The multiphoton ionization of the Hg atom by the intense radiation of a ruby laser is studied over the wide range of pressures from 1 to 1600 Torr, comparing with the experiments on iodine vapour. The six photon process occurs at 1 Torr. The three photon process is experimentally found at the pressure of 200 Torr and over. The five photon process is shown to exist at pressures of 50 and 100 Torr. It is considered that metastable states of the Hg atom affect multiphoton ionization. In addition, the abrupt increase of charged particles is also observed at the optical breakdown.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.