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.     

碰撞能对S(1D) +H2(v=0, j=0)→SH+H反应立体动力学性质的影响

利用1A′态的势能面[ Ho et al., J. Chem. Phys. 116, 4124 (2002)],采用准经典轨线方法研究了在不同碰撞能条件下,S(1D) +H2(v=0, j=0)→SH+H反应的立体动力学性质. 通过计算得到了描述反应物速度矢量k与产物的转动角动量矢量j′这两个矢量相关的分布函数P(r)、描述反应物速度矢量k、产物速度矢量k′与产物的转动角动量矢量j′这三个矢量相关的二面角分布函数P(r)以及描述反应产物角动量极化的分布函数P(r,r).计算结果表明产物的转动角动量矢量j′在空间具有明显的定向和取向效应,并且产物的转动角动量具有强烈的极化. 另外,计算结果还表明这些立体动力学性质对碰撞能非常敏感.     

碰撞能对S(1D) +H2(v=0, j=0)→SH+H反应立体动力学性质的影响

利用1A′态的势能面[ Ho et al., J. Chem. Phys. 116, 4124 (2002)],采用准经典轨线方法研究了在不同碰撞能条件下,S(1D) +H2(v=0, j=0)→SH+H反应的立体动力学性质. 通过计算得到了描述反应物速度矢量k与产物的转动角动量矢量j′这两个矢量相关的分布函数P(r)、描述反应物速度矢量k、产物速度矢量k′与产物的转动角动量矢量j′这三个矢量相关的二面角分布函数P(r)以及描述反应产物角动量极化的分布函数P(r,r).计算结果表明产物的转动角动量矢量j′在空间具有明显的定向和取向效应,并且产物的转动角动量具有强烈的极化. 另外,计算结果还表明这些立体动力学性质对碰撞能非常敏感.     

碰撞能对O++DH (v=0, j=0)→OD++H的准经典轨线

运用准经典轨线的方法,基于RODRIGO势能面,研究反应体系O⁺+DH (v=0, j=0)→OD⁺+H的立体动力学性质. 对描述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(φr)以及产物转动取向参数进行了详细的讨论,发现极化微分反应截面呈现有趣的现象. 计算了反应几率与反应截面. O⁺+DH (v=0, j=0)→OD⁺+H反应的立体动力学性质对体系的碰撞能非常敏感.     

Product polarization and mechanism of Li + HF(v=0, j=0) → LiF(v', j') + H collision reaction

A state-to-state dynamics analysis for the Li+HF(v=0,j=0)→LiF(v',j')+H collision reaction has been performed through quasiclassical trajectory(QCT)calculations.It is found that the differential cross section(DCS)of the LiF products from the title reaction is preferentially backward scattering for v=0,yet forward scattering for v=1 and 2.For v=3,the DCS exhibits forward,backward,and sideways scatterings.The variation of the internuclear distances and angles along the propagation time reveals that more than 99.08%of reaction trajectories undergo the direct reaction mechanism.The values of the polarization parameters a{1}1and a{2}0demonstrate that the product rotational angular moment j' is not only aligned perpendicular to the reagent relative velocity vector,but also oriented along the negative y axis.These product polarization results agree well with the recent quantum mechanical studies.The mechanism of these results was proposed and discussed in detail.     

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     

Na2(A1∑u+,v=8～b3Ⅱ0u,v=14)-Na体系转动传能的碰撞量子干涉效应

沙国河及其工作组于1995年发表了CO A1Π(v=0)～e3∑-(v=1)与He1,Ne及其它碰撞伴的碰撞过程中转动传能的碰撞量子干涉现象,并得到了积分干涉角,陈等从理论和实验上发现了Na2(A1∑u ,v=8～b3Π0u,v=14)体系与Na(3s)碰撞的碰撞量子干涉现象,孙等计算了其积分干涉角,但是对微分干涉角没有过多的计算.本文作为对原子-双原子体系碰撞诱导转动传能的进一步理论研究,在含时一级波恩近似的基础上考虑各向异性相互作用势和长程相互作用势,计算了单叁混合态的Na2(A1∑u ,v=8-bΠ0u,v=14)体系与Na碰撞的微分干涉角,并得到了微分干涉角与碰撞参数的关系,此理论模型对理解和进行分子束实验是非常重要的.     

