Theoretical study of the electronic structure of the low-lying states of the Li2H molecule

Results of a complete active space self-consistent field treatment of the two lowest states of each symmetry 2A1, 2B1, and 2B2 of Li2H are reported. An isosceles triangle is predicted for the equilibrium geometry of the ground state (1)2A1 (RLiLi = 2.48 Å, RLiH = 1.70 Å) (1 Å = 10−10 m) and of the excited state (1)2B1 (RLiLi = 2.91 Å, RLiH = 1.58 Å) while a linear geometry is predicted for the (1)2B2, (2)2A1, (2)2B2, and (2)2B1 states with the following values for RLiH = RLiLi/2: 1-66, 1.57, 1.66, and 1.57 Å, respectively. Fitted analytical forms of the potential energy surfaces for the six states investigated are also displayed.