不同方向外电场下SiF2分子激发特性

以6-311++g**(3df,3pd)为基组,采用B3P86方法研究了SiF2分子在y、z轴方向的外电场(－0.05~0.05 a.u.)下的几何参数、能量、电子结构和能级;在此基础上,采用CIS-B3P86方法研究了外电场下分子的激发特性.结果表明:分子基态参数随电场变化明显.如z方向电场使键长和偶极矩不断减小,总能量先减少后增加,能隙不断减少.激发态的激发能和激发波长随外电场大小和方向变化明显,振子强度受电场方向的影响从而改变了分子的跃迁性能.

Study on excitation characteristics of SiF2 molecule with external electric fields in different directions

A density functional method(B3P86) with 6-31++g**(3df,3pd) basis sets has been used to study the geometric parameters, total energies, electronic structure and energy levels with the external electric field (－0.05~0.05 a.u.) along the y-and z-axe direction; On the basis of optimized configuration, the excitation properties of molecules are calculated by the configuration interaction singles(CIS-B3P86) method with external electric field. The results show that thegeometric parameters of molecules change obviously with the electric field. Such asexternal electric field in zdirection makes the bond length and dipole moment decrease, the total energy first decreases and then increases, and the energy gap decreases. The excitation energy and wavelength of the excited state change obviously with the size and direction of the external electric field, and the oscillator strength is affected by the direction of the electric field, which changes the transition performance of the molecule.