Resonant interactions of slow electrons with DNA constituents

We review recent theoretical work on low-energy electron collisions with the constituents of DNA and RNA, including the nucleobases (uracil, thymine, cytosine, adenine, and guanine), deoxyribose and its analogue tetrahydrofuran, and larger subunits including deoxynucleosides and deoxynucleotides. A particular focus is on the identification and characterization of low-energy resonances that may play a role in electron attachment leading to DNA strand breaking. Comparison with experiment indicates that high-level calculations can yield rather accurate resonance positions. However, the higher-lying π*π* resonances of the nucleobases appear to be of mixed elastic and core-excited character. This mixing must be accounted for in the calculation to obtain reliable resonance energies and may affect the electron-induced dissociation mechanisms. Resonant channel mixing is illustrated for the pyrimidine base analogue pyrazine.