LOW-ENERGY-ELECTRON ATTACHMENT TO BROMINATED METHANES

The rate constants as a function of the mean electron energy from ther mal to about 2 eV at room temperature have been measured for electron attachment to CBr4, CHBr3, CFBr3, CF2Br2, CH2BrCl, CHBr2Cl, and CBrCl3 using the pulse-radiolysis microwave-cavity method combined with micr owave heating. The electron attachment cross sections, derived from th e rate constant data, all show maximum at zero energy with no noticeab le peak at higher electron energies. Based on the differences observed in the absolute magnitude of the cross sections among the brominated compounds as well as those between brominated and the corresponding ch lorinated methanes, a model for the dissociative attachment to bromina ted methanes has been presented. (C) 1997 American Institute of Physic s.