title: Multiphoton-excited serotonin photochemistry.
abstract: We report photochemical and photophysical studies of a multiphoton-excited reaction of serotonin that previously has been shown to generate a photoproduct capable of emitting broadly in the visible spectral region. The current studies demonstrate that absorption of near-infrared light by an intermediate state prepared via three-photon absorption enhances the photoproduct formation yield, with the largest action cross sections ( approximately 10(-19) cm(2)) observed at the short-wavelength limit of the titanium:sapphire excitation source. The intermediate state is shown to persist for at least tens of nanoseconds and likely to be different from a previously reported oxygen-sensitive intermediate. In addition, the two-photon fluorescence action spectrum for the fluorescent photoproduct was determined and found to have a maximum at approximately 780 nm (3.2 eV). A general mechanism for this photochemical process is proposed.
authors.affiliation: Department of Chemistry and Biochemistry, The Institute for Cellular and Molecular Biology, and The Center for Nano and Molecular Science and Technology, The University of Texas, Austin, Texas 78712, USA.
authors.forename: Michael L
authors.initials: ML
authors.lastname: Gostkowski
authors.forename: Richard
authors.initials: R
authors.lastname: Allen
authors.forename: Matthew L
authors.initials: ML
authors.lastname: Plenert
authors.forename: Eric
authors.initials: E
authors.lastname: Okerberg
authors.forename: Mary Jane
authors.initials: MJ
authors.lastname: Gordon
authors.forename: Jason B
authors.initials: JB
authors.lastname: Shear
mesh_terms: D000537:Aluminum Oxide; D001703:Biophysics / Q000379:methods*; D007834:Lasers; D008027:Light; D008856:Microscopy, Fluorescence; D008956:Models, Chemical; D009991:Oscillometry; D010100:Oxygen / Q000378:metabolism; D010777:Photochemistry / Q000379:methods*; D017785:Photons; D011522:Protons; D012701:Serotonin / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013997:Time Factors; D014025:Titanium
chemical_list: D011522:Protons; D012701:Serotonin; D014025:Titanium; D000537:Aluminum Oxide; D010100:Oxygen