Photodissociation dynamics of diiodomethane in solution

We have studied the photodissociation dynamics of diiodomethane (CH2I2) in aretonitrile by femtosecond pump-probe spectroscopy. The reaction was initi ated using 310 nm light and the transient absorption was measured over a sp ectral region from 290 to 1220 nm. The wavepacket leaves the initially exci ted Frank-Condon region on the CH2I2 potential surface on a timescale of 35 0 fs. The CH2I fragment is observed within the timespan of 03-3 ps. The hot photoproduct, assigned to be the isomer of diiodomethane CH2I-I, appears w ith a characteristic time of 1 ps and vibrationally relaxes on a timescale of 10 ps. (C) 1999 Elsevier Science B.V. All rights reserved.