An analysis of the hydrazine—fluorine flame. The A2A′-X2A]″ emission spectrum of HNF and its relation to other HAB co

The chemiluminescent reaction N₂H₄ + F₂ is shown to be dominated by visible emission from NH* (A³Π-X³Σ^?), HNF^* (A²A′-X²A″) and vibrationally excited HF2(X¹ Σ⁺). Possible mechanisms for formation of these species are discussed with reference to previous results from similar flame reactions. The A–X emission spectrum of HNF contains the heretofore unreported progression (0, 0, 0) → (0, υ₂^″, 0) to vibrational levels υ₂^″ = 0–3 of the X²A″ state. Each vibrational transition shows well resolved K-type subbands characteristic of a near symmetric rotor. A partial rotational analysis gives band origins and effective rotational constants for the first four vibrational levels of the ground state. The measured ground state vibrational constants are ω₀ = 1441.1 ± 1.0 cm^?1 with ω₀χ₀ = 10.9 ± 0.5 cm^?1. The substantial differences in the A–X emission spectra of HNF and its isoelectronic analog HOO are discussed as they relate to bonding trends in HAB molecules. The concepts presented are extended to other HAB systems.