Dissociative ionization of CH 2 Br 2 in 800 and 400 nm femtosecond laser fields

We experimentally demonstrate the dissociative ionization of CH 2 Br 2 molecules irritated by 800 and 400 nm femtosecond laser fields using time-of-flight mass spectra and dc-sliced ion imaging technology. Our results show that in both laser fields, CH 2 Br 2 can ionize to CH 2 Br 2 +, then CH 2 Br 2 + break one C Br bond to produce fragments CH 2 Br (+) and Br (+). The charge assignment is determined by the ionization energy of the fragments. Additionally, in 400 nm laser fields, the CH 2 Br 2 + can overpass a transition state to form an intermediate CH 2 Br Br +, then the intermediate break C Br bond to produce Br 2 or Br 2 + via elimination channel.