Hydrogen Ions in the Positive Column of a Hydrogen Glow Discharge

Abstract

A mass-spectrometric technique has been applied to the investigation of the positive column of a hydrogen glow discharge. Ions emerging out of the tube are found to be composed of major components of H+ and H3+ ions and minor component of H2+ ion over a range of E / p (the ratio of electric field strength to pressure) from about 30 to 100 V/cm·mm Hg and in a pressure range from 0.2–1.6 mm Hg. The relative density of H+ ions decreases monotonically with increasing pressure from 57% at p = 0.2 mm Hg (E / p ≑ 100) to 36% at p = 1.6 mm Hg (E / p ≑ 30), while that of H3+ ions increases from 38% at p = 0.2 mm Hg (E / p ≑ 100) to 62% at p = 1.6 mm Hg (E / p ≑ 30). The H2+ ion density decreases with increasing pressure or with decreasing E / p and is less than 10% of the total ion over the pressure range investigated. It is then found possible to obtain collision frequencies of the reactions H2++H2→H3++H and H2++H2→H++H+H2 as a function of E / p, assuming that these collision processes predominate in the plasma.