Thermal energy assisted heavy atom effect: fluorescence quenching of 9-cyanoanthracene in the supercritical fluid of Xe
✍ Scribed by Makoto Maeda; Urs Graf; Hiromichi Niikura; Masami Okamoto; Satoshi Hirayama
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 443 KB
- Volume
- 257
- Category
- Article
- ISSN
- 0009-2614
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✦ Synopsis
The fluorescence lifetime, rf, of 9-cyanoanthracene (9CNA) in the supercritical fluid (SF) of Xe (6.8 MPa at 293 K) is found to be 2.39 _ 0.13 ns, which is much shorter than the 17.78 _+ 0.43 ns measured in SF of CO 2. This large decrease in Tf is interpreted in terms of the vibronic-level-dependent heavy atom effect which is revealed by a comparison of the absorption and fluorescence excitation spectra measured for the 1:1 van der Waals complex of 9CNA with Xe generated in a supersonic jet. The effect of the temperature on Tf observed in Xe is concordant with the vibronic-level-dependent heavy atom effect.