论文部分内容阅读
用量子化学从头计算法对氧原子与羟亚甲基自由基在最低双重态势能面上的反应进行了研究,计算了势能面上各驻点的构型参数、振动频率和能量。计算采用G2(MP2)理论方法。计算结果表明,反应首先形成中间体OCH_2OH,而后经不同过渡态解离为H_2CO+OH或H+HCOOH。由中间体形成甲醛和甲酸的过渡态的能量分别比反应物低202.5和355.3kJ/mol,计算得到2个反应通道的反应热分别为-314.1和-402.9kJ/mol,与实验结果(-307和-398kJ/mol)符合很好。根据能量数据可以预言形成甲酸的通道将是主要的反应通道。
Quantum chemistry ab initio method was used to study the reaction of oxygen atom and hydroxyl methylene radical on the lowest doublet potential energy surface. The configuration parameters, vibration frequency and energy of each stationary point on the potential energy surface were calculated. Calculated using G2 (MP2) theory. The calculation results show that the reaction first forms the intermediate OCH 2 OH and then dissociates to H 2 CO + OH or H + HCOOH via different transition states. The energy of transition state between formaldehyde and formic acid formed by the intermediates was 202.5 and 355.3 kJ / mol lower than that of the reactants respectively. The calculated reaction heats of the two reaction channels were -314.1 and -402.9 kJ / mol, respectively. The experimental results (-307 And -398 kJ / mol) in good agreement. It can be predicted from the energy data that the formic acid-forming channel will be the main reaction channel.