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Photochemical charge separation within aromatic hydrazines and the effect of exited-state intervalence in dihydrazines are studied. The results suggest that the most noticeable consequence of the exited-state intervalence is, under 60% as large for Hy2(super 14)NA compared to Hy(super 1)NA and for a significantly smaller Strokes shift for the distributed compared to the monosubstituted compounds Hy2(super 26)NA compared to Hy(super 2)NA.

A quantitative model of mixed-valence excited-state spectroscopy is developed and applied to 2,3-diphenyl-2,3-diazabicyclo[2.2.2]octane. The lowest-energy excited state of this molecule arises from a transition from the ground state, where the charge is located on the hydrazine bridge, to an excited state where the charge is associated with one phenyl group or the other. Coupling splits the absorption band into two components with the lower-energy component being the most intense. The sign of the coupling, derived by using a neighboring orbital model, is positive. The transition dipole moments consist of parallel and antiparallel vector components, and selection rules for each are derived. Bandwidths are caused by progressions in totally symmetric modes determined from resonance Raman spectroscopic analysis. The absorption, emission, and Raman spectra are fit simultaneously with one parameter set.