时间延迟双色飞秒激光中H_(2)^(+)的解离动力学研究  

Dissociation dynamic study of H_(2)^(+) in time-delayed two-color femtosecond lasers

作　　者：王景哲 董福龙 刘杰 Wang Jing-Zhe;Dong Fu-Long;Liu Jie(Graduate School,China Academy of Engineering Physics,Beijing 100193,China;College of Physics Science and Technology,Hebei University,Baoding 071002,China)

机构地区：[1]中国工程物理研究院研究生院,北京100193 [2]河北大学物理科学与技术学院,保定071002

出　　处：《物理学报》2024年第24期107-114,共8页Acta Physica Sinica

基　　金：国家自然科学基金委员会-中国工程物理研究院联合基金(批准号:U1930403);国家自然科学基金(批准号:12022513,12404394)资助的课题.

摘　　要：通过数值求解薛定谔方程,计算了具有时间延迟的泵浦及探测飞秒激光联合作用下氢分子离子解离的时间演化动力学.研究发现,通过调节探测光的脉宽长度可以对解离过程进行有效的操控;同时,结合延迟时间依赖的离子解离动能谱,可以反演出解离过程中的电子与核的微观动力学行为.另外,基于能动量守恒发展了一个描述解离动力学的经典模型,该模型能够定性地预言延迟时间依赖的解离动能谱.利用离子动能谱对探测光频率的依赖关系,提出了一个重构离子核间距的含时演化的方案.In recent years,the rapid development of ultrashort pulse laser technology has made it possible to regulate the ionization and dissociation dynamics of atoms and molecules.Among them,the microscopic dynamics of molecular dissociation have always been a hot topic.The phenomenon of molecular dissociation,which is caused by the interaction between femtosecond intense laser fields and H_(2)^(+)molecules,has attracted widespread attention.Previous theoretical studies on the dissociation of H_(2)^(+)molecules mainly focused on studying its dissociation dynamics through numerical calculations,with relatively few theoretical models.This paper aims to establish a simple classical model to describe the dissociation dynamics.Firstly,this paper calculates the joint distribution of nuclear energy and electronic energy in the dissociation process of H_(2)^(+)molecules under the action of pump lasers by numerically solving the Schrödinger equation.The results prove that H_(2)^(+)molecules initially in the ground state are dissociated into H^(+)+H^(*)after absorbing a pump photon in the pump light field.Next,this paper studies the dissociation dynamics of H_(2)^(+)molecules in time-delayed two-color femtosecond lasers.We find that it greatly depends on the specific forms of the pump light and the probe light.By utilizing the dependence of the dissociation kinetic energy release(KER)spectrum on the time delay of the two-color femtosecond lasers,we retrieve the sub-attosecond microscopic dynamic behaviors of electrons and atomic nuclei in the dissociation process.Furthermore,we establish a classical model based on the conservation of energy and momentum to describe the dissociation dynamics.This model can qualitatively predict the ion dissociation KER spectrum depending on the time delay of the two-color femtosecond lasers.The electronic resonant transition between the molecular ground state and the first excited state caused by the probe light will affect the ion kinetic energy spectrum in the dissociation process.Namely,the ion

关 键 词：飞秒激光 氢分子离子 解离动力学 

分 类 号：O53[理学—等离子体物理]