Bromine halides: The neutral molecules BrClFn (n=1-5) and their anions - Structures, energetics, and electron affinities

Density functional methods were used for predictions of the structures and energetics of molecules and anions in the series BrClFn (n = 1-5). Very lit tle is known from experiment about these potentially important interhalogen molecules. Energy minima were found for all neutral molecules with the exc eption of BrClF5. However, the dissociation limits for ClF elimination from the BrClF3 (BHLYP and B3LYP only) and BrClF4 (all methods) molecules lie b elow the energy of the respective ground states. All the BrClFn anions are bound with respect to the corresponding neutrals; energy minima were found for anions up to BrClF5-. Structures of isomers with the chlorine atom in t he central position were also optimized. However, these local minima lie su bstantially above the bromine-centered structures, and the energy gap betwe en isomers grows with n. For the neutral molecules two paths of dissociatio n were found to possess the lowest energies, i.e., chlorine atom and ClF el imination. The latter channel becomes predominant at n > 1. For the anions the lowest energy dissociation pathways are Cl- or Cl elimination, but for n = 3, 5, ClF elimination becomes predominant. The adiabatic electron affin ities, the vertical electron affinities of the BrClFn,, molecules, and the vertical detachment energies of the BrClFn- anions were predicted in this w ork. The adiabatic electron affinities of the closed-shell BrClFn molecules significantly exceed those of the corresponding BrFn species, while for mo lecules with an odd number of electrons they are similar or slightly lower than electron affinities in the BrFn series. Many new experiments are sugge sted by this researcher, in light of the large predicted electron affinitie s and the fact that none of these has been measured in the laboratory.