Electron affinity. The zeroth ionization potential

Abstract

It is the purpose of this article to present the merits of adopting the terminology zeroth ionization potential to describe the energy change that occurs when a gaseous anion loses an electron.

The experimental values of atomic electron affinities. Their selection and periodic behavior

“…Since most atoms have more than one elec tron, it is customary to consider the energy for the formation of the monopositive ion as the first ionization potential, the energy for the formation of the dipositive ion from the monopositive ion as the second ionization potential, and so forth. In keeping with this practice, Brooks, Meyers, Sicilio, and Nearing (1) suggest that the energy change for the reverse of reaction (1) be designated as the zeroth ionization potential. A knowledge of atomic electron affinities and ionization potentials is necessary for the understanding of any phenomenon or reaction involving atomic ions in the gaseous, liquid, or solid phases.…”

“…lytical chemistry textbooks and have been discussed in several recent articles in this Journal (1-3). The electron affinity of an atom (A) is defined as the energy released when an atom and an electron react to form a negative ion in the gas phase at 0°K, i.e., the energy for the reaction A(g) + e = A_(g) (1) where T = 0°K; while the ionization potential is the energy required to remove an electron from an atom at 0°K. The atoms and ions are all assumed to be in their ground electronic state.…”

“…Several illustrative examples are: (1) in gases, ion-molecule reactions, electron impact and attachment phenomenon, and radiation chemistry; (2) in solution, radiation chemistry, kinetics and mechanisms of electrochemical processes, solvation energies, solution acidities, electron donor acceptor complexes, and the electronic spectra of negative ions; (3) in solids, the estimation of lattice energies, superconductivities, and the effects of radiation upon solids. In the theoretical area, experimental values can be used to test quantum mechanical calculations and various theories of electronegativities.…”

The Noble Gas Configuration - Not the Driving Force but the Rule of the Game in Chemistry

“…First, it is in keeping with the term's other uses such as proton affinity, which is positive if the addition of a proton to the target species is exothermic, and the binding affinity. Second, the treatment of electron affinity and ionization energies remains under the umbrella of one treatment with EA featuring the "zeroth ionization energy" (6). However, in order to make the bookkeeping in Born-Haber cycles somewhat easier, one may use the alternative quantity ∆H EA according to eq 4b.…”