Electronic relaxation processes of all-trans-2,4,6,8-decatetraene vapour revealed by the measurements of the S1 and S2 fluorescence |
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Authors: | Takao Itoh |
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Institution: | 1. Graduate School of Integrated Arts and Sciences , Hiroshima University , 1-7-1 Kagamiyama, Higashi-Hiroshima City, 739-8521 Japan titoh@hiroshima-u.ac.jp |
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Abstract: | Fluorescence and excitation spectra of all-trans-2,4,6,8-decatetraene vapour have been measured at different buffer gas pressures from 0 to 1.07 × 105 Pa (800 Torr). The quantum yield of the S1 fluorescence (ΦF(S1)) increases with increasing the buffer gas pressure, while that of the S2 fluorescence (ΦF(S2)) decreases slightly. ΦF(S1) decreases significantly with increasing the excitation energy under the collision free condition, while ΦF(S2) decreases only slightly. The pressure dependence of the fluorescence yields is interpreted in terms of the relaxation model involving the reversible internal conversion between S1 and S2 and the vibrational relaxation in the S1 manifold. The reverse S1 → S2 internal conversion rate is shown to be very slow compared with the forward S2 → S1 internal conversion rate. |
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Keywords: | decatetraene vapour excited states S2 fluorescence electronic relaxation |
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