外电场作用下二氧化硅分子的光激发特性研究

Effect of external electric field on the optical excitation of silicon dioxide

采用密度泛函B3P86和组态相互作用方法在6-311G**基组水平上计算了二氧化硅分子从基态到前5个激发态的跃迁波长、振子强度、自发辐射系数An0和吸收系数B0n(n=1—5).研究了外电场对二氧化硅分子激发态的影响规律.结果表明,随外电场强度增大,最高占据轨道与最低空轨道能隙变小,占据轨道的电子易于激发至空轨道.因而在外场作用下分子易于激发.

The transition wavelengths, oscillator strength, Einstein An0 and B0n coefficients of excitation of silicon dioxide molecule from ground state to the first five different excited states are calculated by employing density function theory B3P86 and single substitute configuration interaction approach with basis set 6-311G ＊＊ . The excited states of silicon dioxide molecule under different external electric fields are investigated. It is shown that the HOMO-LUMO gaps become smaller and the electrons of the occupied orbital are more apt be exited to the virtual orbital as the external electric field intensity becomes stronger. Thus the application of the external electric field facilitates the exitation of the SiO2 molecules.