Multiple-photon dissociation of CH2CO, C2H4 and C4H6O3, fluence dependence of the production of CH2(ã) and C2(a)

Abstract Ketene and ethylene have been dissociated with radiation from a TEA CO 2 laser at pressures between 1 and 15 mTorr. Laser-induced fluorescence was utilized to make relative concentration measurements of CH 2 (a 1 A 1 ) and C 2 (a 3 H u ) yields (in the case of ketene) and of C 2 (a 3 H u ) yield (in the case of ethylene) at fluences between 1 and 100 J/cm 2 . The ketene dissociation was investigated at two different CO 2 frequencies corresponding to excitation in different normal modes. By the dissociation of acetic anhydride, CH 2 (a 1 A 1 ) is produced very efficiently.