Temperature Dependence of the Rate of Conversion of He+ into He2+

Abstract

Measurement of the decay of atomic and molecular emissions in the early helium afterglow for temperatures from 77° to 449°K and pressures from 3.76 to 9.93 Torr, together with the known value for the ambipolar diffusion of He⁺, have shown that the temperature dependence of the conversion frequency for the reaction He⁺+2He→He₂⁺+He goes as T⁻¹. When the conversion frequency is expressed as βp², the quantity βT³ is independent of temperature and pressure with an average value of 2.97×10⁹°K³sec⁻¹·Torr⁻². When the conversion frequency is expressed as k_R[He]², the quantity k_RT is independent of temperature and pressure with an average value of 3.19×10⁻²⁹°K·cm⁶ atoms⁻²·sec⁻¹. Theoretical considerations confirm that the temperature dependence of the conversion frequency goes as T⁻¹.