摘要
用从头算分子轨道法，在UHF／6－31G**水平上研究了CH3O与NO在单、三态势能面上的反应机理，发现该反应在两个势能面上均存在两个彼此平行的反应途径，分别生成产物CH3ONO（a）和HCHO＋HNO（b）．优化了四个途径的所有驻点的几何构型，用Morokuma的数值分析方法计算了它们的内禀反应坐标（IRC），各途径经零点能（ZPE）校正的活化位垒，单重态途径（a）为86．86kJ·mol-1，途径（b）为159．22kJ·mol-1；三重态途径（a）为139．20kJ·mol-1，途径（b）为196．49kJ·mol-1．表明在单重态势能面发生反应更为有利，且该反应更容易生成CH3ONO产物．此结论与实验结果一致．
Ab initio UHF/6-31G** method have been used to study the reaction mechanism of CH3O with NO on the singlet and triplet potential energy surfaces. Two parallel reaction channels, leading to products CH3ONO(a) and HCHO+HNO(b), were separately found on these potential energy surfaces. The Intrinsic Reaction Coordinates (IRC) for the above reactions were traced by using the algorithm of Morokuma. The activation barriers at 6-31G**+ZPE level are 86-86 kJ.mol-1 and 159.22 kJ.mol-1 respectively for path(a) and path(b) on the singlet-state surface, and 139.20 kJ.mol-1 and 196.49 kJ.mol-1 repectively on the triplet-state suxface. The theoretical results show that the reaction occurs more favorably on the singlet-state surface and that CH3ONO is predominately produced than other products, which is in agreement with the experimental result.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
1996年第5期391-395,共5页
Acta Physico-Chimica Sinica
基金
国家科委基金
