CH2(3B1)与NO反应的势能面和速率常数的理论计算

CH2(3B1)与NO的自由基碰撞反应已有许多实验研究,得到了其反应的主要通道[1-3].从理论角度来探讨其反应的途径,目前报导较少.虽然实验对其反应的总反应速率常数有较多的报导[1,5-6],但是从理论上来研究其碰撞过程和计算速率常数的工作尚未有报道.本文用多参考态组态相互作用(MRCI)方法,其中参考态是采用完全活化空间(CAS),所选的活化空间是3个活化电子和3个活化轨道,组态相互作用考虑了除C,N和O的1s轨道以外的所有轨道的单激发和双激发组态,所用基组是cc-pvDZ标准基组,这种方法通常写作CAS(3,3)+1+2/cc-pvDZ.在此模型下计算出反应速率常数k,并与实验数据进行了比较.

THEORETICAL CALCULATION ON POTENTIAL SURFACE AND RATE CONSTANT FOR THE REACTION BETWEEN CH2(3B1) AND NO

The geometries of the reactants and product for the titled reaction are optimized at CAS(3,3)+1+2/cc-pvDZ level. The energetics of some crucial points along the minimum energy path are refined by CAS(3,3)+1+2/cc-pvTZ method. Based on RRKM theory, the rate constants for the titled reaction are calculated with the geometries and frequencies of CAS(3,3)+1+2/cc-pvDZ. The obtained values are in good agreement with the experimental ones.