FC(O)NCS 分子振动光谱的理论研究

采用DFT(B3LYP)方法，以6-3G*为基组对FC(O)NCS的顺式和反式两种构型的几何结构，振动谐性力场和红外光谱进行了研究。B3LYP/6-31G*计算水平和大多数有机分子的一套固定标度因子进行标度。根据标度后的理论力场进行简正坐标分析得到的势能分布(PED)和红外光谱强度值对FC(O)NCS分子的顺式和反式两种构型的振动基频进行了理论归属。

Theoretical studies on vibrational spectra of FC(O)NCS

The optimized geometries, vibrational force fields and infrared intensities of FC (O) NCS were calculated by HF, MP2, DFT(B3LYP) methods with 6 - 31G* basis set. The theoretical force field of B3LYP/6 - 31G* were scaled using the scaled quantum mechanical force field method of Pulay. The average deviations between the experimental and computed frequencies are 10 and 13 cm-1 for the cis - and trans -isomers of FC(O)NCS, respectively. The assignments of the fundamentals for two rotational conformers of this molecule were also performed according to the potential energy distribution and the infrared intensities.