KF分子在外电场中的物理性质研究

Study of molecular structure and spectrum of potassium fluoride under the external electric fields

为了研究氟化钾的物理性质,本文采用密度泛函理论和含时密度泛函理论LSDA方法在6-311G基组水平上,研究了KF分子在不同外加电场(-0.02~0.02 a.u.)下的键长、能量、电荷分布、能级分布、能隙、红外光谱以及激发态的变化规律.结果表明,外加电场对KF分子的结构有较大影响,随着Z(F-K键)方向外电场的增加,KF分子的键长以及电偶极矩一直减小,总能量一直增大,能隙E G先增大后减小,同时KF红外光谱的最强峰发生蓝移,前10个激发态发生红移,另一方面,随着电场强度的增大,KF分子解离能增大,反之解离能减小.

In order to study the physical properties of potassium fluoride,the bond length,energy,charge distribution,energy level distribution,energy gap and infrared spectra of KF molecules under different applied electric fields(-0.02~0.02 a.u.)are investigated by density functional theory LSDA method at the level of 6-311G radical group.The results display that the applied electric field has a great influence on the structure of KF molecules.With the increase of the external electric field in the direction of Z(F-K bond),the bond length and electric dipole moment of KF molecules have been decreased,the total energy has been increasing,and the energy gap EG has been increased first and then decreased.At the same time,the strongest peak of the KF infrared spectrum undergoes a blue shift;The first 10 excited states are redshifted.On the other hand,as the electric field strength increases,the dissociation energy of KF molecules increases,and vice versa,the dissociation energy decreases.