Potential energy curves and vibrational levels of ground and excited states of LiAl

The potential energy curves (PECs) for ground electronic state (X1∑+) and seven excited electronic states (a3∏, A1∏, b3∑+, c3∑+, B1∏, C1∑+, d3∏) of LiAl are obtained using the multi-configuration reference single and double excited configuration interaction method. Equilibrium bond length Re, adiabatic excited energy Te and vertical excited energy Tv are obtained. It is shown that c3∑+ is an unstable repulsive state, A1∏ is a weak bound state and the others are all bound states. Predissociation can be found between b3∑+ and c3∑+ states. Eight electronic states are dissociated along two channels, Li(2S)+Al(2P0) and Li(2P0)+Al(2P0). And then PECs are fitted to analytical Murrell-Sorbie (MS) potential function to deduce the spectroscopic parameters:the Re is 0.2863 nm, ωe is 316 cm-1 and De is 1.03 eV for the ground state; the values of Tv of excited states are 0.27, 0.83, 1.18, 1.14, 1.62, 1.81 and 2.00 eV; the values of De are 1.03, 0.82 and 0.26, repulsive state, 1.54, 1.10, 0.93 eV, and the values of corresponding frequency ωe are 339, 237, 394, repulsive state, 429, 192, 178 cm-1. By solving the radial Schrödinger equation of nuclear motion, the vibration levels, inertial rotation constants (J=0) are reported for the first time.