High level ab initio calculations on ClFn − (n=1–6): Recoupled pair bonding involving a closed-shell central ion

Publication date: 15 September 2017 Source:Computational and Theoretical Chemistry, Volume 1116 Author(s): Lina Chen, David E. Woon, Thom H. Dunning In this paper we complete our studies of the bonding in the ClF n +,0,− series, characterizing the structures and energetics of the ground and low-lying excited states of ClF n − (n =1–6) via coupled cluster calculations with large correlation consistent basis sets and interpreting the results of the calculations using concepts from generalized valence bond (GVB) theory. The chlorine anion is isoelectronic with the argon atom, possessing three 3p lone pairs. However, the electrons in Cl− are much less tightly bound than those of Ar, and it is thus possible for the fluorine atom to form recoupled pair bonds and recoupled pair bond dyads with the chlorine anion even if this is not possible with the argon atom. The calculated dissociation energies, D 0(F n −1ClF), for the anions are 28.9, 72.3, 12.5, 59.9, 4.5, and 38.8kcal/mol for n =1–6, and the adiabatic electron affinities, EA 0(ClF n ), are 2.25, 4.78, 3.29, 5.47, 3.80, and 5.43eV, respectively [CCSD(T)/RCCSD(T)/AVQ+Z]. Unlike the cation series, the ClF n − anions have competing dissociation channels, ClF n − →ClF n −1 +F− and ClF n − →ClF n −1 − +F, because of the similar electron affinities of the fluorine atom and some of the ClF n −1 species. The ClF2 − and ClF4 − anions dissociate to F− and (ClF, ClF3), while the remaining members...

Source: Computational and Theoretical Chemistry - August 9, 2017 Category: Chemistry Source Type: research