Microwave determination of the coefficient of dissociative recombination of Ar₂⁺in Ar afterglow

The coefficient of dissociative recombination of Ar 2 + ions at 300 K has been determined as (8.2+or-0.5)*10 -7 cm 3 s -1 by means of computer fitting of the rate equation with results of measurements of the absolute electron density in the afterglow. The present value compares well with previous data and gives insight into the temperature-dependence of the coefficient. The authors have developed a technique to determine two calibration factors of the microwave cavity, the geometrical factor K d and the effect of deformation of the cavity field due to the presence of a glass envelope. The absolute number density of electrons has been determined using the calibrated microwave cavity. The calibration factors have been confirmed by Langmuir probe measurements.