A direct observation of non-RRKM behavior in femtosecond photophysically activated reactions

A nonstatistical behavior is observed in the photodissociation of two acyl cyanide compounds. The analysis reveals that the excited-state dissociation rate does not decrease with molecular size as much as statistical as statistical rate theory predicts. This suggests that a nonergodic system in which the available vibrational energy does not redistribute statistically among all modes before the bond breakage occurs.