Excited singlet‐state lifetimes of hydrated chlorophyll aggregates

Autor:	A. J. Alfano, M. S. Showell, F. E. Lytle, Francis K. Fong
Rok vydání:	1985
Předmět:	Annihilation Quenching (fluorescence) Chemistry Exciton food and beverages General Physics and Astronomy macromolecular substances Fluorescence Photon counting Intersystem crossing Excited state polycyclic compounds Radiative transfer Physical and Theoretical Chemistry Atomic physics
Zdroj:	The Journal of Chemical Physics. 82:758-764
ISSN:	1089-7690 0021-9606
DOI:	10.1063/1.448500
Popis:	A time‐correlated single photon counting technique, coupled with a red sensitive photomultiplier tube, was used to determine the singlet‐state lifetimes and energy transfer mechanisms of Chl a⋅H2O, (Chl a⋅H2O)2, and (Chl a⋅2H2O)n. The use of low concentrations and low incident light fluxes permitted measurements in a regime where nonlinear quenching effects are absent. The lifetimes exhibit a pronounced dependence on aggregate size. The results are examined in terms of exciton interactions in the excited singlet state of the Chl a aggregate. It is shown that in the absence of exciton annihilation effects, the rate of singlet‐state decay via radiative coupling and intersystem crossing of a Chl a aggregate containing n equivalent monomeric units is equal to n times that of monomeric Chl a.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::8240e169c80692d73aaacd0fe9a4d32d https://doi.org/10.1063/1.448500 Zobrazit plný text záznamu