The role of the shape resonance state in low energy electron induced single strand break in 2'-deoxycytidine-5'-monophosphate.

Abstract

Low energy electron (LEE) induced single strand break (SSB) has been studied for 2'-deoxycytidine-5'-monophosphate (5'-dCMPH) molecules in the gas phase by means of ab initio electronic structure methods and local complex potential based time-dependent wavepacket quantum mechanical calculations. We have found that the LEE attachment to this cytidine nucleotide results in the formation of a transient metastable anion. The results obtained here show that the electron attachment takes place at the cytosine nucleobase center and within 18-20 fs, the LEE transfers to the σ* orbital of the sugar-phosphate 5' C-O bond. The characteristic electron attachment cross section spectrum is found at ∼1 eV, which is in good agreement with the available experimental observations. Quantum mechanical tunneling of the 5' C-O bound vibrational energy levels may contribute to SSB only above 1.5 eV energy regimes.