H+H2(v=0,1)→H2(v′)+H反应截面的电子非绝热三维量子散射近似计算

本文把电子非绝热一维量子散射反应几率和三维量子散射反应截面的近似公式结合起来, 对于反应物分子(H_2)不同的量子振动态(v=0, 1) 分别计算了H+H_2(v=0)→H_2(v′=0, 1)+H和H+H_2(v=1)→H_2(v′=0, 1)+H的平均反应截面σ_0和σ_1, 并同文献上用电子绝热理论计算的结果作了比较, 表明对这类中性原予-分子反应碰撞的过程, 特别是当反应物分子处于振动激发态时, 电子非绝热效应是存在的。

AN APPROXIMATE QUANTUM SCATTERING CALCULATION OF 3-DIMENSIONAL REACTION CROSS SECTION FOR H+H2(v)→H2(v')+H EXCHANGE REACTION WITH ELECTRONIC NON-ADIABATIC COUPLING EFFECTS

The exchange reaction between a hydrogen atom and a hydogen molecule provi- des the simplest ease where for neutral species the concerted kinetic processes of bond breaking and bond formation can be studied experimentally and theoreti- cally. The collision dynamics of the H+H_2 system have been studied by quasi-and semielassical as well as by approximate and accurate quantum methods using semi- empirical and fitted ab initio H_3 surfaces. But both approximate approaches and close-coupling technique of the electroniclly adiabatic theory yield results of the rate constant of the exchange reaction H+H_2(v=1) which are over an order of magnitude lower than the measured total rate constant. The evident disagreement between theory and experiment for this reaction, which should be the best-under-stood of all chemical processes, surely provides a continuing theoretically and experimental challenge.A closed-coupling differential equation of the collinear A+BC→AB+C system involving electronically excited effect has been obtained by us early, with which wa have calculated the reaction probabilities of colinear reaction H+H_2 (v=0, 1)→H_2(v′=0, 1)+H on the PK semiemperical H_3 potential energy surface....