Low energy electrons (LEE) below 4 eV have beenexperimentally found to result in single- strand breaks formation in DNA. Theexploration of underlying mechanism of strand breaks formation is of immenseinterest from theory and experimental points of view. The interaction of lowenergy electrons with DNA produces transient negative ions (TNI) which can beunderstood as interactions of the electron with unoccupied molecular orbitalsof neutral molecule and can be treated with theoretical methods such as timedependent-density functional theory (TD-DFT). With this concept, we calculatedthe excited states of number of DNA model system  radical anions as TNI or adiabatic ion statesusing  TD-DFT.  The calculated excited states show that below2 eV the presence of dissociative s* state is responsible for facile strandbreaks formation in agreement with the experiment. However, in with solvationthese s* states are found to be blue shifted by several eVs.

Anion radical excited states from low energy electron addition:  DNA strand break formation

240th National Meeting (2010)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.