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A four-state model considering the relative velocity distribution function for calculating the cross section of laserinduced collisional energy transfer in a Sr-Li system is presented and profiles of laser-induced collision cross section are obtained. The resulting spectra obtained from different intermediate states are strongly asymmetrical in an opposite asymmetry. Both of the two intermediate states have contributions to the final state, and none of the intermediate states should be neglected. The peak of the laser-induced collisional energy transfer (LICET) profile shifts toward the red and the FWHM becomes narrower obviously with laser field intensity increasing. A cross section of 1:2×10-12 cm2 at a laser field intensity of 2:17×107 V/m is obtained, which indicates that this collision process can be an effective way to transfer energy selectively from a storage state to a target state. The existence of saturation for cross section with the increase of the laser intensity shows that the high-intensity redistribution of transition probabilities is an important feature of this process, which is not accounted for in a two-state treatment. [ABSTRACT FROM AUTHOR]

By considering the relative velocity distribution function and multipole expansion interaction Hamiltonian, a three-state model for calculating the cross section of laser-induced quadrupole--quadrupole collisional energy transfer is presented. Calculated results in Xe--Kr system show that in the present system, the laser-induced collision process occurs for [?]4 ps, which is much shorter than the dipole--dipole laser-induced collisional energy transfer (LICET) process. The spectrum of laser-induced quadrupole--quadrupole collisional energy transfer in Xe--Kr system has wider tunable range in an order of magnitude than the dipole--dipole LICET spectra. The peak cross section decreases and moves to the quasi-static wing with increasing temperature and the full width at half peak of the profile becomes larger as the system temperature increases. [ABSTRACT FROM AUTHOR]