H+LiH及其同位素替代D+LiD反应的动力学研究
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摘要
基于两个LiHH体系基态势能面,采用准经典轨线的方法对H+LiH→H_2+Li及其同位素替代D+LiD→D_2+Li反应进行了动力学研究,计算了基态反应几率、积分反应截面、产物矢量相关性质P(?_r)、极化微分反应截面以及不同振转态对积分反应截面的影响。通过对结果分析比较发现,Yuan-PES势能面具有小势垒,而Li-PES不存在势垒或势阱。基于Yuan-PES的积分反应截面略高于基于Li-PES的积分反应截面,此外还研究了振动激发对产物分子的转动角动量的取向特征和定向特征的影响,以及同位素替代对其的影响;H+LiH反应的前向散射趋势较D+LiD反应更明显,且Yuan-PES的前向散射程度更高。该研究丰富了该体系动力学性质,对以后该体系的实验研究具有一定的参考意义。
Quasi-classical trajectory(QCT) method was used to study on the dynamics theory of the H + LiH → H_2 + Li and its isotopic variant D + LiD → D_2 + Li reaction based on the two ground state potential energy surfaces of LiHH system. The ground state reaction probabilities, integral cross sections, product angular distributions of ■ and polarization dependent differential cross-sections are calculated. We also investigated the effect of vibrational excitation on integral reaction cross section. By comparing and analyzing the results, it was found that the Yuan-PES potential energy surface had a small potential barrier, while the Li-PES did not have a potential barrier or potential well. The integral reaction cross section based on Yuan-PES was slightly higher than that based on Li-PES. In addition, the influence of vibration excitation on the orientation and orientation characteristics of the rotational angular momentum of the product molecules and the influence of isotope substitution on it were also studied. The forward scattering tendency of the +LiH reaction was more pronounced than that of the D+LiD reaction. And the degree of forward scatter of Yuan-PES was higher. It enriched the dynamic properties of the system and had certain reference significance for the experimental research of the system in the future.
Quasi-classical trajectory(QCT) method was used to study on the dynamics theory of the H + LiH → H_2 + Li and its isotopic variant D + LiD → D_2 + Li reaction based on the two ground state potential energy surfaces of LiHH system. The ground state reaction probabilities, integral cross sections, product angular distributions of ■ and polarization dependent differential cross-sections are calculated. We also investigated the effect of vibrational excitation on integral reaction cross section. By comparing and analyzing the results, it was found that the Yuan-PES potential energy surface had a small potential barrier, while the Li-PES did not have a potential barrier or potential well. The integral reaction cross section based on Yuan-PES was slightly higher than that based on Li-PES. In addition, the influence of vibration excitation on the orientation and orientation characteristics of the rotational angular momentum of the product molecules and the influence of isotope substitution on it were also studied. The forward scattering tendency of the +LiH reaction was more pronounced than that of the D+LiD reaction. And the degree of forward scatter of Yuan-PES was higher. It enriched the dynamic properties of the system and had certain reference significance for the experimental research of the system in the future.
引文
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[10]HE X H,ZHANG P Y,DUAN Z X.Isotopic effect on the dynamics of the H/D + LiH/LiD reactions[J]Computational and Theoretical Chemistry,2016,1084:188-195.DOI:10.1016/j.comptc.2016.03.020.
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[2]BODO E,GIANTURCO F A,MARTINAZZO R.The gas-phase lithium chemistry in the early universe:elementary processes,interaction forces and quantum dynamics[J].Physics Reports,2003,384(3):85-119.DOI:10.1016/S0370-1573(03)00243-6.
[3]DUNNE L J,MURRELL J N,JEMMER P.Analytical potential energy surface and quasi-classical dynamics for the reaction LiH(X,1Σ+)+H(2S)→Li(2S)+H2(X,1Σg+) [J].Chem Phys Let,2001,336(1/2):1-6.DOI:10.1016/S0009-2614(01)00102-6.
[4]ROY T,MAHAPATRA S.Quantum dynamics of H + LiH reaction and its isotopic variants [J].J Chem Phys,2012,136(17):174313.DOI:10.1063/1.4707144.
[5]PRUDENTE F V,MARQUES J M C,MANIERO A M.Time-dependent wave packet calculation of the LiH+H reactive scattering on a new potential energy surface [J].Chem Phys Let,2009,474(1/2/3):18-22.DOI:10.1016/j.cplett.2009.04.016.
[6]LIU Y F,HE X H,SHI D H,et al.Theoretical study of the dynamics for the H + LiH (v =0,j =0)→ H2+Li reaction and its isotopic variants.[J]The European Physical Journal D,2011,61(2):349-353.DOI:10.1140/epjd/e2010-10133-0.
[7]SHA G Y,YUAN J C,MENG C G,et al.Influence of early-staged energy barrier on stereodynamics of reaction of LiH (v = 0,j = 0) + H → Li + H2[J].Chem Res Chin Univ,2013,29(5):956-961.10.1007/s40242-013-3134-3.
[8]WERNLI M,CARUSO D,BODO E,et al.Computing a Three-Dimensional Electronic Energy Manifold for the LiH+H→Li+H2 Chemical Reaction [J].J Phys Chem A,2009,113(6):1121-1128.DOI:10.1021/jp809163g.
[9]YUAN J,HE D,CHEN M.A new potential energy surface for the ground electronic state of the LiH2 system,and dynamics studies on the H(2S) + LiH(X1Σ+) → Li(2S) + H2(X1Σg+) reaction[J]Phys Chem Chem Phys,2015,17(17):11732-11739.DOI:10.1039/c4cp05352d.
[10]HE X H,ZHANG P Y,DUAN Z X.Isotopic effect on the dynamics of the H/D + LiH/LiD reactions[J]Computational and Theoretical Chemistry,2016,1084:188-195.DOI:10.1016/j.comptc.2016.03.020.
[11]李琦.H+HLi体系势能面及动力学研究[D].济南:山东师范大学,2016.
[12]郑锡光.原子与分子碰撞反应的准经典轨线运算[D].大连:中科院大连化物所,1991.
[13]张志红.几个典型微观反应体系的准经典轨线计算[D].大连:大连理工大学,2007.DOI:10.7666/d.y1205433.
[14]陶愉生.分子反应动力学[M].北京:科学出版社,1986:5.
[15]韩克利,孙本繁.势能面与分子碰撞理论[M].长春:吉林大学出版社,2009.