EFFECT OF THE LASER TRANSVERSE SPATIAL DISTRIBUTION ON MULTIPHOTON IONIZATION PROCESSES

In this paper, the dependence of the photoionization cross section \sigma₂, total ion number N_i and the FWHM of photoionization spectral line in resonant multiphoton ionization processes (RMPI) upon the parameter C of the laser transverse spatial distribution has been studied. Considering the effects of spatial coordinate on the resonant multiphoton absorption cross section \sigma₁, the limited dimension of the laser-molecular interaction volume and threshold of laser intensity for RMPI, we deduce the expression of \sigma₂ vs the parameter C. We calculated the value of \sigma₂ for (2+2)PI of benzene by numerical method, and com-pared the result with that obtained by Bruzzeste et al. In additon, we also present the total ion number of photoionization and the FWHM of photoionization spectral line as a function of the parameter C.