Molecular beam-laser induced fluoresence studies on the chemical reactions H+NO2→OH+NO and H+ClO2→OH+ClO have probed primary energy disposal into the OH product. In both cases, the gross results are interpreted in terms of linear rotational and vibrational surprisals. These experiments also allowed measurements of partitioning into the fine structure levels of OH. In each reaction, spin doublets are produced statistically, but there is a definite preference for one of the A-doublet components. For H+NO2→OH+NO, the effects of reactant rotation and translation on the energy disposal have also been investigated. These experiments indirectly yield the rotational excitation of the NO fragment and the orientation of this rotational vector relative to the OH rotation vector. The results reported here and previous dynamics experiments suggest a simple qualitative model for this reaction involving a planar HONO complex. The results for H+ClO 2→OH+ClO also suggest reaction through complex formation. We postulate that the complex HOClO, although never observed, is a thermodynamically stable molecule and is probed in this reactive potential surface. © 1978 American Institute of Physics.