Biophysical Chemistry

Temple University Department of Chemistry

Stark spectroscopy of DNA Photolyase

Stark spectroscopy allows us to measure the charge redistribution that occurs upon photoexcitation of the chromophore. The molecules’ permanent dipole moment causes a shift in energy in the presence of an externally applied electric field. This leads to a broadening of the absorption line and this can be analyzed to obtain the degree of charge displacement.

Expt.

Difference charge distribution for oxidized lumiflavin as determined from TD-DFT calculation

Experimental difference dipole moments derived from the Stark experiments, along with TD-DFT calculations of these quantities by the finite field method for oxidized lumiflavin