用含时波包法研究了三态阶跃型K2分子在强飞秒泵浦-探测激光场中脉宽对波包动力学过程的影响.研究表明激光场强较弱或者脉宽较短都可能不出现Autler-Townes分裂.波包的振荡周期随脉宽增长而增大,而振荡幅度随脉宽增长而减小.脉宽影响Rabi振荡,而Rabi振荡的变化又导致了基态和激发态布居数周期性变化.首次量化了脉宽对激发态布居数的影响,表明变化频率随着泵浦场强的增强而增大.研究表明调节激光脉宽可实现对态布居数的选择性分布,可以为实验上实现分子的光控制提供重要参考.%The dependence of the wave packet process of three-level ladder K2 molecules on pulse width was in-vestigated via time-dependent wave packet method. There is no Autler-Townes splitting in the photoelectron spectrum with weaker pump intensity or shorter pulse width. The oscillation period of wave packet increases with increasing pulse width, while the oscillation amplitude decreases with increasing pulse width. The pulse width af-fects Rabi oscillation, which leads to the periodical change of the populations of the electronic state. The effect of pulse width on the population of the excited state was quantified firstly, showing that the change frequency varies with increasing pump intensity. The results illustrate that the selective population of electronic state can be ob-tained by controlling pulse width, which provide some important bases for light manipulation of molecular proces-ses experimentally.
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