Effects of pressure and temperature on the fluorescence quantum yield of N-methylacridone in solution interpreted in terms of the eyring transition-state theory
- The influence of temperatur and pressure on the fluorescence quantum yield of N-methylacridone (9,10-dihydro-9-oxo-10-methyl-acridine) in toluene in the range of 283-313 K and 1 bar to 2.5 kbar, respectively, has been investigated. Treatment of the data in terms of the Eyring transition-state theory leads to a consistent interpretation of the observed effect. The unusually large increase of the quantum yield with increasing pressure is attributed to a positive volume of activation, ⊿V≠, for the thermally activated S1-T2 intersystem crossing which is known to be the only deactivation process (of the Si-state) competing with fluorescence. Comparison of the values for ⊿H≠, the activation enthalpy of this process, determined at various pressures, indicates a decrease in ⊿H≠ at elevated pressures. Since ⊿H≠ can be associated with the S1-T2 energy gap involved in intersystem crossing, this result further confirms the conclusion that the change in Franck-Condon factors alone cannot account for the decrease in the intersystem crossing rate with increasing pressure.
Author: | Hans-Dieter BrauerGND, Reinhard Schmidt, Bruno Hammerich |
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URN: | urn:nbn:de:hebis:30:3-742375 |
DOI: | https://doi.org/10.1515/zna-1981-0511 |
ISSN: | 1865-7109 |
Parent Title (German): | Zeitschrift für Naturforschung, A |
Publisher: | Verlag der Zeitschrift für Naturforschung |
Place of publication: | Tübingen |
Document Type: | Article |
Language: | English |
Date of Publication (online): | 2014/06/02 |
Year of first Publication: | 1981 |
Publishing Institution: | Universitätsbibliothek Johann Christian Senckenberg |
Release Date: | 2024/02/08 |
Volume: | 36.1981 |
Issue: | 5 |
Page Number: | 5 |
First Page: | 489 |
Last Page: | 493 |
Institutes: | Biochemie, Chemie und Pharmazie / Biochemie und Chemie |
Dewey Decimal Classification: | 5 Naturwissenschaften und Mathematik / 54 Chemie / 540 Chemie und zugeordnete Wissenschaften |
Sammlungen: | Universitätspublikationen |
Licence (German): | Creative Commons - Namensnennung-Nicht kommerziell-Keine Bearbeitung 3.0 |