ABSTRACT
Excited states of conjugated molecules such as aromatic hydrocarbons, dyes, and heteroaromatics are quenchable by a variety of small molecules. Of the many types of quenching processes that have been studied, the most extensive include energy and electron transfer processes [1-8]. Energy transfer quenching, especially singlet-singlet energy transfer can occur over both long and short ranges and is not restricted to collisional encounter or precomplexing between the donor and acceptor. In contrast, electron transfer quenching of excited states typically involves contact or near contact between the substrate and quencher and the rate falls off sharply with substrate-quencher separation [9-11]. Most
commonly, the effectiveness of a quenching process is assessed by the empirical Stem-Volmer (SV) Eq. (1),
where Io and I denote the fluorescence intensity in the absence and presence of quencher, respectively. Ksv is the quenching constant.
