FLUORESCENCE OF SINGLE ANTHRACENE CRYSTALS AT LOW TEMPERATURES
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Date
1957
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Publisher
Ohio State University
Abstract
“A low temperature cell of the type described by Duerig and $Mador^{1}$ was used to study the polarized fluorescence from anthracene sublimation flakes at $77^\circ$ and $4^\circ K$. A recording spectrometer was used to measure accurately the relative intensity of the two crystal polarizations (parallel to the $b$ and $a$ axis respectively) and also to determine differences in the fluorescence spectrum between $77^\circ$ and $4^\circ K$. The polarization ratio ($b/a$) was found to decrease through the spectrum in an unusual manner and measurements taken at $77^\circ$ and $4^\circ K$ indicate that there is more than one emitting level and that these have different polarization properties. The fluorescence, as is well known, arises from regions of weak absorption in the crystal and the interpretation of these levels will be discussed. The polarized fluorescence excited from anthracene crystals containing traces of tetracene will be reported. It was found that the transfer efficiency can either increase or decrease in going from $77^\circ$ to $4^\circ K$ depending on a random selection of crystal samples, and here again the results can be interpreted in terms of more than one emitting level for the anthracene fluorescence. The depolarization of the tetracene fluorescence at low temperatures reported by $Sidman^{2}$ was not found. In addition, the polarized absorption spectrum of each crystal was determined, but these will not be reported except where relevant to the fluorescence spectra.”
Description
$^{2}$J. W. Sidman, J. Chem. Phys. 25, 122 (1956). $^{1}$W. H. Duerig and I. L. Mador, Rev. Sci. Instr. 23. 421 (1952).
Author Institution: Division of Pure Chemistry, National Research Council
Author Institution: Division of Pure Chemistry, National Research Council