~1Σ_g~+) →NH(a~1?) + H(~2S) with different collision energies and reagent vibration excitations

Vector correlations of the reaction N(2D)+ H2(X1Σ+g) → NH(a1?)+ H(2S) are studied based on a recent DMBESEC PES for the first excited state of NH2[J. Phys. Chem. A 114 9644(2010)] by using a quasi-classical trajectory method.The effects of collision energy and the reagent initial vibrational excitation on cross section and product polarization are investigated for v = 0–5 and j = 0 states in a wide collision energy range(10–50 kcal/mol). The integral cross section could be increased by H2 vibration excitation remarkably based on the DMBE-SEC PES. The different phenomena of differential cross sections with different collision energies and reagent vibration excitations are explained. Particularly,the NH molecules are scattered mainly in the backward hemisphere at low vibration quantum number and evolve from backward to forward direction with increasing vibration quantum number, which could be explained by the fact that the vibrational excitation enlarges the H–H distance in the entrance channel, thus enhancing the probability of collision between N atom and H atom. A further study on product polarization demonstrates that the collision energy and vibrational excitation of the reagent remarkably influence the distributions of P(θr), P(φr), and P(θr, φr).     

Isotope effect on the stereodynamics for the collision reaction H＋LiF（v = 0, j = 0） → HF＋Li

Stereodynamics for the reaction H+LiF(v=0, j=0) → HF+Li and its isotopic variants on the ground-state (1 2 A′) potential energy surface (PES) are studied by employing the quasi-classical trajectory (QCT) method. At a collision energy of 1.0 eV, product rotational angular momentum distributions P (θr), P (φr), and P (θr ,φr), are calculated in the center-of-mass (CM) frame. The results demonstrate that the product rotational angular momentum j′ is not only aligned along the direction perpendicular to the reagent relative velocity vector k, but also oriented along the negative y axis. The four generalized polarization-dependent differential cross sections (PDDCSs) are also computed. The PDDCS 00 distribution shows a preferential forward scattering for the product angular distribution in each of the three isotopic reactions, which indicates that the title collision reaction is a direct reaction mechanism. The isotope effect on the stereodynamics is revealed and discussed in detail.     

The reagent vibrational excitation effect on the stereodynamics of the reaction O(~1D)+HBr→OH+Br

Calculations on the dynamics of the reaction O( 1 D) + HBr → OH + Br are performed on the ab initio potential energy surfaces (PESs) of the ground state given by Peterson Peterson K A J. Chem. Phys. 113 4598 (2000)using the quasiclassical trajectory (QCT) method. The product distribution of the dihedral angle, P (φ r ), and that of the angle between and , P (θ r ), are presented in three dimensions. Moreover, we also investigate the reagent vibrational excitation effects on the two polarization-dependent generalized differential cross sections (PDDCS), PDDCS 00 and PDDCS 20 , in the center-of-mass frame. The results indicate that the vector properties are sensitive to the reagent vibrational quantum number.     

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 reagent vibration on the stereodynamics of the Li + HF → LiF + H reaction

We investigate the influence of reagent vibration on the stereodynamics of the title reaction by the quasi-classical trajectory on the Aguado-Paniagua2-potential energy surface developed by Aguado et al. (J. Chem. Phys. 1997 106 1013). The cross sections and reaction probability as functions of the reagent vibration are calculated in the centre-of-mass frame. The product angular distributions of p(θ_r), p(φ_r), and p(θ_r, φ_r), which reflect the vector correlation, are also presented and discussed. The results indicate that the vector properties are sensitively affected by the vibrational excitation.     

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.     

