The attachment of very slow electrons to polyatomic molecules

Abstract

The attachment of very slow electrons (<0.2 eV) to polyatomic molecules is discussed with a model in which the s wave of the incident electron dominates; the mechanism of capture is a non-adiabatic coupling due to the velocities of the nuclei. The attachment may be made permanent by the dissociation of the transient negative ion formed, or by collisions in the gas. The model accounts for cases where the rate of attachment is large at room temperature (e.g. SF6) by the assumption of a virtual state of the incident electron. The model can also account for cases where the rate constant is small at room temperature, but becomes large when the target molecules are heated to a few thousand K.