Electron Attachment to Aliphatic Hydrocarbons of the Form n-CNH2N+1Br(N = 2–6 and 8) II. A Swarm-Beam Study

Abstract

A swarm‐beam study has been made of brominated hydrocarbons of the form n‐ C N H 2N+1 Br (N = 2–6 and 8) . At energies below ∼ 3 eV the abundant ion found in the beam study was Br−. The dissociative attachment cross section σ da (ε) peaked at 0.76, 0.74, 0.73, 0.70, 0.71, and 0.13 eV, and had peak values equal to 3.95, 4.14, 5.50, 6.13, 7.41, and 32.2 × 10−18 cm2 for N = 2–6 and 8 , respectively. A small decrease has been observed in the cross‐section width with increasing reduced mass M r of the R (= n − C N H 2N+1 )– Br molecules. This and the increase in σ da with M r are discussed within the resonance‐scattering‐theory treatment of dissociative electron attachment to diatomic molecules. For some of the molecules studied, potential energy diagrams for RBr and RBr−* and separation and autoionization lifetimes for RBr−* are given.