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104.5 kJ/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H_{2相似文献}   

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(θ_r)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(φ_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(φ_r)分布和极化微分反应截面也有较大影响. 关键词： 矢量相关 立体动力学 准经典轨线方法 极化微分反应截面     

Vibrational and rotational excitation effects of the N(2D) + D2(X1Σg +) → ND(X3Σ+) + D(2S) reaction

The effects of the rovibrational excitation of reactants in the N(²D) + D₂(X¹Σ_g⁺) → ND(X³Σ⁺) + D(²S) reaction are calculated in a collision energy range from the threshold to 1.0 eV using the time-dependent wave packet approach and a second-order split operator. The reaction probability, integral cross-section, differential cross-section and rate constant of the title reaction are calculated. The integral cross-section and rate constant of the initial states v = 0, j = 0, 1, are in good agreement with experimental data available in the literature. The rotational excitation of the D₂ molecule has little effect on reaction probability, integral cross-section and the rate constant, but it increased the sideways and forward scattering signals. The vibrational excitation of the D₂ molecule reduced the threshold and broke up the forward–backward symmetry of the differential cross-section; it also increased the forward scattering signals. This may be because the vibrational excitation of the D₂ molecule reduced the lifetime of the intermediate complex.     

Stereodynamics of the reaction He+H<Stack><Subscript>2</Subscript><Superscript>+</Superscript></Stack> → HeH<Superscript>+</Superscript> + H: a theoretical study

Quasiclassical trajectory method for the title reaction He +H₂⁺ → HeH⁺ + H was carried out on the potential energy surface which was revised by Aquilanti et al. [Chem. Phys. Lett. 469, 26 (2009)]. The initial vibrational quantum number of reactant was set as v=1, v=2 and v=3. Stereodynamics information of the reaction was obtained, such as the distributions of product angular momentum P(θ _r ), P(ϕ _r ),p(ϕ _r , θ _r ) and the two commonly used polarization-dependent differential cross sections (PDDCSs) (2π/σ)(dσ ₀₀/dω _t ) and (2π/σ)(dσ ₂₀/dω _t ), to get the alignment and orientation of product molecules. The results show that the influence of both the collision energy and vibrational quantum number (v) to the reaction are highly sensitive.     

Semirigid vibrating rotor target calculation for reaction O(<Superscript>3</Superscript>P)+CH<Subscript>4</Subscript>→CH<Subscript>3</Subscript>+OH

The time-dependent quantum dynamics calculation for reaction O(³P)+CH₄ →CH₃+OH is made, using of the semirigid vibrating rotor target (SVRT) model and the time-dependent wave packet (TDWP) method. The corresponding reaction probabilities of different initial states are provided. From the calculation of initial rovibrational statej=0,v=0, 1, we can see that the excitation of the H-CH₃ stretching vibration gives significant enhancement of reaction probability and the reaction threshold decreases dramatically with the enhancement of the vibrating excitation, which indicates that the vibrating energy of reagent molecules contributes a lot to the molecular collision. As for the calculation of reaction probability of statev=0,j=0,1,2,3, the results show that the reaction probability rises significantly with the enhancement of rotational quantum numberj while the reaction threshold has no changes. The spatial steric effect of the title reaction is studied and analyzed too after the calculation of reaction probability of statesj=5,k=0–2,n=0 andj=5,k=2,n=0–2 is made.     

Effects of reagent's rotational and vibrational excitations on reaction O(3P) + H2 H2(ν = 0, 3, j = 0, 3; 5; 7; 9; 12; 15) → OH + H

To investigate the effect of reagent's rotational and vibrational excitations on the stereo-dynamics of reaction product, the title reaction is theoretically simulated using the quasi-classical trajectory (QCT) method on the ³A" and ³A′ potential 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.     

低能电子与氢分子碰撞的振动激发积分散射截面的研究

采用振动密耦合方法，研究了低能电子与H₂分子碰撞的振动激发积分散射截面.研究表明，使用18个Morse振动波函数、5个分波和4个对称性可以得到收敛的0→0，0→1，0→2和0→3积分散射截面；而且振动波函数的性质和振动能级的精确性会直接影响振动激发散射势能和振动激发积分散射截面.计算结果与实验符合得很好. 关键词： 电子散射 振动激发 2分子')" href="#">H₂分子 积分截面