Role of multistage collisions of the second kind in a laser based on ionic transitions in mercury

A comparative analysis is made of the time characteristics of the radiation emitted as a result of visible transitions in Hg II and the results are given of mathematical modeling of the active medium of an ionic He–Hg laser. A good agreement is reported between the experimental and calculated data. The results of an analysis show that, under discharge conditions typical of lasing, the contribution of the multistage Penning reaction (involving collisions of metastable mercury and helium atoms) to the pumping of the active levels of Hg II during the afterglow is negligible compared with the contribution of impact-radiative recombination at λ = 567.7 nm and charge transfer at λ = 615 nm. The contribution of Hg²⁺ ions, formed as a result of thermal collisions of singly charged mercury ions and metastable helium atoms, is calculated to be ~ 5%.