ABINITIO ADIABATIC AND DIABATIC POTENTIAL-ENERGY CURVES OF THE LIH MOLECULE

For nearly all states below the ionic limit [i.e., Li (2s, 2p, 3s, 3p, 3d, 4s, and 4p)+H] we perform the first adiabatic and diabatic studies. This treatment involves a nonempirical pseudopotential for Li and a full configuration-interaction treatment of the valence-electron system. Core-valence correlation is taken into account according to a core-polarization-potential method. We present an analysis of the diabatic curves and introduce appropriate small corrections accounting for basis-set limitations. For the low-lying states, our vibrational level spacings and spectroscopic constants are in excellent agreement with the available experimental data and with the best all-electron results. Experimental suggestions are given for the higher states.