Excited-state absorption spectroscopy in oxidized Cytochrome c

This work reports on the excited-state absorption spectrum of oxidized Cytochrome c (Fe(3+)) dissolved in water, measured with the Z-scan technique with femtosecond laser pulses. The excited-state absorption cross-sections between 460 and 560 nm were determined with the aid of a three-energy-level model. Reverse saturable absorption was observed below 520 nm, while a saturable absorption process occurs in the Q-band, located around 530 nm. Above 560 nm, a competition between saturable absorption and two-photon absorption was inferred. These results show that Cytochrome c presents distinct nonlinear behaviors, which may be useful to study electron transfer chemistry in proteins by one- and two-photon absorption. In addition, owing to these nonlinear optical features, this molecule may be employed in applications involving photodynamics therapy and saturable absorbers. (C) 2009 Elsevier B.V. All rights reserved.

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

FAPESP (Fundacao de Amparo a Pesquisa do Estado de Sao Paulo)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

CNPq (Conselho Nacional de Desenvolvimento Cientifico e Tecnologico)

CAPES

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

U.S. Air Force Office of Scientific Research (AFOSR)

Air Force Office of Scientific Research (AFOSR) [FA9550-07-1-0374]