Acta Chimica Sinica ›› 1999, Vol. 57 ›› Issue (7): 680-684.

Original Articles

### Si~2Cl~6分子的内旋转能垒和振动基频的理论研究

1. 四川大学化学系.成都(610064)
• 发布日期:1999-07-15

### Computational studies of the structure and vibrational spectra of hexachlorodisilane

Xu Xuejun;Xue Ying;Xie Daiqian;Yan Guosen

1. Sichuan Univ, Dept Chem.Chengdu(610064)
• Published:1999-07-15

Ab initio restricted Hartree-Fock (RHF) calculations and density functional theory calculations using B3^,exchange and Lee-Yang-Parr^, s correlation functionals (B3LYP) with 6-31G^*^*basis set were carried out to study and optimize equilibrium structure and to obtain energies of two rotational conformers and funamental vibrational frequencies in the equilibrium structure for Si~2Cl~6. The optimized structural parameters are in good agreement with experimental results. The calculated potential barriers to internal rotation are 8.786 and 6.694kJ/mol determined from the calculations using HF/6-31G^*^* and B3LYP/6--31G^*^* methods, respectively. The B3LYP/6--31G^*^* value is in good agreement with the observed value of 4.1868kJ/mol. Infrared intensities, Ruaman activities and vibrational frequencies are reported for Si~2Cl~6 under D~3~d symmetry. A normal coordinate analysis employing scaled ab initio (HF/6--31G^*^*) force field has been carried out.The average error between the predicted fundamentals utilizing scaled HF/6--31G^*^* force field with a scale factor of 0.9 pertinent to all vibrational modes and observed fundamental vibrational frequencies is 7.3cm^-^1. Moreover,a mean absolute deviation between fundamentals obtained from B3LYP/6--31G^*^* calculations using unrefined SQM force field and the observed frequencies is 6.0cm^-^1.

CLC Number: