Theoretical Study On The Few-photon Double Ionization Of Helium Atom And Quantum Dot

With the development of free electron laser technology,the investigation of multi-electron dynamics and electron correlation by ultra-short and ultra-strong ultra-ultraviolet pulses is a hot topic in atomic and molecular physics.The study of multi-electron correlation effect is important to understand many phenomena such as superconductivity,molecular structure and chemical reaction.The two-photon double ionization(TPDI)of helium atom is the simplest multi-electron correlation system.Using the full-dimensional multi-electron quantum numerical simulation program developed by us,we study the double-ionization phenomena of the interaction between the super-strong and super-fast laser and the helium atom,and discuss the ionization process of the double-electron system and its electron correlation effect.We discuss the two-photon and three-photon ionization(3PDI)processes at fixed laser frequency and laser intensity,and compare the two-photon and three-photon double ionization in monochromatic and tow-color fields,the different roles of electron correlation in this process are analyzed.By analyzing the asymmetry of the emitting electrons,we reveal the correlation between the joint angular distribution of the photo-electrons and the electron correlation in the monochromatic field and the effect of the asymmetry parameter in quantum three-body physics.The results show that for sequential double ionization,the joint angle distribution is average,but for non-sequential double ionization with strong electron correlation,the asymmetry coefficient changes more,and the joint angle distribution is extremely uneven.Secondly,we discuss the emission direction and the energy and momentum distribution of the two electrons from the double ionization of helium atom in one dimension,and compare the double ionization of the double electron quantum dot,more profound understanding of the electron correlation effect in the double ionization process of the important role.The effect of electron correlation on the sequential and non-sequentil ionization is also confirmed.This study provides theory basis for further understanding of helium double ionization,and provides a reference for relevant experiments.It has potential value in the field of electron correlation effect.