Electronic structure, reactivity, and spectroscopy of dihydrides of group-IB metals
Résumé
Atomic pseudopotentials and highly correlated wave functions, including spin-orbit interactions, have been used to evaluate the electronic structure, stability, and spectroscopy of triatomic molecule MH2, with a metal M belonging to group IB (Cu, Ag, and Au). CuH2 and AuH2 have been recently observed by IR spectroscopy in solid hydrogen and bending anharmonic wave numbers have been assigned to these two systems. The AgH2 molecule has not been detected nor experimentally characterized, despite several theoretical works arguing on its stability. Our results confirm that the MH2 radicals have a metastable bent ground state separated from the dissociation into [M+H-2] ground state by barriers which have been evaluated to 1.43, 0.78, and 0.80 eV, for Cu, Ag, and Au compounds, respectively. These barriers are calculated smaller than in previous determinations but still large enough to stabilize the MH2 systems. Spectroscopic data are calculated for these radicals.