MASS-REDUCED QUANTUM NUMBERS - APPLICATION TO THE ISOTOPIC LITHIUM HYDRIDES (X1-SIGMA+)

The mass-reduced quantum number (MRQN) method of combining isotopic data is applied to the lithium hydride X 1Σ+ ground state. The ΔG(η) = μ1/2 ΔG(ν), B(η) = μB(ν), and D(η) = μ2D(ν) isotopically combined functions are obtained. An isotopically combined Rydberg-Klein-Rees (ICRKR) potential is constructed using the G(η) and B(η) functions. Evidence for breakdown of the Born-Oppenheimer approximation is presented and examined. The Dunham, Simons-Parr-Finlan, and Thakkar methods of potential expansion are also applied to lithium hydride and compared to the RKR potential. © 1979 American Institute of Physics.