Photodissociation dynamics of chloroiodomethane in acetonitrile studied byultrafast pump-probe spectroscopy

We have studied the photodissociation dynamics of chloroiodomethane (CH2ICl ) in acetonitrile by ultrafast pump-probe spectroscopy. The reaction was in itiated using a femtosecond pulse at 266 nm and the transient absorption wa s measured out to delays of 300 ps over a spectral region from 330 to 850 n m. The photo dissociation leads to formation and subsequent vibrational coo ling of a product species, which we suggest is the isomer of chloroiodometh ane, CH2Cl-I, likely produced via in-cage recombination between the nascent fragments CH2Cl and I.