外电场下BN分子的结构及性质

采用QCISD方法研究了BN基态分子在不同场强条件下的稳定构型及激发态性质。分析了外电场对BN分子键长、总能量、能级、谐振频率和红外谱强度以及对BN分子前10个激发态的激发能、振子强度等的影响。结果表明随着正向电场的逐渐增大, BN分子键长先减小后增大；分子总能量则先增大后减小；分子电偶极矩 增大；费米能级和能隙均减小。谐振频率及红外谱强度均随正向电场的增大而增大。由基态到第1激发态的波长减小，激发能增大，而基态至第2-10激发态的波长增大而激发能减小。

The Molecular Structure and Properties of BN under External Electric Field

The geometrical structures and excited state properties of BN under electric field are studied by using QCISD method. The electric field effects on the bond length, total energy, energy level, harmonic frequency, infrared intensity and the excited state properties of BN molecule are explored. The results show that with the increase of the external electric field, the bond lengths first decrease then increase, the total energies increase firstly, and then decrease. The dipole moments linearly increase and the energy gaps and Fermi levels decrease with the increase of the electric field. The infrared intensities and harmonic frequencies are proved to increase under the electric field. The wavelengths from ground state to the first excited state are found to increase while to the second until the tenth excited states are to increase. The excited energies from the ground state to the first excited state are increasing while to the second until tenth excited state are decreasing with the increase of the external field.