Photodissociation dynamics of CH2BrCl at 234 nm

Abstract The photodissociation dynamics of CH 2 BrCl has been studied at 234 nm utilizing the molecular beam-imaging system. In the photolysis, the C–Br bond fission is observed exclusively. The internal energy of the Br( 2 P 3/2 ) channel consists of two parts which is caused by the interaction between σ * (C–Br) and σ * (C–Cl) surfaces. This separation is newly resolved and studied to unravel the effect of another chromophore. The energy separation of two peaks is 25 kJ mol −1 and the ratio of fast to slow one is 3.2. The fast part is interpreted in terms of a rigid impulsive model with no vibrational excitation and the slow part by a soft one with a little vibrational excitation, respectively. The energy gap is suggested to be due to an umbrella motion.