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

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+1)Lambda((+/-)) below 20 000 cm(-1) were investigated along with five lower electronic states in the Omega representation. The harmonic frequency omega(e), the equilibrium internuclear distance R-e, the rotational constants B-e, and the electronic energy with respect to the ground state T-e 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 E-v, the rotational constants B-v, the centrifugal distortion constants D-v, and the abscissas of the turning points R-min and R-max were calculated for the investigated electronic states up to vibrational level nu = 43.