Fragment state correlations in the dissociation of NO⋅HF(v=1)

Abstract

The NO(v,J)-fragment population distributions and recoil energies were measured for the vibrational predissociation of NO⋅HF following excitation of the H–F stretch. Most of the available energy appears in NO vibration and/or HF rotation. There is little recoil momentum. All NO(v,J) fragments are formed with near δ-function recoil kinetic energies, correlated with HF fragments in a single rotational level. Two dissociation channels proceed with similar probability to produce NO(v=0) and NO(v=1). Only two rotational levels of HF are populated. One of the HF rotational states is correlated exclusively with NO(v=0) fragments, the other is paired with NO(v=1) fragments. Constraints on fragment angular momenta as well as energetics appear important for the dissociation dynamics. The presence of significant amounts of vibrationally excited NO fragments, in the absence of observable spectroscopic perturbations, implies that intramolecular vibrational redistribution proceeds as the dimer dissociates. The data support two possibilities for the NO⋅HF dimer bond energy: (1) D0=448±5 cm−1 with coincident pairs of fragments NO(v=0)+HF(J=12) and NO(v=1)+HF(J=8); (2) D0=1769±10 cm−1 with JHF=9 and 2, respectively.