飞秒泵浦-探测激光场中NaI解离和电离的场依赖  

Field Dependence of Dissociation and Ionization of NaI in Femtosecond Pump-probe Laser Fields

作　　者：郭玮 陈晓芳[2] 路兴强 GUO Wei;CHEN Xiaofang;LU Xingqiang(College of Nuclear Equipment and Nuclear Engineering,Yantai University,Yantai,Shandong 264005,China;Institute of Molecular Sciences and Engineering,Institute of Frontier and Interdisciplinary,Shandong University,Qingdao,Shandong 266237,China)

机构地区：[1]烟台大学核装备与核工程学院,山东烟台264005 [2]山东大学前沿交叉科学青岛研究院分子科学与工程研究院,山东青岛266237

出　　处：《光子学报》2022年第12期64-74,共11页Acta Photonica Sinica

基　　金：National Natural Science Foundation of China(No.11704178);Natural Science Foundation of Shandong Province(No.ZR2021MA074)。

摘　　要：利用含时波包方法计算了NaI的基态、激发态和NaI+离子基态的态布居数,全面研究且定量分析了泵浦和探测激光参数对非绝热NaI分子激发、解离和电离几率的影响。结果表明:泵浦激光是分子激发和解离的唯一影响因素,而电离则受泵浦激光和探测激光的共同影响。解离和电离过程相互竞争和共存。弱场强、短波长、窄脉宽和长延时的激光场有利于解离,反之则有利于电离。通过调整激光脉冲的形式,可以控制激发、解离和电离选择。研究结果对分子光谱学具有重要价值,也有助于在实验上实现光学分子控制。With the advances in ultra-strong and ultra-short laser pulses,many research works have concentrated on the real-time control of molecular dynamics.Apart from plotting the wave packet dynamics data of the electronic state,the state population is also capable of reflecting the excitation,dissociation and ionization of molecules.By controlling the wave packet evolution,the state population can be manipulated,thereby facilitating the optical control over the molecular processes experimentally.NaI molecule is a reference molecule for monitoring wave packet evolution experimentally and theoretically because a crossing is present between two electronic states that are coupled in a nonadiabatic way.The wave packet moves periodically between the internal and external turning points,which induced the periodical change of the photoelectron spectrum.Many researches mainly investigated the photoelectron spectrum,the competitive ionization channel and the predissociation dynamics of the first passage through the crossing region.Although the photoelectron spectrum offers the significant plotting of the exited-state movement of wave packets and ionization yields,it is not enough to reflect the excitation,dissociation as well as ionization processes of molecules.Herein,this work focuses on the study of the respective parameter effects of pump and probe pulses on the probabilities of excitation and ionization,and the total probability of dissociation of NaI molecules,which are examined completely and quantitatively analyzed.State populations of the ground and excited states of NaI and the ionic ground state of NaI+are calculated by adopting a time-dependent wave packet method,because it has the intuition of classical mechanics,no lack of accuracy of quantum mechanics.By appropriately changing the laser parameters,the population on each state can be controlled,and so can the excitation,dissociation and ionization probabilities.The dissociation increases while the ionization decreases when the delay time is prolonged.The pump-probe

关 键 词：飞秒泵浦-探测激光场 解离几率 电离几率 态布居 含时波包法 

分 类 号：O431.2[机械工程—光学工程]