摘要
本文使用分子轨道从头算方法，在ＨＦ／６—３１Ｇ和ＭＰ２／６—３１Ｇ“水平下，计算了小硅化物ＳｉＸｍ的平衡几何和谐振子振动频率。理论值和实验值的比较表明，对于ＳｉＨｍ分子，实验的键长位于ＨＦ键长和ＭＰ２键长之间，而ＭＰ２振动频率更接近于实验的振动；率。对于ＳｉＣｌｍ分子，无论是键长还是振动频率ＨＦ值和ＭＰ２值都比较接近。对于ＳｉＦｍ分子，处于这两类的中间情况。关联作用随着Ｘ原子的原子序数的增加而减弱。
The equilibrium geometries and harmonic vibrational frequencies of small silicon compounds SiXm (X=H,F,Cl; m =1-4 ) are calculated by using Ab initio molecular orbital theory at the HF/6-31G and MP2/6-31G levels. The comparisons between theoretical values and experimental values indicate that experimental bond lengths lie between HF and MP2 bond lengths, and MP2 vibrahonal frequencies are more closed to experimental values than HF vibrational frequencies for SiHm molecules. Both bond lengths or vibrational frequencies, HF values are claied to MP2 values for SiClm molecules. For SiFm molecules, the cases are between SiHm and SiClm. The effects of electron correlation are decreased with increaSing atomic number of atom X.
出处
《原子与分子物理学报》
CSCD
北大核心
1994年第2期193-198,共6页
Journal of Atomic and Molecular Physics
基金
国家自然科学基金
关键词
硅化物
平衡
振动频率
从头计算法
silicon compounds
Ab initio molecular orbital
Equilibrium geometries
Harmonic vibrational frequencies
Effects of electron correlation
