Attachment and diffusion of thermal electrons in methyl bromide

The Cavalleri electron density sampling technique (1969) has been used to measure the rate of loss of thermal electrons in mixtures of CH 3 Br and H 2 at temperatures in the range 293-500 K. From these data attachment coefficients for thermal electrons in CH 3 Br have been derived with an uncertainty of less than +or-4% enabling the temperature dependence and activation energy to be determined. In addition the diffusion coefficient for thermal electrons in CH 3 Br at room temperature has been determined from which an estimate of the e - -CH 3 Br momentum transfer cross section has been made for energies less than 100 meV.