Three body electron–ion recombination in molecular gases

Abstract

The rate constant for the recombination of electrons with positive ions, α (cm³ s⁻¹), has been measured at 292 K as a function of pressure in gaseous H₂O, NH₃, (CH₃)₂CO, CH₃C1, CO₂, and neo‐C₅H₁₂. In all cases α is found to increase with increasing gas density, N (molecules cm⁻³), and over the density ranges studied can be described by a combination of a two and three body process, i.e., α=α₂+α₃N. In the same order of the gases as given above, the values found for 10⁶ α₂ are 4.1, 5.6, 6.4, 7.1, 3.9, and 7.0 cm³ s⁻¹ and for 10²⁵ α₃ are 270, 69, 55, 26, 5.8, and 2.5 cm⁶ s⁻¹. The values of α₃ are discussed in the light of existing theory together with the known characteristics of electron neutral collisions in the gases studied.