Campus Units

Chemistry

Document Type

Article

Publication Version

Published Version

Publication Date

9-16-1999

Journal or Book Title

The Journal of Physical Chemistry A

Volume

103

Issue

40

First Page

7949

Last Page

7957

DOI

10.1021/jp992436a

Abstract

The excited-state intramolecular H atom transfer reaction occurring in hypericin and hypocrellin A is investigated by means of the fluorescence upconversion technique in a variety of solvents. Rising components of ∼10 ps, attributable to intramolecular H atom transfer, are clearly observed in the fluorescence upconversion traces of both hypericin and hypocrellin A. The amplitude of the rising component is emission wavelength dependent and occurs on the blue edge of the emission spectra. Neither in hypericin nor in hypocrellin A does this fluorescent component exhibit a deuterium isotope effect. This result identifies it with the ∼10 ps component, also lacking a deuterium isotope effect, observed in hypericin in transient absorption measurements monitoring stimulated emission. The clear and complementary observation in fluorescence of the ∼10 ps component in both hypericin and hypocrellin A is a crucial link in refining a unified model of the hypericin and hypocrellin photophysics that we first proposed in J. Phys. Chem. B 1998, 102, 6098.

Comments

Reprinted (adapted) with permission from The Journal of Physical Chemistry A, 103(40); 7949-7957. doi: 10.1021/jp992436a. Copyright 1999 American Chemical Society.

Copyright Owner

American Chemical Society

Language

en

File Format

application/pdf

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