A visible spectrum of jet-cooled rhodium monosulfide

The diatomic molecule RhS has been observed for the first time. It has been studied by high resolution laser-induced fluorescence spectroscopy in a supersonic molecular beam following reaction by laser-vaporized rhodium atoms with CS2 doped in He. Electronic, vibrational, and rotational data have been collected. The RhS ground state has 4Σ− symmetry with a second-order spin-orbit splitting X(4Σ3/2-)-X(4Σ1/2-) of 47.43 cm−1, indicating case (a) coupling at low J. Three bands in the 535-555 nm region have been rotationally analyzed and give a bond length in the ground state of 0.2059 nm. A vibrational frequency ωe ≈ 485 cm−1 is estimated from dispersed fluorescence measurements.