The Ground State and A2Π Excited State of Magnesium Deuteride

Abstract

The visible emission spectrum of MgD has been reexamined at high resolution. Published analyses of the A2Π → X2Σ+ system have been extended and the data have been combined with observations in the B′2Σ+ → X2Σ+ system to provide information on the ground state levels ν = 3, 4, 5, and 6 for the first time. The following molecular constants (in cm−1) have been determined—for the A2Π state: ωc = 1154.75, ωcxc = 16.675, Bc = 3.2190, Dc = 9.64 × 10−5 and for the X2Σ+ state: ωc = 1077.71, ωcxc = 15.92, Bc = 3.0306, and Dc = 9.39 × 10−5. The dissociation energies in the A2Π and X2Σ+ states have been estimated to be ~ 15 500 cm−1 and ~ 11 500 cm−1 respectively. The MgH/MgD isotope effect and the Λ doubling in the A2Π state are discussed.