Non-adiabatic quantum dynamical studies of Na(3p) + HD(v = 1, j5) = 0)→NaH/NaD + D/H reaction

Non-adiabatic dynamical calculations are carried out for the Na(3 p)+HD(ν = 1, j = 0)→NaH/NaD+D/H reaction on the diabatic potential energy surfaces of Wang et al.(Sci. Rep. 2018, 8, 17960) by using the time-dependent wave packet method. The state-to-state integral cross sections and differential cross sections of two reaction channels(NaH/NaD+D/H)are calculated for collision energy up to 0.4 eV. The cross section branching ratio indicates that the dominant reaction channel changes from NaD+H to NaH+D when the collision energy is larger than 0.227 eV. The products from two reaction channels both prefer to form in vibrationally cold but rotationally hot states, and they both tend to forward scattering.     

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.     

Theoretical Studies of O(1D)+HD (v=0, j=0, 1, 2, 3)→OD(H)+H(D) Reaction

利用准经典轨线计算方法在DK势能面上对O+HD进行了计算,获得了产物的反应截面和分支比OD/OH. 计算结果表明,当碰撞能由4.6 kJ/mol增加到46.0 kJ/mol时,产物的反应截面随着碰撞能的增加明显减小;产物的平均分支比随着转动量子数的增加逐渐减小.     

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.     

Effects of collision energy and rotational quantum number on stereodynamics of the reactions:H(~2S)+NH(v=0,j=0,2,5,10)→N(~4S)+H_2

The stereodynamical properties of H(~2S) + NH(v = 0,j = 0,2,5,10)→N(~4S) + H_2 reactions are studied in this paper by using the quasi-classical trajectory(QCT) method with different collision energies on the double many-body expansion(DMBE) potential energy surface(PES)(Poveda L A and Varandas A J C 2005 Phys.Chem.Chem.Phys.7 2867).In a range of collision energy from 2 to 20 kcal/mol,the vibrational rotational quantum numbers of the NH molecules are specifically investigated on v = 0 and j = 0,2,5,10 respectively.The distributions of P(θ_r),P(φ_r),P(θ_r,φ_r),(2π/σ)(dσ_(00)/dω_t)differential cross-section(DCSs) and integral cross-sections(ICSs) are calculated.The ICSs,computed for collision energies from 2 kcal/mol to 20 kcal/mol,for the ground state are in good agreement with the cited data.The results show that the reagent rotational quantum number and initial collision energy both have a significant effect on the distributions of the k-j',the k-k'-j',and the k-k' correlations.In addition,the DCS is found to be susceptible to collision energy,but it is not significantly affected by the rotational excitation of reagent.     

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.     

Dynamics studies of O+ + D2 reaction using the time-dependent wave packet method

Based on the potential energy surface (PES) reported by Li et al. (Phys. Chem. Chem. Phys. 20, 1039 (2018)), the initial state dynamics calculation of O⁺?+?D₂ (v?=?0, j?=?0) reaction was conducted using the time-dependent wave packet method with a second order split operator. Dynamics properties such as reaction probability, integral cross section, differential cross section, and distribution of products were calculated and compared with available experimental and theoretical results. The present integral cross section values were in good agreement with experimental results. In addition, the differential cross section indicates that the mechanism of the complex-formation reaction plays a dominant role during the reaction.     

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.     

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) $({2\pi } / \sigma )(\d\sigma _{00} / \d\omega _t )$, $({2\pi } / \sigma )(\d\sigma _{20} / \d\omega _t )$, $({2\pi } / \sigma )(\d\sigma _{22 + } / \d\omega _t )$, and $({2\pi } / \sigma )(\d\sigma _{21 - } / \d\omega _t )$ are calculated in the centre-of-mass frame. The distribution of the angle between ${{\bm k}}$ and ${{\bm j^\prime }}$, $P(\theta _r )$, the distribution of the dihedral angle denoting ${{\bm k}}${--}$\bm k^\prime $--$\bm j^\prime $ correlation, $P(\phi _r )$, as well as the angular distribution of product rotational vectors in the form of polar plots $P(\theta _r ,\phi _r )$ are calculated. The isotope effect is also revealed and primarily attributed to the difference in mass factor between the two title reactions.     

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(X3∑-) →N(4S)+H2 on the ground state 4A' potential energy surface(PES) constructed by Zhai and Han [2011 J.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-k' 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(θr) is strongly dependent on the collision energy below the lower collision energy(about 11.53 kcal/mol).In addition,the P(φr) 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.     

Isotopic effects of the N(2D) + H2 → NH + H reaction: a quantum time-dependent wave packet investigation

Based on the potential energy surface reported by Li and co-workers (J. Comput. Chem. 34 1686–1696 (2013)), the dynamics calculations of N(²D)?+?H₂(v ₀?=?0, j ₀?=?0) reaction and its isotopic variants HD and D₂ are studied using time-dependent wave packet method in the collision energy range of 0.01–1.0?eV. Dynamics properties such as reaction probability, differential cross section, and integral cross section are studied at state-to-state level of theory. Present values are compared with available theoretical and experimental results. The results indicate that the integral cross sections of N(²D)?+?D₂ reaction are in general good agreement with the experimental data at collision energy below 0.15?eV. The rotational state-resolved integral cross sections of N(²D)?+?H₂/HD/D₂ reactions are compared with experimental values for the first time, with the obtained values being in good agreement with the experimental data.     

Quasi-classical trajectory study of H+LiH(v=0,1,2,j=0)→Li+H_2 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+H_2 reaction on a new ground electronic state global potential energy surface(PES) of the LiH_2 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.     

Theoretical study of stereodynamics for the D'+DS(ν = 0,j = 0)→D'D+S abstraction reaction

Quasiclassical trajectory (QCT) calculations have been performed for the abstraction reaction, D' +DS(v = 0, j = 0)→D'D+S on a new LZHH potential energy surface (PES) of the adiabatic 3A' electronic state [Lü et al. 2012 J. Chem. Phys. 136 094308]. The collision energy effect on the integral cross section and product polarization are studied over a wide collision energy range from 0.1 to 2.0 eV. The cross sections calculated by the QCT procedure are in good accordance with previous quantum wave packet results. The three angular distribution functions, P(θ_r), P(φ_r), and P(θ_r,φ_r), together with the four commonly used polarization-dependent differential cross sections ((2π/σ)(ds₀₀/dω_t), (2π/σ)(ds₂₀/dω_t), (2π/σ)(ds₂₂₊/dω_t), (2π/σ)(ds_21-/dω_t)) are obtained to gain insight into the chemical stereodynamics of the title reaction. Influences of the collision energy on the product polarization are exhibited and discussed.     

Quasi-classical trajectory study of the isotope effect on the stereodynamics in the reaction H(2S)+CH(X2Π; v=0, j=1)→C(1D)+H2(X1Σg+)

The isotope effect on the stereodynamic properties in the title reaction is investigated by a quasi-classical trajectory (QCT) method on the 1¹A' potential energy surface at a collision energy of 23.06 kcal/mol. The angular distributions P(θ_r), P(ø_r), P(θ_r, ø_r), 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.     

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.     

The stereodynamic properties of the F + HO (v,j)→HF + O reaction on the 1A' and 3A' potential energy surfaces by quasi-classical trajectory: 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 ¹A' and ³A' 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 vibrational-rotational 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 ³A' 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 ³A' potential energy surface than for the ¹A' potential energy surface.