Hydrogen continuum in discharges in argon, nitrogen, and air with water vapor

Abstract

The plasma emission generated by a low-pressure, pulsed-periodic discharge in different gases containing a small amount of water vapor is studied. Broadband radiation is detected in argon, nitrogen, and air, as well as in their mixtures with water vapor. It is shown that this radiation has a maximum intensity at low water vapor concentrations, increases with the increasing specific energy input, and is attributed to the H₂(a³Σ_g⁺) → H₂(b³Σ_u⁺) transition of the hydrogen molecule. The emission spectra of water and hydrogen vapor, as well as mixtures of argon, nitrogen, and air with water vapor are presented.