ClC(O)NCS分子振动光谱的理论研究

采用密度泛函理论DFT(B3LYP)方法,以6-31G^*为基组对ClC(O)NCS的反式和顺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^*的理论力场由适用于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ClC(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 ClC(O)NCS

The optimized geometries, vibrational force fields and infrared intensities of trans and cis forms of ClC(O)NCS were calculated by density functional theory (DFT) method with 6 31G * basis set. The theoretical force fields of B3LYP/6 31G * were scaled by using the scaled quantum mechanical (SQM) force field method. The scale factors were taken from the previous results of Pulay. The average deviations between the experimental and computed frequencies are 7.3 and 8.1 cm -1 for the trans and cis isomers of ClC(O)NCS, respectively. The assignments of the fundamentals for the two rotational conformers of this molecule were also performed according to the potential energy distribution (PED) and the infrared intensities.