去氢抗坏血酸分子振动光谱的理论研究

Theoretical Investigation on the Vibrational Spectra of Dehydroascorbic Acid

采用RHF,MP2,DFT(B3LYP)方法,以6-311++G**为基组研究了去氢抗坏血酸分子(DHA)的平衡几何构型和振动光谱.计算结果表明,采用RHF,B3LYP以及MP2方法优化得到的几何结构以及频率值是一致的.采用B3LYP/6-311++G**计算了DHA分子平衡构型下的谐振动力场、振动频率和振动强度.使用Wilson的GF矩阵方法对DHA分子进行了简正坐标分析,依据所得的势能分布对DHA分子的振动基频进行了合理的理论归属.

In the present study, restricted Hartree-Fock （ RHF）, Moller-Plesset order 2 （MP2） and density functional theory（DFF） methods with 6-311 ＋ ＋ G^＊ ＊ basis set were performed to study equilibrium geometry and vibrational spectra of dehydroascorbic acid. The calculated results show that RHF, MP2 and B3LYP methods have accordance on equilibrium geometry and frequencies. On the basis of the optimized structure, the harmonic fields, vibrational frequencies and infrared intensities were calculated at B3 LYP/6-311 ＋ ＋ G^ ＊ ＊ level. A normal coordinate analysis was carried out using GF matrix method developed by Wilson. The assign- ment of fundamental vibrations for DHA molecule was obtained according to the potential energy distributions （PEDs）.