外电场下溴化铯的分子结构和解离特性

Molecular structure and dissociation characteristics of cesium bromide in external electric field

利用Semi-empirical/PM6方法,研究了外电场(-0.015~0.035 a.u.)作用下溴化铯(CsBr)分子的基态结构、键长、总能量、偶极矩、电荷分布、能隙、红外光谱、以及势能面的变化规律。研究结果表明:在外电场作用下,CsBr分子结构发生明显的变化。随着Cs-Br键方向的外电场增大,分子键长、电偶极矩、电荷布居数、能隙均逐渐减小,而分子的总能量却逐渐增大,同时分子红外光谱的最强峰发生蓝移;而随着外加负向电场的增大,分子势能面降低,势垒逐渐变小直至消失。研究还发现强度为-0.015 a.u.的外电场会使Cs-Br键断裂而发生分子解离,这为大气层的保护提供了理论依据。

The ground state structure,bond length,total energy,dipole moment,charge distribution,energy gap,infrared spectrum and potential energy surface of cesium bromide(CsBr)molecule under the action of external electric field(-0.015-0.035 a.u.)are studied by using Semi-empirical/PM6 method.The results show that the molecular structure of CsBr changes significantly under the action of an external electric field.With the increase of the external electric field in Cs-Br bond direction,the molecular bond length,electric dipole moment,electric charge population and energy gap gradually decrease,while the total energy gradually increases,and the strongest peak of the molecular infrared spectrum appears blue shift.On the other hand,with the increase of the applied negative electric field,the molecular potential energy surface decreases,and the potential barrier decreases gradually and finally disappears.It is also found that Cs-Br bond of CsBr molecules will be broken under an external electric field with an intensity of-0.015 a.u.,leading to the dissociation of CsBr molecules,which provides a theoretical basis for the protection of the atmosphere.