C+OH(v=0—3,j=0—3)→CO+H反应的准经典轨线研究

运用准经典轨线方法,在碰撞能为1.0eV时,研究了反应物OH分子的振转激发对C+OH反应的立体动力学性质的影响.详细地讨论了该反应在不同反应物振转态下的矢量性质.计算表明,OH分子的振转激发对C+OH反应的矢量性质非常敏感,这种现象在对该反应的标量性质的研究中是不存在的.     

C+OH(v=0-3,j=0-6)→CO+H反应的准经典轨线研究

运用准经典轨线方法,在碰撞能为1.0eV时,研究了反应物OH分子的振转激发对C+OH反应的立体动力学性质的影响.详细地讨论了该反应在不同反应物振转态下的矢量性质.计算表明,OH分子的振转激发对C+OH反应的矢量性质非常敏感,这种现象在对该反应的标量性质的研究中是不存在的.     

Na_2(A~1∑_u~+,v=8～b~3∏_(0u),v=14)-Na体系转动传能的碰撞量子干涉效应(英文)

沙国河及其工作组于1995年发表了COA^1∏（v=0）～e^3∑^-（v=1）与He,Ne及其它碰撞伴的碰撞过程中转动传能的碰撞量子干涉现象,并得到了积分干涉角,陈等从理论和实验上发现了Na2（A^1∑u^＋,v=8～b^3∏0u,v=14）体系与Na（3s）碰撞的碰撞量子干涉现象,孙等计算了其积分干涉角,但是对微分干涉角没有过多的计算.本文作为对原子-双原子体系碰撞诱导转动传能的进一步理论研究,在含时一级波恩近似的基础上考虑各向异性相互作用势和长程相互作用势,计算了单叁混合态的Na2（A^1∑u^＋,v=8～b^3∏0u,v=14）体系与Na碰撞的微分干涉角,并得到了微分干涉角与碰撞参数的关系,此理论模型对理解和进行分子束实验是非常重要的.     

State-to-state quantum dynamics of N(~2D)+HD(v=0,j=0) reaction

The N(~2D) + HD(v = 0, j = 0) reaction has been studied by a quantum time-dependent wave packet approach with a second-order split operator on the potential energy surface of Li et al.(Li Y, Yuan J, Chen M, Ma F and Sun M J. Comput.Chem. 34 1686). The rovibrationally resolved reaction probability, vibrationally integral cross section, and differential cross section of the NH + D and ND + H channel are investigated at the state-to-state level of theory. The experimental data of the thermal rate constant of two output channels is very scare, but the sum of the two output channels is in excellent agreement with the experimental data which was reported by Umemoto et al. It may imply that the thermal rate constants of the two output channels are accurate and reliable.     

Theoretical study of the dynamics for the H + Li H ( v = 0, j = 0) $\to$ H2 + Li reaction and its isotopic variants

Quasi-classical trajectory (QCT) method is carried out to calculate the dynamics of the H + LiH (v = 0, j = 0) ?\to H₂ + Li reaction and its isotopic variants based on the potential energy surface of the lowest ²A￠^2A' electronic state reported by Prudente et al. [Chem. Phys. Lett. 474, 18 (2009)]. The reaction cross-section, product rotational alignment parameter áP₂\langle P_2 ([(j￠)\vec]\vec{j'} ·\cdot [(k)\vec])?\vec{k})\rangle and one generalized polarization-dependent differential cross-section (2π/σ)(ds₀₀d\sigma_{00}/d w_t\omega_t) are calculated. We found that different collision energies and mass factors show driving influence on the process of the reactions and product molecules H₂ (HD, D₂) polarization distribution, and the trend of the isotopic effects in the high collision energy range is different to that in the low collision energy range. The calculations are also interpreted in relation to the features of the underlying potential energy surface. A comparison between the title reactions and a barrier-less reaction F + HBr ?\to FH + Br has been discussed in detail.     

