The Moran Group

Light driven electron and energy transfer
processes abound in nature and technology.
Our research specializes to systems in
which these dynamics occur on the
femtosecond time scale. The general goal of
our experimental work is to understand
how interactions between electrons and
nuclei control the outcome of photoinduced
events. Of particular interest are
connections between molecular relaxation
processes in condensed phases and
characteristics of the “noise” present in
such fluctuating environments. Recent
studies have been directed at photoinduced
relaxation processes in DNA bases,
photosynthetic complexes, and organic
semiconductors. Our experimental work is
complemented by theory and numerical
simulations.

Nonlinear laser spectroscopies are the
common tool used in our research projects.
These experiments effectively synchronize
photoinduced events in a large population of
individual molecules then track relaxation
with femtosecond time resolution. We are
particularly interested in developing novel
multi- dimensional spectroscopies that
correlate electronic motion to nuclear
structure in systems composed of
interacting chromophores. The
development of equipment used to generate
laser pulses with widely tunable
frequencies and bandwidths is important
for meeting our research objectives.

Nonlinear optical signatures of strong
molecule-TiO2 interactions have been
established using model systems spanning the
weak and strong coupling regimes. We find that
the amplitudes of photoinduced vibrational
coherences are positively correlated with the
delocalization of molecular orbitals between
species at the interface.[44]