The k3Π Valence State of CO

Abstract The high-resolution VUV k 3 Π( v = 2, 3, 5) ← X 1 Σ + ( v = 0) "forbidden" absorption bands of CO have been observed and rotationally analyzed in the wavenumber range 90 000-98 000 cm −1 , confirming the recent 3 Π assignment for the upper valence state given by Baker et al. ( Chem. Phys. 178 , 569-579 (1993)). It is also shown that the k 3 Π 2 ( v = 3) spin-orbit component is responsible for the indirect predissociation at J = 31 in the E 1 Π( v = 0) state, while the k 3 π 0 ( v = 5) spin-orbit component is responsible for the indirect predissociation at J = 7 in the E 1 Π( v = 1) state.