Fourier transform spectroscopy of MnH and MnD: Rotational analyses of the 846 nm and 1060 nm systems

Two infrared band systems, centred near 846 nm and 1060 nm in both MnH and MnD have been rotationally analysed and shown to have a common lower state. The electronic transitions lie within the quintet manifold and are here designated c 5 Σ-a 5 Σ and b 5 Π i -a 5 Σ for the 846 and 1060 nm systems, respectively. In the 846 nm system in MnH all 10 main branches have been found in the 0-0 and 1-1 bands, while in MnD the data are complete only for 0-0. Satellite branches have been identified in the 1060 nm system and all spin and Λ-type doublings have been established. The number of assigned 0-0 branches in the 1060 nm system is 35 for MnH and 37 for MnD. Molecular constants have been determined for all three states involved. Λ-doubling diagrams are presented for b 5 Π i state with v = 1, 2 levels in MnH and with the v = 2 level in MnD. Local perturbations in c 5 Σ (v = 1) in MnH are suspected to originate from the v = 3 level of b 5 Π i .