CO分子在线性极化飞秒激光场中的TDDFT研究

摘要

We present a theoretical study on the ionization and excitation dynamics of CO in various linear-polarized laser fields with in the frame work of the time-dependent density functional theory (TDDFT), applied to valence electrons, coupled non-adiabatically with molecular dynamics of the ions. It is found that the stronger the laser intensity, the more the energies are absorbed by CO and the earlier the ionization takes place with more electrons emitted. Moreover, the bond length of CO is stretched associated with more violent contraction vibration. The dipole moment along the laser polarization is enlarged when the laser intensity is enhanced. This study on the influence of the polarization of laser pulse on the excitation of CO indicates that the ionization of CO is maximized and the contraction vibration becomes most violent when the laser is polarized along the molecular axis. Ionization is restrained when the polarization angle is increased and the dipole vibration shows a strong dependence on the laser polarization. Furthermore, it is found that the electron density surrounding the carbon atom is distributed along the molecular axis particularly when the dispersion of the electrons around the oxygen atom is greatly influenced by the laser polarization.%本文运用将含时密度泛函理论和分子动力学非绝热耦合的方法，研究了CO分子在不同强度、不同极化方向的激光场中的电离和动力学行为。研究发现，激光强度越强， CO分子吸收的能量越多，电离越早且电离越强， CO分子键长变长且伸缩振动越剧烈。此外， CO分子偶极矩的变化及峰值也随着激光强度的增强而增大。对激光极化方向的研究发现，激光极化方向沿着CO分子轴向时，分子的电离最强且伸缩振动最剧烈。当激光极化角增大时， CO分子的电离逐渐被抑制且电子的偶极振动对激光极化方向表现出较强的依赖性。此外研究还表明， CO分子碳原子和氧原子周围电子的弥散方式不同且与激光极化方向有关。