The recombination of and ions with electrons in hydrogen plasma: dependence on temperature and on pressure of H2

Abstract

The recombination of and ions with electrons has been studied in a low-temperature, high-pressure flowing afterglow in a mixture of He–Ar–H2. At high H2 number densities and lower temperatures, ions are formed and the electron decay is controlled by their recombination with electrons (rate coefficient ). At lower H2 number densities, ions dominate the plasma and the decay is controlled by these ions (rate coefficient ). In the intermediate pressure regime the decay of the afterglow plasma depends on the ratio and both rate coefficients. In the experiment the overall effective recombination rate coefficient, αeff, as a function of the H2 number density was measured. Recombination coefficients and and the equilibrium constant, KC(T), were determined at several temperatures. The observed pressure and temperature dependences are in good agreement with thermodynamical data.