VALENCE AND EXCITED-STATES OF LIH-

Valence and excited dipole-bound states of the LiH- anion are calculat ed with the recently developed electron-attachment equation-of-motion coupled-cluster technique. It is found that the first dipole-bound sta te of LiH- corresponds to the second dissociation channel LiH- --> Li- (S-1) + H(S-2). The second (excited) dipole-bound state of LiH- is bel ow the neutral ground-state potential energy curve only for some range of the LI-H internuclear distance. This state appears at bond lengths larger than approximate to 2.0 Angstrom and decays at Li-H distances longer than approximate to 4.2 Angstrom, where the dipole moment of Li H becomes smaller than the critical value of 2.5 D. The adiabatic elec tron affinity of LiH calculated at the coupled-cluster level with the iterative inclusion of all single, double, and triple excitations and a large atomic natural orbital basis set is 0.327 eV, almost matching the recently obtained experimental value of 0.342 +/- 0.012 eV.