The Time-dependent Quantum Mechanics Simulation Of The Photoassociation Spectroscopy Of Diatomic Alkali Molecules

Molecular reaction dynamics is the cutting-edge science of the chemical physics research.With the modern physical and chemical analysis method,it studies the microcosmic dynamics and principle of the chemical reaction on the atomic and molecular level.It provides the dynamic information of an exothermic reaction system through examining the internal movement of molecules and the collision between molecules and atoms,so it can reveal the fundamental laws of chemical reaction,and finally reach the purpose of controlling the chemical reaction.Wave packet dynamics is an important branch of physical chemistry.Its theoretical framework is widely used in the research of field-matter interaction and molecular dynamics.It has been proven to be a very effective method in the study of the ionization dynamics and vibrational excitation of molecules in the strong laser fields.Time-dependent wave packet method has many advantages.It can not only improve the efficiency of numerical calculation,but also provide clear and intuitionistic images.In short,it provides a classical-like interpretation with the quantum precision.In addition,the time-dependent quantum wave packet method is especially suitable for the study on the system which evolves with time.In the last ten years,the laser-control-atom technology has made great progress,and even to be achieved the atomic Bose-Einstein condensate.These results continue to inspire scientists to explore the manipulation of neutral molecules,and even the capture and cooling problems of polar molecules.Ultracold molecule has become the research focus due to its important application in fields of quantum computing,ultracold chemistry,quantum information,etc.Among them,the photoassociation technology has been paid great attention by scientific research workers in the process of producing ultracold molecules.Especially,the heteronuclear alkali metal diatomic molecules have been extensively studied due to their susceptibility to field manipulation.In this paper,the photoassociation process of Na K and Na Rb molecular systems are simulated based on the time-dependent wave packet method,and the theoretical basis,calculation results and detailed analysis of photoassociation under different laser fields are given.First of all,we brirfly introduce the basic concepts such as molecular reaction dynamics,time-dependent wave dynamics,photoassociation dynamics,etc..Then,the basic theoretical basis about the numerical simulation of the photoassociation reaction is given,which mainly includes the basic theory of time-dependent wave package dynamics and the calculation method of some dynamic informations.Next,the photoassociation process of Na K and Na Rb molecular systems in different laser fields are simulated through solving the time-dependent Schrodinger equation by quantum wave packet method,and the results are analyzed in detail.The numerical simulation can not only reveal some regular effects of laser parameters on the population,but also give the higher number of particles in the ground electron state by adjusting these laser parameters.The last part is a general summary of the whole thesis and the outlook of the photoassociation dynamics.