THE INS AND OUTS OF COLLISION COMPLEXES

The lecture reviews some very recent developments in the experimental study of quantum state-resolved bimolecular reaction dynamics. The int roduction of polarised, Doppler-resolved laser spectroscopy into the t raditional pump-probe scheme, has provided a powerful new strategy, wh ich combines the scalar advantages of determining product state distri butions, with the vector advantages of determining product state-resol ved angular distributions. The new techniques have been applied to thr ee benchmark reactions, each of which proceeds through the intermediac y of a bound collision complex: O(D-1(2)) + H-2 --> OH(upsilon', j') H O(D-1(2)) + CH4 --> OH(upsilon', j') + CH3 H + CO2 --> OH(upsilon', j') + CO In each case, analysis of the new state-resolved data in the light of real-time measurements or of quasiclassical trajectory calcu lations, has clarified the dynamics of these 'complex' reactions.