Σ + 7 and Π7 states of manganese hydride
1973; American Institute of Physics; Volume: 58; Issue: 5 Linguagem: Inglês
10.1063/1.1679441
ISSN1520-9032
AutoresPaul S. Bagus, Henry F. Schaefer,
Tópico(s)Catalytic Processes in Materials Science
ResumoAb initio self-consistent-field calculations have been carried out close to the Hartree-Fock limit for the high spin Σ+7 and Π7 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 Σ+7 ground state are De=1.57 eV (2.4 ± 0.3), ωe=1549 cm−1 (1548), re=1.780 Å (1.722), and Be=5.32 cm−1 (5.68). And for the Π7 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 Σ+7 state to be more ionic than the Π7 state, the dipole moments are computed to be 1.6 and 4.1 D, both +MnH−. The small dipole moment of the Σ+7 state is seen to be due to a large −MnH+ contribution from the nonbonding 8σ orbital (which is replaced by 4π in the Π7 state). The manganese atom 3d5 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 a single ionic bonding σ orbital.
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