飞秒激光参数对非绝热耦合分子态布居的影响

Effect of Femtosecond Laser Parameters on State Populations of Nonadiabatic Coupling Molecules

利用含时波包法研究强飞秒泵浦-探测激光场中激光脉宽、波长和场强对非绝热耦合Na I分子各态布居的影响.波包在势能面上做周期性运动,周期约为1 000 fs.延时为200 fs时,波包第一次到达交叉区域分裂成两部分.波包在交叉区域的分裂情况影响各态布居.脉宽增长,Na I分子的激发概率增大,而解离概率减小.泵浦波长为共振波长318 nm时,激发概率最大.泵浦波长增长,Na I分子的解离概率减小.泵浦场强增大,激发概率增大,但解离概率不变.探测激光波长和场强不影响Na I分子各态布居分布.调节激光场参数可实现对波包运动的控制从而控制态布居的选择性分布.研究结果为实验上实现分子的光控制过程提供参考.

Influence of pulse width, laser wavelength and laser intensity on state populations of a Nal molecule driven by a pump- probe pulse was studied via time-dependent wave packet approach. Wave packet moves periodically with roundtrip time 1 000 fs. Wave packet bifurcates in crossing region firstly at delay time 200 fs, which affects state populations. Excitation probability increases and dissociation probability decreases with increasing pulse width. Excitation probability approaches the maximum at resonance pump wavelength 318 nm. Dissociation probability decreases with increasing pump wavelength. As pump intensity increases, excitation probability increases while dissociation probability does not change. Probe wavelength and probe intensity do not affect state populations. Wave packet motion and selective distribution of state populations can be achieved by adjusting laser parameters. It provides bases for realizing light manipulation of molecules experimentally.