Velocity Map Ion-imaging Study on Ketene Photodissociation at 218 nm

Photodissociation dynamics of ketene at 218 nm has been investigated using the velocity map ion-imaging method. Both angular and translational energy distributions for the CO products at different rotational and vibrational states have been obtained. The 2+1 REMPI spectrum of CO products is also obtained. The results are as bellow: (i) CO products in the first two vibrational states ( v”=0 and v”=1 ) exhibit signiffcant rotational excitation. Furthermore the rotational excitation of CO at the v”=0 level is noticeably higher than that at the v”=1 level. (ii) It was found that the major photodissociation pathway of ketene at 218 nm is the CH2(a1A1)+CO(X1Σ+) channel, while the CH2(b1B1)+CO(X1Σ+) channel and the CH2 (X 3B1)+CO(X1Σ+) channel are also likely present. (iii) The anisotropy parameters b of CO different rovibronic states all appear to be larger than zero. No significant difference is observed at the two vibrational states. 30 Refs. In English