The influence of (n-n ')-mixing processes in He*(n)+He(1s(2)) collisions on He*(n) atoms' populations in weakly ionized helium plasmas

摘要

The results of semi-classical calculations of rate coefficients of (n - n')-mixing processes due to collisions of Rydberg atoms He*(n) with He(1s(2)) atoms are presented. It is assumed that these processes are caused by the resonant energy exchange within the electron component of He*(n) + He collision system. The method is realized through the numerical simulation of the (n - n')-mixing processes, and is applied for calculations of the corresponding rate coefficients. The calculations are performed for the principal quantum numbers n, n' in ranges 4 <= n <= n' <= 10, and the atom and electron temperatures, T-a, T-e, in domains 5000 K <= T-a <= T-e <= 20 000 K. It is shown that the (n - n')-mixing processes can significantly influence the populations of Rydberg atoms in non-equilibrium weakly ionized helium plasmas with ionization degree similar to 10(-4). Therefore, these processes have to be included in the appropriate models of such plasmas. (c) 2007 Elsevier Ltd. All rights reserved.