C-2 FORMATION IN VIBRATIONALLY EXCITED CO

The formation of C-2 has been observed following the vibrational excit ation of CO. Emission from four different electronic states has been o bserved: Swan bands (d (3) Pi(g) --> a (3) Pi(u)); Deslandres-d'Azambu ja bands (C (1) Pi(g) --> A (1) Pi(u)); Fox-Herzberg bands (e (3) Pi(g ) --> a (3) Pi(u)) and a Mulliken band (D (1) Sigma(u)(+) --> X (1) Si gma(g)(+)). The vibrational populations in the electronic states have been determined from low-resolution emission spectra. The time-resolve d behaviour of the emissions indicates that the upper states close to the dissociation limit are populated first, while the lower electronic states are populated following a time delay. Formation mechanisms are discussed.