Low-lying electronic states of osmium monoxide OsO

The ground state of osmium monoxide (OsO) has long been controversial. In this paper, the low-lying Lambda-S and Omega electronic states of OsO have been comprehensively studied by the high-precision multi-reference calculations. The ground state of OsO is unexpectedly the closed-shell (1)Sigma(+) state with a double bond instead of the previously reported (3)Phi or (5)Sigma(+) state; after including the spin-orbit coupling effects, the ground state becomes (3)Pi(2). With the help of the theoretical spectroscopic constants and transition dipole moments, the emission spectra in the region of 405 nm-875 nm are assigned. Our results will facilitate the future studies of absorption and emission spectra of OsO.

Automated summary

In this study, the ground state of osmium monoxide (OsO) was investigated using high-precision calculations. The unexpected discovery of the true ground state will have significant implications for future studies on the spectroscopic properties of OsO.