Theoretical study of low-lying electronic states of OsO＋

Quantitative Aspects of Gas-Phase Metal Ion Chemistry: Conservation of Spin, Participation of f Orbitals, and C–H Activation and C–C Coupling

“…In the case of the argon atoms of OsO + , we calculated that the ground state was either 6 Σ + , 4 Π, or 4 Φ (all lying within 0.1 eV of one another), with 4 Π 5/2 being favored once spin–orbit corrections were made. Subsequent calculations by Liu et al support this assignment . Clearly, formation of OsO + ( 6 Σ + ) is spin allowed from ground state reactants, but so are the 4 Π and 4 Φ states.…”

“…92 In all of these systems, because the neutral reactants and products have triplet spin states, a manifold of MO + electronic states can be formed by spin-allowed pathways. In the case of Os + , the reactants can evolve along potential energy surfaces having quartet, sextet, and octet spin (s 93 Clearly, formation of OsO + ( 6 Σ + ) is spin allowed from ground state reactants, but so are the 4 Π and 4 Φ states. Thus, the spin-forbidden reaction at low energies and the spinallowed reaction at higher energies can no longer provide a rationale for the two features observed in the reactions of Os + with O 2 , and similarly for Re + and Ir + .…”

Low-lying electronic states of osmium monoxide OsO

“…Both the RMS-CASPT2 and MS-NEVPT2 results show that the ground Λ-S state of OsO is the closed-shell [1] 1 Σ + whereas the first excited state [1] 3 Π is only one or two hundred wavenumbers higher in energy, thus the other candidate ground states [1] 3 Φ and [1] 5 Σ + in early DFT studies [6][7][8] are completely denied. The excitation energies of the higher Λ-S states by RMS-CASPT2 and MS-NEVPT2 are basically coincident, but the energy differences can be 0.2 eV (about 1600 cm −1 ) or even larger in some states, for example, [1] 3 Φ and [1] 5 Σ + .…”

“…However, the multi-reference methods are not black-box tools, which hinders their widespread applications. In a recent paper [1] we studied the low-lying electronic states of the osmium monoxide cation (OsO + ), and in the present work, we focus on the neutral OsO molecule because its emission spectra measured nearly 40 years ago [2] have not been assigned until now.…”

“…[1] 1 Σ + (WBI = 1.9), a one and a half bond in[1] 3 Π and [1] 3 Φ (WBI = 1.5), and a single bond in [1] 5 Σ + and [1] 5 ∆ (WBI = 1.2). The bond strength n is also reflected in the equilibrium bond length through an approximate Badger relationship n = |a|r −|b| e…”