Theoretical Study On Electronic Flux In HCCI Ions

The dynamics of electrons in atomic and molecular systems plays an important role in understanding many chemical reactions and biological processes.The time scale of electronic motion is in the order of attosecond(10~-1818 s).It is a dream of many scientists to observe the motion of electrons in real time and directly observe the processes such as the breaking and formation of chemical bonds.An important physical process caused by electron motion is ultra-fast charge migration.Even in daily life,when light stimulates certain systems,ultrafast charge migration occurs,causing efficient energy transfer processes in the system.The charge transfer phenomenon necessarily includes multiple electronic states with their associated correlation effects.Further studies of such phenomena can clarify important issues such as electron correlation and molecular orbital relaxation,and unravel into the microscopic nature of many physical,chemical,and biological processes.In terms of experiments,the rapid development of ultrafast research by domestic and foreign researchers over the past decade has made it possible to obtain sub-second femtosecond laser pulses and pulse trains.These ultra-fast pulses provide us a powerful tool to study the ultrafast process of atoms and molecules.For example,the attosecond pulses generated by the use of high harmonic generation method are used to study the electron’s dynamics and have made important progress recently.Combining time-resolved high harmonic generation technique and high-precision numerical simulation of the dynamic of electronic quantum states,people reconstruct the microscopic nature of the ultrafast charge transfer process in HCCI~+ions.In this paper,we use the Molpro quantum chemistry software to optimize the structure of HCCI+ions.We use the complete active space self-consistent field(CASSCF)method to solve the Schr?dinger equation for HCCI~+ions to obtain the details of the required two electronic states.Based on the energy levels and wave functions of the electronic states,the time-dependent Schr?dinger equation of the HCCI~+ion system can be further solved.The evolution of the electronic wave function of the system can be obtained and the single electron density can be obtained by integrating the many-electron wave functions.The evolution of the charge density of HCCI~+over time,the electron flow density and its evolution have been calculated,the ultrafast charge transfer observed in the experiment has been explained clearly,and further suggestions for optimization of the experiments are proposed.