  Calculations are carried out to determine elastic scattering cross sections
and resonance energies for low energy electron impact on uracil and on each of
the DNA bases (thymine, cytosine, adenine, guanine), for isolated molecules in
their equilibrium geometry. Our calculations are compared with available theory
and experiment. We also attempt to correlate this information with experimental
dissociation patterns through an analysis of the temporary anion structures
that are formed by electron capture in shape resonances.
