Theoretical calculation of the low-lying electronic states of the LaH molecule

Abstract

The potential energy curves of the low-lying electronic states of the LaH molecule are reported via the CASSCF method with multireference calculations (single and double excitations with Davidson corrections). Twenty-four low-lying electronic states of the LaH molecule in the representation 2s+1Λ(+/−) below 20 000 cm−1 were investigated along with five lower electronic states in the Ω representation. The harmonic frequency ωe, the equilibrium internuclear distance Re, the rotational constants Be, and the electronic energy with respect to the ground state Te were calculated for these states. Twelve new electronic states are investigated in the present work for the first time that have not yet been observed experimentally. Using the canonical functions approach, the eigenvalues Ev, the rotational constants Bv, the centrifugal distortion constants Dv, and the abscissas of the turning points Rmin and Rmax were calculated for the investigated electronic states up to vibrational level v = 43.