Photophysics of chlorin e6: from one- and two-photon absorption to fluorescence and phosphorescence

We present the study of optical and photophysical properties of chlorin e6, a known photosensitizer producing singlet oxygen. The linear and non-linear optical properties have been studied taking into account the dynamical and vibrational effects both by using Wigner distribution or coupling with molecular dynamics. A force field correctly describing the out-of-plane vibrations has been properly parameterized. The photophysical study revealed a possible efficient population of the triplet manifold, from the S-1 minimum region. Hence, fluorescence and singlet oxygen production are shown to coexist. Two-photon absorption high cross-section and far infrared absorption also suggest the possible use of chlorin e6 as an efficient sensitizer in two-photon absorption based phototherapy.