The Origin of the Wavelength-Dependent Photoreactivity of
trans-Urocanic Acid
Kerry M. Hanson & John D. Simon
Two-color, pulsed-laser photoacoustic calorimetry is used to distinguish between
multiple rotamer or electronic state contributions to the absorption spectrum
of the epidermal chromophore trans-urocanic acid. The data definitively show
that the wavelength-dependent photochemistry of trans-urocanic acid results
from the presence of two distinct, weakly coupled electronic states absorbing
between 264 nm and 310 nm.
Photochemistry and Photobiology 67, 538 (1998)