Abstract
The objective of this study is to develop a quantitative measurement of temperature from fluoranthene fluorescence under conditions with elevated temperatures and pressures. Absorption and fluorescence of fluoranthene are studied in a pressure and temperature range of 0.1–4 MPa and 473–873 K for the two excitation wavelengths of 266 and 355 nm. The influence of thermodynamic parameters such as pressure, temperature and gas composition is characterized in a high-pressure and high-temperature facility. When increasing the pressure, the vibrational relaxation mechanisms are favored, which involves an increase of the fluorescence quantum yield. Concerning the temperature effect, the fluorescence decreases with increasing temperature, this is explained by efficient radiative mechanisms of intersystem crossing. The quenching effect is strongly efficient in air, with a fluorescence evolution described by the Stern–Volmer relation. Over the temperature range studied, the fluorescence quantum yield decreases exponentially by two orders of magnitude. From the temperature dependence of fluoranthene fluorescence in different ambient gases for 266 and 355 nm excitation, the potential temperature measurements in homogeneously and inhomogeneously seeded systems are suggested: the single-color detection technique, the single-excitation two-color detection technique and the dual-excitation wavelength technique.
Published Version
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