A spectroscopic study of the photodimerization of anthracene sandwich dimers in dianthracene

ISSN： 1362-3028

Source： Molecular Physics, Vol.27, Iss.2, 1974-02, pp. : 377-387

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Abstract

The photodimerization of anthracene sandwich pairs embedded in dianthracene single crystals has been studied by absorption and fluorescence spectroscopy over a wide range of temperature (6–295 K). An excimer state has been found to be the intermediate state in the formation of the dianthracene. The fluorescence efficiency of the sandwich pair is unity at very low temperature while the quantum yield for the dimerization process is unity at high temperatures. The thermal activation energy for the photodimerization process has been determined directly as well as from temperature dependence measurements of the fluorescence intensity. The two methods yield 590 ± 25 cm -1 and 611 ± 20 cm -1 respectively for this energy. Corresponding measurements were also carried out with the perdeuterated anthracene sandwich dimer. These show a marked deuterium effect.