A new process of negative ion formation―II

Abstract

It has been known for many years that negative ions are formed in various gases through which a stream of electrons is passed. It has generally been believed that these negative ions are all formed by one of two processes, which may be termed the “radiative process” and the “dissociation process". The latter process can occur only in a molecular gas, whereas the radiative process can occur in monatomic as well as molecular gases. In the dissociation process the impinging electron dissociates the molecule and attaches itself to one of the products of dissociation, the energy of the electron in excess of that necessary for dissociation together with the electron affinity of the resulting negative ion being carried away in kinetic form by the products of dissociation. The radiative process is a direct attachment of the electron to the atom or molecule without dissociation, the kinetic energy of the electron together with the electron affinity of the atom or molecule being radiated.