Prediction of a Non-Valence Temporary Anion State of (NaCl).

The equation-of-motion coupled cluster method is used to characterize the low-lying anion states of (NaCl) in its rhombic structure. This species is known to possess a non-valence bound anion of A symmetry. Our calculations also demonstrate that it has a non-valence temporary anion of B symmetry, about 14 meV above threshold. The potential energy curves of the two anion states and of the ground state of the neutral molecule are reported as a function of distortion along the symmetric stretch normal coordinate. Implications for experimental detection of the temporary anion state are discussed. The sensitivity of the results to the inclusion of high-order correlation effects and of core correlation is examined.