Study on Photochemical Reaction Channels of Acetone in the Range 243～263nm

The multi-photon ionization processes of acetone in the range 243～263nm have been studied using mass-resolved excitation spectra. From the analysis to the excitation spectra and the mass peak widths of CH3COCH3+, CH3CO+ and CH3+, the photochemical reactions of acetone in this range are suggested as follows. The CH3COCH3+ signals in the shorter wavelength range of λ<255.67nm are due to the (1+1) photon ionization channels of acetone via (S1, T1) state of acetone. The fragment ion CH3+ comes from the dissociation of parent ion CH3COCH3+. The non-resonance spectral structure of fragment ion CH3CO+ comes mainly from the ionization of acetyl (CH3CO) produced by one-photon dissociation of acetone via (S1, T1) state. We also deduced the IP of (9.696±0.004)eV for acetone from the spectra of CH3COCH3+.