ION–ION RECOMBINATION COEFFICIENT: II. MEASUREMENTS IN OXYGEN–NITROGEN MIXTURES

Abstract

Ion–ion recombination coefficients were measured at pressures ranging from 50 to 800 Torr for four oxygen–nitrogen mixtures which had been passed through cold traps at temperatures just above the boiling points of the gas samples. The following values of α were obtained at 1 atm and 25 °C: in O₂, (2.00 ± 0.10) × 10⁻⁶ cm³/sec; air, (2.21 ± 0.10) × 10⁻⁶ cm³/sec; N₂ with 1% O₂, (2.24 ± 0.10) × 10⁻⁶ cm³/sec; N₂ with 0.001% O₂, (2.45 ± 0.15) × 10⁻⁶ cm³/sec. The observed pressure dependence of α followed that predicted by Natanson's theory.Considerably lower values of about 1.6 × 10⁻⁶ cm³/sec were found for untreated air, and a further reduction to about 1.4 × 10⁻⁶ cm³/sec was observed when surfaces, which had been coated with a colloidal suspension of graphite in alcohol, were present.