Recombination of ground state halogen atoms. Part 2.—Kinetics of the overall recombination of chlorine atoms

Abstract

The kinetics of overall recombination of ²P ground-state chlorine atoms have been investigated by internsity measurements on the chlorine afterglow emission spectrum Cl₂(³II_ou⁺→¹Σ⁺_g). For Cl₂ or Ar as third body at total pressures near 2 torr, no evidence supporting a major recombination path via Cl₃ as an intermediate was found. The mechanism of homogeneous recombination could be represented by the simple reaction [graphic omitted] with k_3,M=½[M]^–1 d([Cl]^–1)/dt. Measurements of k_3,Ar from 195 to 500°K gave k_3,C;2= 10^15.1 exp(+1600 ± 600 )RT= 10^16.3(T/300)^{[–2.7 ± 0.5]} cm⁶ mole^–2 sec^–1 and k_{3, Ar}= 10^14.3 exp (+ 1800 ± 700/RT)= 10^15.6(T/300)^{[–3.0 ± 0.5]} cm⁶ mole^–2 sec^–1. Methods for the determination of rate constants for chlorine atom reactions in discharge-flow systems are discussed.