Molecular Photodissociation Dynamics.

Available from UMI in association with The British Library. Requires signed TDF. Bound to free emission associated with the H _2O/D_2O C ^1B_1to A ^1B_1 transition has been observed following two photon quantum state selected excitation of water, and the C^1B _1to A^1B _1 fluorescence excitation spectrum has been used to refine previous measurements of the C ^1B_1 to B^1A_1 heterogeneous predissociation rate. Resolved photofragment fluorescence excitation spectra for selected rotational levels N' of OD(A^2Sigma^+), v' = 0 have been recorded and simulated in a way that distinguishes crossing at the <{rm J}_sp{ rm a}{'}^2> dependent B^1A_1 to A^1B_1 Renner-Teller intersection from crossing at the B^1A_1to X^1A_1 conical intersection. The results show a correlation between N ' and the B to A quantum yield which indicates that direct dissociation trajectories are associated with high product rotation and that indirect "bending" trajectories lead to low product rotation. Hydrogen peroxide has been photolysed at 248 nm and the resulting OH(X^2Pi) fragments completely characterised by polarisation dependent laser induced fluorescence spectroscopy at sub-Doppler resolution. The OH(X^2Pi) fragments are vibrationally cold (< {rm f_{v}}> < 2%), rotationally warm (< { rm f_{r}}> ~eq 10%) and translationally hot (<{rm f_{t} }> ~eq 90%, v ~eq 4 kms^{ -1}). The spin-orbit distribution is approximately statistical but there is a slight inversion of the lambda -doublet population which increases with N to a maximum value of ~eq2.