Abstract
Excitation rate coefficients for the 1, 1, 1, and 1 levels of argon by collisions with low-energy electrons have been measured using a drift-tube technique. Time dependences of the absolute population densities of the excited levels were measured by an absorption method with a tunable diode laser as a light source. The absorption data were analyzed according to the rate equations for these levels and the excitation rate coefficient per unit length of electron drift and per argon-atom density was obtained for each level as a function of the electric field to gas density ratio E/N. The values for the 1 level vary from 2.0× to 2.5× as E/N increases from 5× to 5× V . In comparison with these values, those for the 1 level are about one-fifth, those for the 1 level are about the same, and those for the 1 level are slightly larger in respective measured E/N ranges. In order to estimate the cascading effects from the higher-lying levels, excitation rate coefficients for the 2p and 3p levels have also been measured from absolute intensities of the line emissions. From a comparison of all the measured values of the excitation rate coefficients with those calculated from the Boltzmann analysis, a recommended set of cross sections for these levels has been deduced.
- Received 13 March 1986
DOI:https://doi.org/10.1103/PhysRevA.34.1007
©1986 American Physical Society