FEMTOSECOND ELEMENTARY DYNAMICS OF TRANSITION-STATES AND ASYMMETRIC ALPHA-CLEAVAGE IN NORRISH REACTIONS

In this Letter, we report studies of the femtosecond dynamics of trans ition states and asymmetric cr-cleavage in Norrish type-I reactions. S ystematically, we consider the dynamics of dissociation along two reac tion coordinates in methyl ethyl ketone and diethyl ketone, and compar e these results with those of dimethyl ketone and methyl chloro ketone . The concept of concertedness as the system moves away from the trans ition-state region is examined and the primary and secondary processes involved in the alpha-cleavage are resolved. We compare experimental results with theoretical predictions of impulsive and statistical mode ls.