APPLICATIONS OF DIATOMICS-IN-MOLECULES THEORY .I. PREDICTION OF STABLE LIH2 AND LI2H MOLECULES

The semiempirical diatomics-in-molecules approach developed by Ellison is applied to the molecules LiH2 and Li2H, both unobserved experimentally. For LiH2, an isosceles triangular 2A 1 state with the diatomic component Ha at its equilibrium internuclear distance is predicted most stable, bound by 13.5 kcal/mole with respect to Li+H2(1∑g+). A linear symmetrical 2∑u+ state of Li2H is stable by 19.6 kcal/mole with respect to Li+LiH(1∑ +). lonization energies, characteristics of potential surfaces, and fundamental vibrational frequencies are predicted for both molecules.