外电场作用下CS分子结构及光谱特性研究

Study on the Structural and Spectral Characteristics of CS Molecule under External Electric Fields

为研究分子CS的外场效应,采用密度泛函理论方法在0~0.04a.u.的静电场中对其基态几何结构进行了优化,得到了键长、偶极矩、总能量和电荷分布;在此基础上,采用CIS/B3LYP/6-311G**方法研究了分子紫外-可见吸收光谱随外电场的变化。结果表明:电荷分布随着外电场的增强发生了明显的变化,这种变化使键长不断增加,总能量先增大后减小,偶极矩先减小后增大。紫外-可见吸收峰的波长为246nm,随着外电场的增强,吸收峰发生了显著的蓝移或红移,但波长仍处于紫外范围。

In order to study the influence of external electrical fields on CS molecule,the density functional theory method is used to optimize its the geometrical parameters of the ground state under different external electric fields ranging from 0 to 0.04 a.u.(0-2.0569×1010V/m).The bond length,dipole moments,total energies and charge distributions are obtained.Based on the optimized structures,the CIS/B3LYP/6-311G**method at the same level as the above is adopted to calculate the UV-Visible absorption spectrum.The results show that the charge distribution has a significant change with the enhancement of the external electric field,which makes the bond length continuously increase,the total energy first increases and then decreases,the dipole moment first decreases and then increases.The strongest absorption peak is located at 246 nm in the UV-Visible absorption spectrum.With the enhancement of the extermal electric field,the absorption peak takes a significant blue shift or red shift,but the wavelength is still in the ultraviolet range.