硫氧分子阴离子的QCISD方法研究

QCISD Study of Sulfur Dioxide and Sulfur Trioxide Anions

使用二次组态相互作用(QCISD)方法和 6 3 11G(d),6 3 11+G(d),6 3 11G(2d)及 6 3 11+G(2d)基组研究了SO-2 和SO-3的分子结构,超精细偶合常数(hfcc)及其对应的分子的绝热电子亲合势(AEA).发现在QCISD/6 3 11+G(2d)水平上计算的两个分子离子的结构,hfcc值(在33S和17O上的)和AEA值与实验值符合得都很好(除SO3-中的在33S上的hfcc值比实验值小 2 3 % ).作为比较,我们使用相同基组作了B3LYP方法计算。

The molecular geometries, the proton isotropic hyperfine coupling constants (hfcc) of SO -_2 and SO -_3, and the adiabatic electron affinities (AEAs) of the corresponding neutral molecules have been studied by performinig the quadratic CI calculations including single and double substitutions (QCISD) with the 6-311G(d), 6-311+G(d), 6-311G(2d) and 6-311+G(2d) basis sets. All the results (including geometries, hfcc's, and AEAs) calculated at the QCISD/6-311+G(2d) level are in good agreement with experiment (except the hfcc value on 33S in SO -_3, which is 23% smaller than the experimental value). For comparison purpose, the DFT B3LYP caculations with the same basis sets were also performed. The calculated hfcc's and AEAs are in poor agreement with those of experiment.