从头算法对甲基磺酸拉曼光谱振动频率指认

对液态的甲基磺酸进行了拉曼光谱测定。采取从头算法用各种不同的基组 (最大的基组为MP2 / 6 -311+G( 2d ,2 p) )对甲基磺酸的结构和光谱进行了计算 ,得到了甲基磺酸的结构参数及稳定构象信息。采用一个具有Ci 对称的二聚体模型解释了甲基磺酸的液态光谱。对单体和二聚体的甲基磺酸进行了简正坐标计算 ,结果表明二聚体结构是液态甲基磺酸聚积态分子的合理模型。

Ab Initio Calculation and Raman Spectrum Vibrational Assignment of Methane-Sulfonic Acid

The Fourier transform Raman spectrum of liquid methane-sulfonic acid, CH 3SO 2OH, was recorded and the spectral data were interpreted in detail. Ab initio calculations were carried out with different basis sets up to MP2l6-311 G(2d,2p), from which structural parameters and conformational stabilities were determined. The spectrum of the liquid is interpreted on the basis of a dimer structure with C i symmetry. Normal coordinate calculations were carried out for both the monomer and dimer.The results indicate that the differences in wavenumbers for the normal vibrations for the monomer and dimer are relatively small. These calculations also indicate that the dimer structure is a reasonable model for the associated molecules of methane- sulfonic acid in the liquid phase.