SubDoppler polarization spectroscopy of OH ejected by vibrational state-selected trans HONO((A)over-tilde1A"):: OH vector correlations, energy correlation between coincident OH,NO pairs, and energy transfer pathways

Specific vibrational states (0(0), 2(n), n = 1-4) of trans HONO((A) over tilde) are excited with a polarized tunable laser and selected rotational states of the ejected OH fragment are probed by subDoppler polarization spectroscopy. The fragment recoil velocity and vector correlations obtained from the analysis of the Doppler profiles are used to deduce the internal energy content of the coincident NO cofragment, and to elucidate energy transfer pathways. These findings, together with our earlier results, are interpreted in terms of an (A) over tilde state potential energy surface in which: (1) the N=O coordinate is coupled to the recoil O-N coordinate; (2) there is a bottleneck in the exit channel and an insignificant exit-channel energy barrier; (3) there is significant angular dependence of the minimum energy path between the recoiling fragments; and (4) there is a coupling of the N=O stretch (nu(2)) with the HON angle bending (nu(3)) vibration. (C) 1998 Elsevier Science B.V.