The Orientation Of Linear Molecules In A Strong Laser Field Depends On Dynamics

When the strong laser field interaction with the atoms and molecules system,due to the external field is very strong,the effect of the external field can be compared with the coulomb.The laser field makes the potential energy of the atoms and molecules bend,and the electrons has a great chance to go through the barrier of the system.This process is accompanied by many interesting physical phenomena,such as high-order harmonic generation(HHG),high-order above-threshold ionization(HATI),nonsequential double ionization(NSDI)and so on.In the paper,we study the high harmonic generation and high-order above-threshold ionization with complex laser field and linear molecules.In the third chapter,we obtained photoelectron momentum distribution with different orientations and laser parameters by solved the time-dependent Schrodinger equation.Combined with the analysis of the strong field approximate model,it is found that the two-center interference of the molecules is obviously reflected on the momentum distribution spectrum of the electrons and have effect on the relative strength and half-width of the momentum distribution.Further analysis shows that the coulomb force the free electrons has an effect on the deflection of the momentum distribution.At the same time,we further calculate the momentum distribution of polar molecules with different orientations.It is found that the permanent dipole of polar molecules related to orientations leads to asymmetric ionization of electrons at different orientations.Based on the above studies on the photoelectron momentum spectrum,we provide a scheme about obtain the molecules orientations information experimentally.In the fourth chapter,we obtained harmonic spectrum about orthogonal two-color fields with different molecules orientations and laser field phase.By adjusting the phase,we realize the long and short orbit control in the process of harmonic generation.By studying the different orientations of H2+ harmonic spectrum,we found that the two-center quantum interference can enhance or inhibit the quantum tracks,and there are obvious for the interference effect on the harmonic spectrum.Based on the above conclusions,we put forward the use of orthogonal two-color fields in the polarization field orientation for 450 isolated linear molecule to achieve a single cycle of attosecond pulse scheme,and we provides a scheme about study the attosecond science experimentally.