运用含时密度泛函理论和分子动力学非绝热耦合的方法,研究了水分子在不同脉冲长度的激光场中的电离和动力学行为.计算结果表明,选择适中的激光强度,在同一激光频率的情况下,激光脉冲长度越长,水分子的电离越强;在相同脉冲长度时,激光频率越高,水分子电离越强.此外,当激光频率处于分子共振频率范围内时,长脉冲激光能够增强分子的电离导致分子解离,从而导致电子分布更加集中.当激光频率小于分子共振频率时,长脉冲激光也能够增强分子的电离,从而导致电子分布的变化,但对离子运动的影响很小. The ionization and dynamic behavior of water molecules in laser fields with different pulse lengths were studied by means of time-dependent density functional theory and molecular dynamics non-adiabatic coupling. The calculated results show that the moderate laser intensity at the same laser frequency , The longer the laser pulse length, the stronger the ionization of the water molecules; the higher the laser frequency is, the stronger the ionization of water molecules is at the same pulse length.In addition, when the laser frequency is in the molecular resonance frequency range, the long pulse laser When the laser frequency is less than the resonance frequency of the molecule, the long pulse laser can also enhance the ionization of the molecule, resulting in the change of the electron distribution, but the influence on the ion movement is very much small.