SrH_(2)分子在外电场作用下基态性质及激发特性研究

Study on Ground State Properties and Excitation Characteristics of SrH_(2) Molecule Under External Electric Fields

采用密度泛函理论,以DGDZVP为基组,采用wB97XD方法研究了不同外电场(0~0.05 a.u.)对SrH_(2)分子基态几何结构、电荷布局、偶极矩、总能量、最高占据轨道(HOMO)能级、最低空轨道(LUMO)能级及能隙(E_(g))、红外和拉曼光谱及电子激发特性的影响.研究结果显示:键长和偶极矩随外电场的增大而增大,键角、总能量、HOMO能级、LUMO能级和能隙随外电场的增大而减小,Sr原子正电性随外电场的增大而减弱,H原子负电性也随外电场的增大而减弱,红外和拉曼光谱在外电场的作用下都出现了红移,其强度也发生了明显的变化,前26个激发态激发能、振子波长和振子强度都随外电场变化而发生了比较复杂的变化,说明SrH_(2)分子光谱和激发特性均易受外电场的影响,这对材料的光学特性研究提供理论参考.

The effects of different external electric fields(0~0.05 a.u.)on the ground state geometry,charge layout,dipole moment,total energy,HOMO energy level,LUMO energy level and energy gap(E_(g)),infrared and Raman spectra and electronic excitation characteristics of SrH_(2) were studied by wB97XD/DGDZV method.The results show that the bond length and dipole moment increase with the increase of the external electric field,the bond angle,total energy,HOMO energy level,LUMO energy level and energy gap decrease with the increase of the external electric field,the positive electricity of Sr atom decreases with the increase of the external electric field,and the negative electricity of H atom decreases with the increase of the external electric field,while the infrared and Raman spectra have a red shift under the action of the external electric field,and their intensity has also changed significantly.The excitation energy,the oscillator wavelength and oscillator strength of the first 26 excited states have complex changes with the change of external electric field,which shows that the spectrum and excitation characteristics of SrH_(2) molecule are easily affected by the external electric field,providing a theoretical reference for the study of optical properties of materials.