INVESTIGADORES
SCAFFARDI Lucia Beatriz
artículos
Título:
STUDY OF PHOTOISOMERIZATION DYNAMICS OF THE DTDCI CYANINE DYE
Autor/es:
P. VAVELIUK; L. SCAFFARDI ; R. DUCHOWICZ
Revista:
OPTICAL ENGINEERING
Editorial:
SPIE-SOC PHOTOPTICAL INSTRUMENTATION ENGINEERS
Referencias:
Año: 1996 p. 98 - 103
ISSN:
0091-3286
Resumen:
Simultaneous laser absorption spectroscopy and laser induced fluorescence under steady-state conditions,together with analysis of fluorescence spectra at various excitation conditions, have been carried out to elucidatethe photoisomerization processes of 3,3¢-diethylthiadicarbocyanine iodide (DTDCI) in methanol solution. Thedata were obtained by varying the laser fluence at several wavelengths, and fits were performed consideringtwo kinetic models, involving two or three isomers. The results point to the formation of a second photoisomerunder high excitation fluences. Its absorption spectrum is shifted toward longer wavelengths with respect tothe spectra corresponding to the normal species and the first photoisomer, which are strongly overlapped.Changes in the fluorescence spectra with the excitation fluence, appearing in the DTDCI lasing region, areattributed to the second photoisomer emission. Values are obtained for the photoisomerization and backphotoisomerizationquantum yields, as well as for the thermal ground-state back-isomerization yield and groundstate absorption cross sections at several wavelengths for both photoisomers.