Partition of Recombination Energy in the Decaying Rare-Gas Plasmas

Abstract

In the collisional-radiative electron-ion recombination regime, the energy liberated from each recombination is partly carried away by a third colliding free electron and partly transformed into radiation. The partition of the energy among the electrons and radiation is obtained by comparing the probability of electron collisional de-excitation at different atomic-energy states, calculated by using Gryzi\ifmmode \acute{n}\else \'{n}\fi{}ski's formulation, and the spontaneous transition probability of bound electrons to all lower states evaluated by using the sum rule of line strength and the central-field approximation. A recombination-dominated decaying plasma is produced by a discharge tube energized with a capacitor bank. After cessation of the discharge current, the electron density, electron temperature, and atom temperature are measured by using both microwave and electrostatic probes, the spectral-line ratio method, and a fast-rise-time resistance thermometer, respectively. The partition of the recombination energy under different conditions for He, Ne, Ar, Kr, and Xe gases is determined from a solution of the electron-energy equation. The experimental results are in good agreement with the theoretical predictions. The oscillator strengths of the resonance lines for the five rare gases are also presented.