丙烯腈双自由基终止过程态密度变化的研究（英文）

State density change of the termination of two acrylonitrile radicals

本文采用密度泛函理论对丙烯腈单体自由基(CH3)2(CN)C-CH2-(CN)CH两种终止反应过程中各原子态密度变化进行研究.用B3LYP/6-31G(d)基组对反应物、偶合中间体、过渡态和产物的结构进行优化,计算了各物种的红外频率和各原子的态密度.研究结果表明,偶合中间体a和歧化产物P的化学稳定性较好,丙烯腈单体自由基R和过渡态TS的化学稳定性比较差;各驻点物种的HOMO、LUMO轨道基本是相同原子贡献,且C、N原子贡献程度基本在95%左右;丙烯腈单体自由基R、过渡态TS的HOMO、LUMO相对比较独立,与前线轨道附近的其他能级(HOMO-2、HOMO-1、LUMO+1、LUMO+2)的能量差比较大.

A theoretical study of density of states （DOS） changes for the reaction of two （ CH3 ） 2 （CN） C - CH2 - （CN）CH is carried out at the density functional theory B3LYP/6 -31G（d） level. The structures and of reactants, coupled intermediates, transition states and products are optimized, and their IR spectra and DOS are calculated. Results show that, the chemical stability of coupled intermediate a and disproportioned product P are great, and these for acrylonitrile monomer radicals R and transition state TS show the opposite; HOMO and LU- MO of stationary points are mostly contributed by carbon atom and nitrogen atom at around 95 % ; the HOMO and LUMO of acrylonitrile radical R and transition state TS are relatively independent, and they are much different from other energy levels （ HOMO - 2, HOMO - 1, LUMO ＋ 1 and LUMO ＋ 2） around the frontier orbital.