Electronic spectroscopy of predissociative states of platinum oxide cation

The photodissociation spectrum of jet-cooled PtO+ is reported over the range of 25 000 to 30 000 cm−1. Excited state vibrational progressions are identified for 4Π−1/2 ← 4Σ3/2 and 4Π5/2 ← 4Σ3/2 transitions with several vibrational peaks rotationally resolved. Additional peaks not assigned to a vibrational series also exhibit rotational structure. Transitions arising from the 4Σ3/2 ground state show a spectroscopic onset of 25 520 cm−1, giving an upper limit to the bond strength of D0(Pt+–O) ⩽ 305 kJ mol−1. A hot band is observed at 25 317 cm−1 and rotational analysis predicts it as arising from a low-lying Ω=7/2 state, probably 4Δ7/2.