First Evidence of Rhombic (NaCl)2‐. Ab initio Reexamination of the Sodium Chloride Dimer Anion.

Abstract

The possibility of electron binding to sodium chloride dimers in the gas-phase was studied at the coupled cluster level with single, double, and noniterative triple excitations using aug-cc-pVDZ+6s6p4d basis sets. It was found that three kinds of anions can be formedquasi-linear dipole-bound, nearly rhombic quadrupole-bound, and linear solvated-electron anions. In contrast to the earlier results, it was found that the rhombic neutral dimer (which is the neutral global minimum) does bind an excess electron to form an electronically stable anion of quadrupole nature. The global minimum on the ground-state anionic potential energy surface corresponds to the dipole-bound anion of quasi-linear structure (NaCl···NaCl)- whose vertical electron binding energy is 12 051 cm-1. It was also found that solvated-electron structure (ClNa···NaCl)- is considerably higher in energy than the anionic global minimum but its vertical electron detachment energy is significantly larger (i.e., 21 306 cm-1). The nearly rhombic (Na...