Laser-induced multiphoton and collisional ionizations in sodium-argon mixture

It is attractive to investigate the interaction mechanism between metal and rare gas atoms within ionization process, especially for the mixture of metal vapor and rare gas. In this paper, laser-induced breakdown spectroscopy is used to study the ionization and recombination kinetic processes in sodium-argon mixture. Sodium-argon excimer is formed by the atomic collision, and it plays an important role in the ionization process, sodium atoms on 3P state are produced after the dissociation of excimer, then multiphoton ionization happens, the electrons in plasma are accelerated to collide with argon atoms, electron-impact ionization of argon will take place, identified with time-resolved atomic emission spectrum. Population accumulate on 3D,4P, and 5S states after the recombination process of Na+ with electron, then most population will transit to 3P state mainly by collisional relaxation.