将优化控制理论和多组态含时Hartree(MCTDH)方法相结合,建立了适合于MCTDH方法的计算具有平面结构的PTCDA分子的多自由度振动量子模型,研究了在PTCDA分子激发后从分子激发态回落至分子基态的动力学过程.在理论上分析了约化目标态产生率与激发脉冲、分子的演变时间及优化场的有效能量之间的关系,对分子在各个振动坐标下波函数的振动分布做了分析与比较.研究发现,增加分子的回落演变时间在提高目标态产生率的同时可以使优化激光控制场的强度降低,这为实验上用低能量激光最大程度地实现目标态提供了有效手段.
With the combination of optimal control theory and multi|configuration time-dependent Hartree(MCTDH)method,the vibrational quantum model for describing the multidimensional planar structural PTCDA molecule is constructed.Within the frame of MCTDH,the dynamics of PTCDA ground state via pump-dump process under an excitation of femtosecond laser pulse is considered.The relation of reduced control yield of target state to the shape of excitation pulses,the propagation time and the effective energy of optimal field are analyzed theoretically.The wavepacket distributions in the involved vibrational coordinates are compared with the vibrational parameters.It is found that with longer propagation time,higher control yield of target state at lower strength of optimal pulse is realized,which provides an effective method to realize the control with low energy laser pulses in experiment.