Energy transfer between electronically excited argon and nitrogen: A kinetic model for the 3371 and the 3577 Å laser emissions

Laser action of an argon–nitrogen mixture excited by an electron beam has been studied. We report laser action at 3577 Å, but also at 3371 Å. In previous kinetic models laser emission at 3371 Å was forbidden. In this paper we present a new kinetic model based on a total transfer reaction between Ar (4s) and N2(C 3Πu). The main feature of our model is to permit laser action at 3371 Å only if the excitation time is short enough. The experiments performed with a small electron gun possessing the required characteristics (risetime=1 ns FWHM=10 ns) permitted us to observe laser emissions at 3371 and 3577 Å. For strong cavity coupling the emission is more powerful on the 3371 line than on the 3577 Å line. The same experiments made with an electron gun of a larger energy and a longer excitation pulse exhibits only a laser emission at 3577 Å, in agreement with theoretical computations.