Observation of predicted resonance structure in the H+D2 --> HD(v(') = 0, j(') = 7) + D reaction at a collision energy of 0.94 eV

We present experimental verification of predicted resonance structure in the energy dependence of the H+D2 reaction. Specifically we predict and observe a broad resonance in the H+D2-->HD(v(') = 0,j(') = 7)+D reaction at a collision energy of 0. 94 eV. This resonance structure is roughly Gaussian with a full width at half maximum of 0.1 eV. These results represent the first experimentally observed resonance structure in the fundamental H+H2 reaction system.     

0.5 eV时H++D2(v=0,j=0) 反应的微分、积分截面

基于ab initio势能面(KBNN PES)[1],用耦合通道超球坐标理论研究了碰撞能等于0.5 eV时H D2(v=0,j=0)的积分,微分截面.对于反应性碰撞,计算的积分截面表明由于深势阱的存在使得这一绝热反应产物的分布表现出一种近似的统计行为.计算的微分截面反映该体系存在着长寿命的中间络合物;对于非反应性碰撞(传能过程),平动—平动传能过程更有效,且其积分截面随着转动量子数的增大而显著减少.通过反应性碰撞和非反应性碰撞积分截面的比较,发现在低能碰撞情况,非反应性碰撞更容易进行.     

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.     

Theoretical study on collision dynamics of H+ + H2O at low energies

Scattering dynamics of a water molecule in collision with proton is studied based on a time-dependent density functional theory and coupled with the molecular dynamics method, in which the electrons are described by quantum mechanics and the nuclei are described by classical mechanics. Four different incident directions at 46 eV are chosen in order to investigate the orientations effect, and the energy-dependent effect in low energy region is explored under impact energies 27, 36 and 46 eV. Reaction channels, scattering angles and energy loss of protons are calculated. The differences between those characteristics are unobvious in large impact parameters, which are irrespective of the incident orientations due to weak projectile-target interaction. In small impact parameters, the results strongly depend on the collision energy and orientation.     

Analysis of the (0 0 v(3)), v(3) = 1, 2, 3 Vibrotational States of HDSe

High-resolution Fourier transform spectra of HDSe in the region of the 2nu(3) and 3nu(3) bands were recorded and analyzed for five different (M)Se isotopic HDSe species. Energies obtained from rovibrational analyses of the (002) and (003) states, together with those taken of the (001) state from an earlier study [O. N. Ulenov, G. A. Onopenko, N. E. Tyabaeva, H. Bürger, and W. Jerzembeck, J. Mol. Spectrosc. 198, 27-39 (1999)], were used as input information for a "Global Fit" procedure. This fit provided 34 spectroscopic parameters for the HD(80)Se species which reproduced rotational-vibrational transitions of the (001), (002), and (003) states within experimental accuracy. Corresponding analyses were performed for the other (M)Se (M = 82, 78, 77, and 76) species. Copyright 2000 Academic Press.     

The characteristics of O＋HD （v = 0, j = 0） reaction dynamics

The analytical potential energy function of HDO is constructed at first using the many-body expansion method.The reaction dynamics of O+HD(v = 0,j = 0) in five product channels are all studied by quasi-classical trajectory(QCT) method.The results show that the long-lived complex compound HDO is the dominant product at low collision energy.With increasing collision energy,O+HD → OH+D and O+HD → OD+H exchange reactions will occur with remarkable characteristics,such as near threshold energies,different reaction probabilities,and different reaction cross sections,implying the isotopic effect between H and D.With further increasing collision energy(e.g.,up to 502.08 kJ/mol),O+HD → O+H+D will occur and induce the complete dissociation into single O,H,and D atoms.