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Electronic relaxation processes in polyatomic molecules. Progress report, October 1, 1975--September 30, 1976

Technical Report ·
DOI:https://doi.org/10.2172/7248141· OSTI ID:7248141
Excitation energy dependence of radiationless decay rate under collision-free conditions was utilized as a probe of intramolecular vibrational relaxation in tetracene and pentacene. The results give evidence of vibrational relaxation which competes with electronic relaxation. The substitution dependence of T/sub 1/(n..pi..*) ..-->.. S/sub 0/ radiationless transition in monocyclic diazines and the temperature dependence of S/sub 1/ non-radiative decay rate in alcoholic solutions of polycyclic monoazines indicate that the vibronic interaction between the lowest energy n..pi..* and ..pi pi..* states leads to a rapid radiationless deactivation of the lower of the two electronic states. Finally, a photon-counting spectrofluorometer of very high sensitivity was constructed, and it was used to record T/sub 2/ ..-->.. T/sub 1/ fluorescence in bromoanthracenes and S/sub 2/ ..-->.. S/sub 1/ fluorescence in azulene. These spectra represent the first bona-fide, or the most convincing, observation of fluorescence between excited electronic states.
Research Organization:
Wayne State Univ., Detroit, Mich. (USA)
Sponsoring Organization:
US Energy Research and Development Administration (ERDA)
OSTI ID:
7248141
Report Number(s):
COO-2192-22
Country of Publication:
United States
Language:
English

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Related Subjects

640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
AROMATICS
AZINES
AZULENE
BROMINATED AROMATIC HYDROCARBONS
CONDENSED AROMATICS
DECAY
ENERGY DEPENDENCE
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITATION
EXCITED STATES
FLUORESCENCE
HALOGENATED AROMATIC HYDROCARBONS
HETEROCYCLIC COMPOUNDS
HYDROCARBONS
LUMINESCENCE
ORGANIC BROMINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
RELAXATION
VIBRATIONAL STATES