High resolution photofragment translational spectroscopy studies of the near ultraviolet photolysis of pyrrole

The fragmentation dynamics of pyrrole molecules following excitation at many wavelengths in the range 193.3 1 (1)A(2) radiationless transfer and subsequent fragmentation on the 1 (1)A(2) PES, yielding 'fast' H atoms (and pyrrolyl co-fragments)-reminiscent of behaviour seen at longer excitation wavelengths where the 1 (1)A(2) PES is accessed directly. The second is assumed to involve radiationless transfer to the ground state, either by successive 1 B-1(2)->-1 (1)A(2)-> X(1)A(1) couplings mediated by conical intersections between the relevant PESs or, possibly, by an as yet unrecognised direct 1 B-1(2)-> X(1)A(1) coupling, and subsequent unimolecular decay of the resulting highly vibrationally excited ground state molecules yielding 'slow' H atoms (together with, most probably, cyanoallyl co-fragments).