Multiphoton Dissociation and Ionization of Ethylene Oxide

The multiphoton dissociation and ionization of ethylene oxide in a static cell were investigated in the range of 278-285nm. A tunable dye laser（Quanta-Ray PDL-2） was pumped by a frequency-doubled Nd: YAG laser （DCR-2A）and then was frequency doubled in a wavelenth extention （WEX-1） to generate UV photons. In the range of 278.00 to 285.00nm, eight peaks were observed, corresponding to 284.08, 280.35, 280.30, 280.22, 280.19 280.13, 280.05 and 279.32nm respectively. The power dependence of the ionization signal was measured at 284.08. 280.22, and 279.32 nm. The major peaks in the MPI spectra could be assigned to the 2+1 process of ¹D₂→¹P₁,（2P²）³P_J→（2P3P）³P_J, and ¹D₂→¹D₂ transition of the carbon atom formed under the UV irradiation. The mechanism of dissociation and ionization of ethylene oxide was also been discussed.