Effect of autoionizing states with a high-lying spectator electron on population inversion of nitrogen plasma in recombining phase

Abstract

Discharge produced plasma (DPP) is a promising tool to generate effective extreme ultraviolet (EUV) light. A hydrogen-like nitrogen ion emits light at 13.4 nm with an optical allowed atomic transition from n = 3 to 2, where n stands for a principal quantum number. We focus on the properties of population inversion between n =3 and 2 in recombining phase. Population inversion is calculated in the framework of population kinetics, and a gain coefficient G is estimated. In this study, dielectronic-capture ladderlike (DL) processes are included. At high density and low temperature, the DL deexcitations make a large contribution to the population inversion.