Luminescence Decay Times. Concentration Effects

Journal Article · Mon Jan 01 04:00:00 EST 1962 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.1733366· OSTI ID:4757866

Yguerabide, Juan; Burton, Milton

The optical properties (absorption spectrum, fluorescence spectrum, and luminescence decay) of solutions of 2,5diphenyloxazole (PPO) and p-terphenyl in benzene and cyclohexane are reported as functions of solute concentration. The absorption spectra of the solutions, when plotted as extinction coefficient vs wavelength, were unaffected by scintillator concentration, but the fluorescence spectrum of PPO solutions was affected in both intensity and shape. The luminescence decay of ail solutions studied was nonexponential and could be resolved into the sum of two exponential decays. The fluorescence spectra and decay curves were affected by oxygen. The interactions between excited and unexcited molecules and between unexcited molecules themselves and the effect which these interactions have on the optical properties of luminescent solutions were examined. The experimental results can be adequately explained by a mechanism which involves formation of transient dimers by an interaction between excited and unexcited molecules in addition to excitation of solute domains of unexcited solute molecules. It is shown that cage effects by themselves cannot account for the luminescent properties of the systems studied.

• Research Organization: Univ. of Notre Dame, Ind.
• Sponsoring Organization: USDOE
• NSA Number: NSA-17-004565
• OSTI ID: 4757866
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 8 Vol. 37; ISSN JCPSA6; ISSN 0021-9606
• Publisher: American Institute of Physics (AIP)
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ABSORPTION
BENZENE
CYCLOALKANES
EFFICIENCY
EXCITATION
FLUORESCENCE
HETEROCYCLICS
HEXANE
INTERACTIONS
LUMINESCENCE
MOLECULES
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
OXAZOLES
OXYGEN
PHENYL RADICALS
PHOSPHORS
POLYPHENYLS
SOLUTIONS
SPECTRA