Author Institution: Department of Chemistry, University of WaterlooEmission spectra of MgH and MgD have been investigated in the 8000−22000cm−1 region using a high resolution Fourier transform spectrometer. These molecules were generated in a furnace-discharge source, at about 900 K and 333 mA discharge current with magnesium and a mixture of Ar and H2​ or D2​ gases. The recorded spectra contain not only the well-known A2π−X2Σ+ transitions, but also the B′2Σ+−X2Σ+ transitions of MgH and MgD. We obtained data for v′′=2 to 9 for the ground state of MgH and v′′=3 to 13 for MgD. Analyses of the data is in progress, and will lead to improved potential energy curves for the X2Σ+ states of MgH and MgD. These results will be presented at the time of symposium