Quantum yield irreversible quenching

C = compound T = tautomer a) tautomer 1 with shortwave Sq-Si transition tautomer 2 with longwave Sq-Si transition b) values of fluorescence quantum yield were measured for tautomers 1, which were the predominating component in solution at 77 K c) fluorescence of compound 1 is strongly quenched in dimer at 77 K due to the irreversible energy transfer to compound 2. 

Despite uncertainty related to irreversible electrochemistry, the trend for the re-ducibility of the nucleobases was established as T,U C A > G [26], Because of this trend, we expect that the U radical anion should only be able to reduce adjacent pyrimidine bases. In accordance with this assumption we expect different emission quantum yield, depending on the nature of the adjacent DNA bases (Figure 4.6.11). In fact, duplex PI has a high emission quantum yield, because ET from the Py-dU group to the adjacent A is not expected. In contrast, significant quenching of the emission can be observed when a T or C is placed adjacent to the... 

The photoluminescence (PL) quantum yield of CdSe/ZnS core-shell quantum dots (QDs) strongly depends on ionic nature of molecules used as solubilizing agents and as molecular templates for further nanoengineering. Quantum yield of PL for initially bright cationic-capped QDs irreversibly decreases to zero. On the contrary, PL and photostability of partially quenched anionic-capped QDs are strongly enhanced upon interaction with cationic polyelectrolyte, which may be more preferable template for this reason. 

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