The reaction mechanism of La-catalyzed C2H4 dehydrogenation was studied on doublet and quartet potential energy surface in the gas phase by density functional theory B3LYP method.The geometries of all species were fully optimized.The transition states of the reaction were confirmed by the vibration frequency calculation and the intrinsic reaction coordinate (IRC) analysis.The bonding properties of the species involved in the reaction were discussed by AIM (atoms in molecules) theory and NBO (natural bond oribtal) analysis methods.2IM1 and 2IM3 were analyzed by density of states (DOS).The results showed that there are two possible paths for the reaction of La and C2H4.The reactions are carried out on the double potential surface and both are exothernic.The bonding analysis indicated that the interaction is a covalent character between the La and C2H4.%采用密度泛函理论中的B3LYP方法研究了气相中过渡金属La在二、四重态势能面上催化C2H4的反应机理.全参数优化了二、四重态势能面上各个驻点的几何构型,同时对过渡态进行了频率分析,使用内禀反应坐标(IRC)方法验证了过渡态的准确性,通过AIM理论和NBO分析方法对主要的驻点进行了键分析,并对2IM1、2IM3进行了态密度分析.结果表明,La与C2H4的反应存在两种可能的路径,反应在二重态势能面上进行且均为放热反应.键分析表明初始复合物中La与C2H4分子之间为共价作用.
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