Mass-reduced quantum numbers: Application to the isotopic lithium hydrides (<i>X</i> 1Σ+)

Abstract

The mass-reduced quantum number (MRQN) method of combining isotopic data is applied to the lithium hydride X1Σ+ ground state. The ΔG (η) =μ1/2 ΔG (v), B (η) =μB (v), and D (η) =μ2D (v) 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.