分子对飞秒激光场响应的含时密度泛函理论研究
Time-dependent density functional theory studies of molecule responding to femtosecond laser field

采用含时密度泛函理论方法研究线性分子碳化锂（Li2C2）对飞秒激光场响应的电子-离子动力学行为。在典型的近共振和非共振的激光频率作用下，分别对比分析了分子的共振和非共振电离过程。研究发现：分子在共振频率激光场的作用下发生更强的电离过程，并倾向于发生库伦爆炸，键长的振荡断裂与电离相互促进影响，而分子在较弱的激光场作用下发生单光子电离过程；随着双脉冲时间间隔的增加，离化电子数在一定范围内呈振荡上升趋势，随后趋于常数。
The electron-ion dynamics of optical response in simple linear molecule Li2C2 induced by femtosecond laser is studied in the framework of time-dependent density functional theory (TDDFT), which self-consistently couples a quantum mechanical treatment of valence electrons and a classical molecular dynamical description of ionic cores. The on- and off-resonant photoionization are investigated in the process of laser-molecule interaction. The laser with on-resonant frequency induces pronounced enhancement in electron ionization. And the coulomb explosion of molecule is preferred to occur in the on-resonant case, in qualitative agreement with previous theoretical investigations. Moreover, bond length oscillation and bond breaking leading to an increase of ionization is observed. The single-photon ionization phenomena is observed under weak laser intensity. Finally, ionization electron curve increases with oscillation with the increase of separation time between double pulses.