Abstract
The HCO is detected with the glyoxal excited to the first electronically excited state at photon energies in the range 25 305-25 353 cm -1 , ≈3300 cm -1 above the S 1 origin. Enhanced production of fragment HCO is observed but with no systematic dependence on J and K is identified. Due to a great density of the S 0 states, the enhancement is attributed to a crossing between S 1 and T 1 .