Knowledge Bank

The electronic spectrum of MnH has been examined in thermal emission from Mn/H2 mixtures in a King furnace using both photographic and Fourier transform techniques. Two systems have been studied at high resolution: an infrared system centered near 847 nm and a visible system in the blue near 480 nm. Rotational analysis of the 847 nm system shows it to be due to $as\Sigma -s\Sigma$ transition. The 480 nm spectrum, which is extremely complex with dense rotational structure, arises from $as\Pi -s\Sigma$ transition. The two systems have the same lower electronic state. While the MnH spectra appear relatively free of local perturbations the corresponding MnD spectra show a number of branch irregularities. Branches in both systems are broadened to differing extents through nuclear hyperfine coupling.