烷基硫自由基的结构、电子亲合能和热化学性质的研究

A STUDY ON STRUCTURES,ELECTRON AFFINITIES AND THERMOCHEMICAL PROPERTIES OF MERCAPTYL RADICALS

采用G3和四种密度泛函(DFT)方法对几种烷基硫自由基的分子构型进行了优化,得到这些物质基态构型下一系列典型的性质,如:键长、键角、总能量、电子亲合能、电离能、键的解离能及振动频率等,分析了所有分子的红外吸收光谱,结果表明G3、B3LYP、BP86方法预测的电子亲合能与实验值吻合得非常好。同时,G3方法预测的电离能与已知实验值也有较好的吻合。

Molecular structures of mercaptyl radicals have been determined witll the help of G3 theory and four DFT （density functional theory ）schemes. Some molecular properties including optimal geometries, bond lengths, bond angles, total energies, electron affinities, ionization energies （IE）, bond dissociation energies （DE） and vibration frequencies of these species have been calculated. Geometric parameters predicted by the MP2 （full）/6 - 31 G （d） method are presented and the simulated IR spectra of all molecules are analyzed. Consequently ,the G3, B3LYP and BP86 methods are found to be able to yield the most reliable electron affinities for these molecular systems. The IE values predicted by the G3 theory also well conform to available experimental results.