The photodissociation of CH2Br2 (DBM), 1,1- and 1,2-C2H4Br2 (DBE) at 248 nm was investigated using product translational spectroscopy. The results show that DBM and 1,1-DBE undergo a simple C-Br bond fission with fragments recoiling anisotropically. When the laser energy increased from 10 to 40 mJ/pulse, the nascent products, CH2Br and CH3CHBr, absorbed an additional photon to produce the secondary Br atom. In contrast, 1,2-DBE dissociates into the triple products Br (fast) + Br (slow) + C2H4 in a concerted reaction. This is confirmed from the measured anisotropy of the products, which indicates that the reaction is completed in a fraction of rotational period. Following an asynchronous concerted reaction, the simulation for the triple products was derived with the P(E-t) distributions coupled by asymmetric angular distributions. The results are discussed in terms of the weakness of the C-Br bond strength in the beta-bromoethyl radical that a rapid scission of the second C-Br bond occurred asynchronously with the cleavage of the first C-Br bond along the n sigma* potential energy surface. (C) 2003 American Institute of Physics.