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用密度泛函方法ＢＬＹＰ、Ｂ３ＬＹＰ和从头算 Ｈａｒｔｒｅｅ－Ｆｏｃｋ （ＨＦ）方法在 ６－３１Ｇ基组水平 上对丙酮酸分子的几何结构（甲基的重叠式和交错式两种构象）和振动光谱分别进行了优化和计 算，并给出了各种频率所对应的红外强度及拉曼活性，对光谱进行了指认。结果表明：在丙酮酸分子 的两种构象中，重叠式比较稳定。Ｂ３ＬＹＰ计算得到的构型参数与实验结果比较一致；在振动频率的 计算中，ＢＬＹＰ标度力场所计算的非ＣＨ３伸缩振动基频预测值和实验值的平均绝对偏差为 １０．４ｃｍ－１；而ＨＦ标度力场的平均绝对偏差为１７．９ｃｍ－１。说明两者的结果与实验观测频率比较吻 合，但Ｂ３ＬＹＰ的频率计算值偏差（３８．３ ｃｍ－１）较大。根据振动频率的势能分布和红外光谱强度对此 分子的振动基频进行了理论归属。
The geometric structures of pyruvate (both overlapping and interlaced methyl groups) and vibrational spectra of pyruvate at the 6-31G basis set were studied using the density functional method BLYP, B3LYP and ab initio Hartree-Fock (HF) The optimization and calculation were carried out. The infrared intensity and Raman activity of various frequencies were given, and the spectrum was identified. The results show that in the two conformations of pyruvate molecules, the overlap is relatively stable. The calculated configuration parameters of B3LYP are in good agreement with the experimental results. In the calculation of vibration frequency, the average absolute deviation of predicted and experimental values of non-CH3 stretching vibration calculated by BLYP scale force field is 10.4cm-1; The average absolute deviation of the HF scale force field is 17.9 cm -1. The result shows that the frequency of B3LYP is larger than that of the experimental observation frequency (38.3 cm-1). According to the distribution of potential energy of vibrational frequency and the intensity of infrared spectrum, the fundamental frequency of vibration of the molecule is theoretically assigned.