A new technique has been used for the measurement of electron attachment rate coefficients for the molecules, SF6, CF3Br, and CCl2F2 at temperatures between 48 and 170 K. The results demonstrate very clearly the strong effect that internal vibrational energy of the molecules has on the attachment process.

A series of measurements of the rate coefficient for the dissociative recombination (DR) of H + 3 has been recorded. A value of 7.8 ± 2.3 × 10 −8 cm 3 s −1 was found for ions that are vibrationally cold. This is somewhat smaller than that measured previously by this group. The difference is ascribed to aerodynamic effects which affected our earlier measurement that have been eliminated in the present work. Results for D + 3 and HCO + DR are also reported.

The dissociative recombination of KrH + and XeH + has been studied using a FALP-MS technique. KrH + is found to have a small recombination rate while that of XeH + is 8.3 × 10 −8 cm 3 s −1 at 300 K.