丙烯腈双自由基终止过程态密度变化的研究

摘要

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 B 3LYP/6-31G(d) level.The structures and of react-ants , coupled intermediates , transition states and products are optimized , and their IR spectra and DOS are cal-culated .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.