摘要
采用量子化学中的密度泛函理论B3LYP方法,在AUG cc PVQZ水平上全优化得到了FSSH线型和SSFH 分叉型2种异构体的平衡结构.对可能发生的分子内原子迁移过程的过渡态进行了考察,并进行了振动分析和内 禀反应坐标(IRC)的计算,证实了过渡态的正确性.计算结果表明,线型的FSSH为稳定构型.同时,采用统计热 力学及过渡态理论,研究了2种平衡结构之间相互转化的热力学和动力学性质.根据计算结果,无论是F迁移还是 H迁移,分子内的原子迁移都需要较高的活化能,并且迁移速度较慢.
B3LYP calculations of density functional theory(DFT)with AUG-cc-PVQZ basis set level are used to investigate the equilibrium structures and intramolecular rearrangement reactions of the linear FSSH and branched S=SFH isomers. The calculated results shows that the linear structure is more stable than the branched structure ( lower 63.4 kJ·mol^(-1) corrected with zero point vibrational energy ) energetically. The calculated energy barriers for the intramolecular fluorine atom transfer and hydrogen atom transfer isomerization processes are 222.6 kJ·mol^(-1) and 168.9 kJ·mol^(-1), respectively. The kinetic results demonstrate that the isomerization is a unimolecular one, and the reaction rate is rather slow. It is consistent with thermodynomical results. So the isomerization process should be proceed via the other likely processes.
出处
《西南师范大学学报（自然科学版）》
CAS
CSCD
北大核心
2004年第6期1000-1004,共5页
Journal of Southwest China Normal University(Natural Science Edition)
基金
国家自然科学基金资助项目(20273013)
中国科学院大气物理研究所LAPC开放课题资助项目.
