Determination of the rate coefficients for the collisional excitation and de-excitation of the upper laser levels of Ar

The absolute concentrations of the argon-ion states of the configurations 3d, 4s, 4p, 4p′, 4d and 5s have been measured for a pulsed laser discharge whose plasma parameters have been previously determined. For the resonant levels, the measurements were made by a self-absorption technique and for other levels by absolute spectroscopic observations. Variations of the populations of these levels as functions of discharge current and filling pressure (i.e. electron temperature and density) permitted calculations of the total excitation and de-excitation rate coefficients due to electrons as functions of temperature for each laser level. For excitation, collisions with the fundamental and long-lived states were taken into account while, for de-excitation, superelastic, excitation and ionization collisions were considered.