Resonant two-photon ionization spectroscopy of jet-cooled RuC

Abstract

A resonant two-photon ionization study of the jet-cooled RuC molecule has identified the ground state as a Σ+1 state arising from the 10σ211σ25π42δ4 configuration. The Δi3 state arising from the 10σ211σ25π42δ312σ1 configuration lies very low in energy, with the Δ33 and Δ23 components lying only 76 and 850 cm−1 above the ground state, respectively. Transitions from the X 1Σ+, Δ33, and Δ23 states to the Π23, Π13, Φ33, Φ43, Φ31, and Π11 states arising from the 10σ211σ25π42δ36π1 configuration have been observed in the 12 700–18 100 cm−1 range, allowing all of these states to be placed on a common energy scale. The bond length increases as the molecule is electronically excited, from r0=1.608 Å in the 2δ4, X 1Σ+ state, to 1.635 Å in the 2δ312σ1, Δ3 state, to 1.66 Å in the 2δ36π1, Π3 and Φ3 states, to 1.667 Å in the 2δ36π1, Φ1 and 1.678 Å in the 2δ36π1, Π1 state. A related decrease in vibrational frequency with electronic excitation is also observed. Hyperfine splitting is observed in the 2δ312σ1, Δ33 state for the Ru99(I=5/2)12C and Ru101(I=5/2)12C isotopic combinations. This is analyzed using known atomic hyperfine parameters to show that the 12σ orbital is roughly 83% 5sRu in character, a result in good agreement with previous work on the related RhC and CoC molecules.