RADIATIVE LIFETIMES, FLUORESCENCE QUANTUM YIELDS AND PHOTODISSOCIATION OF THE C2N2 (A(1)SIGMA(U)(-)) AND (B-1-DELTA(U)) STATES - EVIDENCE FOR STERICALLY HINDERED, TRIPLET MEDIATED CROSSINGS TO THE (X-1-SIGMA(G)(-STATE()) GROUND)

C2N2 A(1) Sigma(u)(-) <-- X-1 Sigma(g)(+) and B-1 Delta(u) <-- X-1 Sig ma(g)(+) absorption, laser-induced fluorescence and CN photodissociati on fragment spectra have been measured between 230 and 206 nm. Photoph ysical properties of individual vibrational levels of both electronica lly excited states are reported. Radiative lifetimes, quenching rates and fluorescence and dissociation quantum yields have been measured fo r the A(1) Sigma(u)(-) state. All vibrational bands of the B-1 Delta(u ) state are pre-dissociative with a 100% yield to CN fragments. (C) 19 97 Elsevier Science B.V.