The electronic spectrum of magnesium hydride and magnesium deuteride

The absorption spectra of MgH and MgD have been examined under high resolution and several new features observed. In the A 2 Pi -x 2 Sigma + transition the 0 P 12 satellite branch has been identified and assigned for both molecules. Measurements on the C 2 pi -x 2 sigma + system of MgH indicate that the C state is inverted with A= -3.7 cm -1 . The MgD absorptions at 236.4 nm and 236.0 nm, previously considered to belong to independent electronic transitions, have been shown to be, respectively, the P and Q heads of the 1-0 band of the C 2 Pi -x 2 Sigma + system. Rotational analysis yields the following constants for the C 2 Pi state of MgD; B e =3.256 cm -1 , D e =9.2*10 -5 cm -1 , beta e =0.25*10 -5 cm -1 , r e =0.1669 nm and Delta G( 1 / 2 )=1140.1 cm -1 .