Multistage ionization of iodine molecules in a dense gaseous medium

An investigation was made of the influence of the pressure of a buffer gas (N₂) on three-stage photoionization of molecular iodine. A tunable dye laser and a nitrogen laser were used to provide the photoionizing radiation. Broadening of the spectral photoionization lines on increase in the nitrogen pressure was observed. The nature of the dependence of the number of ions formed by one pulse on the nitrogen pressure was influenced strongly by the dye laser wavelength. The experimental dependences were used to calculate the rate constants of the relaxation processes occurring in iodine molecules in electronically excited states.