Negative Ion Formation in Sodium Chloride TrimerAn ab Initio Study

Abstract

The possibility of an excess electron binding to a sodium chloride trimer in the gas phase was studied at the coupled-cluster level of theory with single, double, and noniterative triple excitations with the six-term s, six-term p, and four-term d (aug-cc-pVDZ+6s6p4d) basis sets. It was found that two types of anions can be formed: dipole-bound anions and solvated-electron (SE) species. The global minimum on the ground-state anionic potential energy surface corresponded to the Λ-shaped anionic structure, the vertical electron binding energy of which was 7858 cm-1. It was also found that the energy of SE structures, which are locally geometrically stable yet thermodynamically unstable, was considerably higher than that of dipole-bound anions. However, their vertical electron detachment energies were significantly larger (i.e., 26 906 and 34 052 cm-1).