Infrared multiphoton dissociation of acrolein. Time-resolved observation of CO(v = 1) IR emission at 4.7 µm

In contrast to the photochemistry of electronically excited acrolein producing vinyl and formyl radicals via C---C bond rupture, multiphoton vibrationally excited molecules undergo concerted dissociation generating CO and ethylene. Vibrational excitation in the CO product is detected immediately following the CO2 laser pulse by observing IR emission at 4.7 µ m. The decay of the IR emission was studied as a function of acrolein pressure. A vibrational-vibrational relaxation rate constant of CO (v=1) by acrolein is found to be 1240 ± 200 Torr-1 s-1