Photophysical characterization of a photochromic system: The case of merocyanine 540

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The fluorescence emission of merocyanine 540 (MC540) in 95% ethanol was studied under continuous irradiation. Fluorescence spectra from excited states of both normal (N) and photoisomeric (P) species are identical. The laser fluence dependence of the fluorescence intensity is interpreted on the basi...

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Autores principales:	Aramendía, P.F., Duchowicz, R., Scaffardi, L., Tocho, J.O.
Formato:	Artículo publishedVersion
Publicado:	1990
Acceso en línea:	http://hdl.handle.net/20.500.12110/paper_00223654_v94_n4_p1389_Aramendia https://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_00223654_v94_n4_p1389_Aramendia_oai
Aporte de:	Repositorio Digital de la Universidad de Buenos Aires (UBA) de Universidad de Buenos Aires

id	I28-R145-paper_00223654_v94_n4_p1389_Aramendia_oai
record_format	dspace
spelling	I28-R145-paper_00223654_v94_n4_p1389_Aramendia_oai2024-08-16 Aramendía, P.F. Duchowicz, R. Scaffardi, L. Tocho, J.O. 1990 The fluorescence emission of merocyanine 540 (MC540) in 95% ethanol was studied under continuous irradiation. Fluorescence spectra from excited states of both normal (N) and photoisomeric (P) species are identical. The laser fluence dependence of the fluorescence intensity is interpreted on the basis of a photochromic system involving N and P ground states and first excited singlet states. Common flash photolysis equations are generalized in order to include a photoequilibrium between isomers. The emission data are used together with previous flash photolysis and optoacoustic results to obtain P fluorescence and photoisomerization quantum yields as 0.07 ± 0.02 and 0.20 ± 0.04, respectively, P absorption cross section at the maximum (560 nm) as 4.74 × 10-16 cm2 (125 × 103 M-1·cm-1), and the energy difference between the ground states as 165 kJ·mol-1. Internal conversion, which can take place as a direct process or through a twisted state, is the main deactivation pathway for excited singlet P. © 1990 American Chemical Society. Fil:Aramendía, P.F. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. application/pdf http://hdl.handle.net/20.500.12110/paper_00223654_v94_n4_p1389_Aramendia info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar Journal of Physical Chemistry 1990;94(4):1389-1392 Photophysical characterization of a photochromic system: The case of merocyanine 540 info:eu-repo/semantics/article info:ar-repo/semantics/artículo info:eu-repo/semantics/publishedVersion https://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_00223654_v94_n4_p1389_Aramendia_oai
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-145
collection	Repositorio Digital de la Universidad de Buenos Aires (UBA)
description	The fluorescence emission of merocyanine 540 (MC540) in 95% ethanol was studied under continuous irradiation. Fluorescence spectra from excited states of both normal (N) and photoisomeric (P) species are identical. The laser fluence dependence of the fluorescence intensity is interpreted on the basis of a photochromic system involving N and P ground states and first excited singlet states. Common flash photolysis equations are generalized in order to include a photoequilibrium between isomers. The emission data are used together with previous flash photolysis and optoacoustic results to obtain P fluorescence and photoisomerization quantum yields as 0.07 ± 0.02 and 0.20 ± 0.04, respectively, P absorption cross section at the maximum (560 nm) as 4.74 × 10-16 cm2 (125 × 103 M-1·cm-1), and the energy difference between the ground states as 165 kJ·mol-1. Internal conversion, which can take place as a direct process or through a twisted state, is the main deactivation pathway for excited singlet P. © 1990 American Chemical Society.
format	Artículo Artículo publishedVersion
author	Aramendía, P.F. Duchowicz, R. Scaffardi, L. Tocho, J.O.
spellingShingle	Aramendía, P.F. Duchowicz, R. Scaffardi, L. Tocho, J.O. Photophysical characterization of a photochromic system: The case of merocyanine 540
author_facet	Aramendía, P.F. Duchowicz, R. Scaffardi, L. Tocho, J.O.
author_sort	Aramendía, P.F.
title	Photophysical characterization of a photochromic system: The case of merocyanine 540
title_short	Photophysical characterization of a photochromic system: The case of merocyanine 540
title_full	Photophysical characterization of a photochromic system: The case of merocyanine 540
title_fullStr	Photophysical characterization of a photochromic system: The case of merocyanine 540
title_full_unstemmed	Photophysical characterization of a photochromic system: The case of merocyanine 540
title_sort	photophysical characterization of a photochromic system: the case of merocyanine 540
publishDate	1990
url	http://hdl.handle.net/20.500.12110/paper_00223654_v94_n4_p1389_Aramendia https://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_00223654_v94_n4_p1389_Aramendia_oai
work_keys_str_mv	AT aramendiapf photophysicalcharacterizationofaphotochromicsystemthecaseofmerocyanine540 AT duchowiczr photophysicalcharacterizationofaphotochromicsystemthecaseofmerocyanine540 AT scaffardil photophysicalcharacterizationofaphotochromicsystemthecaseofmerocyanine540 AT tochojo photophysicalcharacterizationofaphotochromicsystemthecaseofmerocyanine540
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Photophysical characterization of a photochromic system: The case of merocyanine 540

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