Temperature dependence of rate coefficients for thermal electron attachment reactions of CH 3Br, CF 3Br, and CF 3I

Abstract

Rate coefficients for electron attachment reactions of CH 3Br, CF 3Br and CF 3I have been measured as a function of temperature. Absolute rate coefficients were obtained at 293 K for SF 6, CH 3Br, CF 3Br and CF 3I; in units of cm 3 molecule −1 s −1 the values are 2.2 × 10 −7 for SF 6; 6.3 × 10 −12 for CH 3Br; 1.2 × 10 −8 for CF 3Br; and 2.2 × 10 −7 for CF 3I. Rate coefficients are reported for CH 3Br, CF 3Br and CF 3I at 293, 615, and 777 K from relative rate measurements by using SF 6 as a reference compound. Mass spectral analysis of product negative ions confirmed a dissociative attachment mechanism.