Abstract

Laser fluorescence excitation of the HNF molecule, and its isotopomer DNF, have been detected in the ${\tilde{\text{A}}}^2{\text{A}}^{\prime }-{\tilde{\chi }}^2{\text{A}}^{″}$ band system for the F + HN₃ (DN₃) reaction. This observation indicates this reaction forms HNF + N₂, in addition to the well known HF + N₃ products. To our knowledge this is the first report of laser fluorescence detection of this molecule, for which the ground and excited electronic states form a Renner–Teller pair with bent equilibrium internuclear geometries. The K structure of the bands is observed to become simpler with increasing bending excitation, reflecting the reduction in the highest observable K′ levels. Decay lifetimes were measured for a variety of excited levels. The decay rate was observed to increase abruptly at an energy 23,800 ± 500 cm⁻¹ above the $\text{HNF}\left(\tilde{\chi }\right)$ zero-point level. This threshold is tentatively assigned to the onset of a predissociation channel. The excited state dynamics of HNF (DNF) will be compared with the dynamics of the well-studied Renner–Teller molecules HCO and HNO.

© 1992 Optical Society of America