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The photodissociation/photoionization processes of chlorobromomethane (CH_2BrCl) induced by fem- tosecond laser pulses have been investigated using pump-probe scheme combined with the time-of-flight mass spectra. The dominate photoproducts are observed at different delay time of the pump (400 nm) and probe (800 nm) pulses and the corresponding time-dependence of them is obtained. The results show that the decaying time of the molecule CH_2BrCl in the A-band is in the 100 fs. The decaying tendencies of the fragment ions (CH_2Cl~+ and CH_2Br~+) and the parent ion (CH_2BrCl~+) are almost the same and the relative ratios of the yields of them keep constant during the delay time of 0 to 150 fs. These facts suggest that the fragment ions come from the fragmentation of the parent ions in excited electronic states. The probabilities to form CH_2Cl~+ and CH_2Br~+ are obtained from the relative ratio of the ion intensity and are about 71.6% and 14.2%, respectively.
The photodissociation / photoionization processes of chlorobromomethane (CH 2 BrCl) induced by femtosecond laser pulses have been investigated using pump-probe combination combined with the time-of-flight mass spectra. The dominate photoproducts are observed at different delay time of the pump The results show that the decaying time of the molecule CH_2BrCl in the A-band is in the 100 fs. The decaying tendencies of the fragment ions (in nm) and probe (800 nm) pulses and the corresponding time- dependence of them is obtained. CH_2Cl ~ + and CH_2Br ~ +) and the parent ion (CH_2BrCl ~ +) are almost the same and the relative ratios of the yields of them keep constant during the delay time of 0 to 150 fs. These facts suggest that the fragment ions come from the fragmentation of the parent ions in excited electronic states. The probabilities to form CH_2Cl ~ + and CH_2Br ~ + are obtained from the relative ratio of the ion intensity and are about 71.6% and 14.2% respectively.