Excited-state mixed valence in a diphenyl hydrazine cation: Spectroscopic consequences of coupling and transition dipole moment orientation.
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.
Lockard
Jenny V
JV
Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA.
Zink
Jeffrey I
JI
Trieber Ii
Dwight A
DA
Konradsson
Asgeir E
AE
Weaver
Michael N
MN
Nelsen
Stephen F
SF
D002412:Cations / Q000737:chemistry; D003198:Computer Simulation; D008956:Models, Chemical; D015394:Molecular Structure; D010659:Phenylhydrazines / Q000737:chemistry*; D013059:Spectrum Analysis, Raman
D002412:Cations; D010659:Phenylhydrazines; C032041:1,2-diphenylhydrazine