^{7}Σ^{+} and^{7}∏ states of manganese hydride

## Abstract

Ab initia self-consistent-field calculations have been carried out close to the Hartree-Fock limit for the high spin 7Σ+ and 7∏n electronic states of MnH. Five different hydrogen-centered basis sets of Slater functions are tested for H~ and MnH. Predicted spectroscopic constants (with experimental values in parentheses) for the 7Σ+ ground state are De= 1.57 eV (2.4±0.3), ωe= 1549 cm-1 (1548), r e= 1.789 Å (1.722), and Be= 5.32 cm-1 (5.68). And for the 7∏ state, Te=21 870 cm -1 (17 700), ωe=1708 cm-1, re= 1.703 Å, and Be= 5.88 cm-1 (6.43). The electronic structure of the two states is discussed with respect to the contributions of the different molecular orbitals to the electric dipole moment and population analysis. Although the population analysis predicts the 7Σ + state to be more ionic than the 7∏ state, the dipole moments are computed to be 1.6 and 4.1 D, both +MnH-. The small dipole moment of the 7Σ+ state is seen to be, due to a large -MnH+ contribution from the nonbonding 8σ orbital (which is replaced by 4π in the 7∏ state). The manganese atom 3d6 configuration survives essentially unchanged in both states of MnH, and it is suggested that the electronic structure of other transition metal hydrides may be quite similar, involving.