| With the development of laser technology,the role of the laser on the atom,the internal electrons of the molecule has reached or even exceeded the Coulomb effect perceived by electrons.Electrons in such a strong laser electric field,the atoms,molecules of electrons in a very short period of time to get enough energy to get rid of the parent ion bound ionization.Strong field atoms,molecular interactions generated by the threshold of ionization,non-sequence ionization process has become the focus of attention.Theoretical studies In the ionization process,a potential function is usually chosen to describe the interaction of electrons with nuclei and other electrons.In this paper,the functions of different potential functions and the photoelectron emission spectra under different molecular collimation conditions are studied by the classical scheme.The function of the potential function in the process of ionization and re-collision is analyzed.Specific research includes the following three aspects:The influence of different soft-core parameters on the photoelectron emission spectrum in atomic potential function is analyzed.It is found that the momentum component of the photoelectron emission spectrum increases gradually with the increase of the numerical value of the atomic nucleus under the same linearly polarized incident laser pulse(perpendicular to the laser polarization direction).Through the analysis of the particle trajectories,it is found that the main source of theparticles with the lateral momentum close to zreo in the photoelectron spectrum is the direct ionization electrons.While the electrons in the photoelectron spectra are mainly derived from the heavy scattering electrons.Due to the more concentrated initial momentum distribution of the particles with larger parameters,the ionization electrons return to the parent ions,and the lateral momentum is obtained under the action of the Coulomb potential function,so that the components of the larger transverse momentum in the photoelectron emission spectrum Bigger.The photoelectron emission spectra of the molecular ion at the angle between the polarization direction of the incident laser and the molecular axis are analyzed.It is found that the photoelectron emission spectrum is symmetrical in the direction perpendicular to the polarization direction of the laser when the polarization direction of the laser is parallel to the molecular axis.As the angle between the polarization direction and the molecular axis increases,the photoelectron distribution exhibits asymmetric characteristics.Photoelectrons are mainly distributed in the molecular axis direction and laser polarization direction.The analysis of the ionospheric trajectories reveals that the reason for the generation of this photoelectron distribution is due to the interaction of the two nuclei in the molecular ion when the ionized electrons return to the parent ion,causing the electrons to produce an asymmetric momentum distribution.The electron correlation spectra of hydrogen molecules with the angle of polarization of the incident laser and the molecular axis are analyzed under the condition of ionization enhanced nuclear spacing.It is found that with the increase of the angle between the two,the electron correlation spectra are gradually distributed from the four quadrants to one or three quadrants.By analyzing the electron trajectory,it is found that the sequence ionization process plays a major role when the polarization direction of the laser field and the molecular axis are parallel,and the second electrons are ionized in multiple cycles after the first electron ionization.In the first electron ionization,the second electron obtains energy to resonate,the electronmotion range becomes larger,and ionization occurs near the peak of the subsequent laser field.When the incident laser polarization and the molecular axis are perpendicular,the non-sequence ionization process plays a major role,and the ionization occurs mainly in a period after the first electron ionization process. |
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