Electron affinities and ionization potentials of nucleotide bases

Density-functional theory (B3LYP functional) is used to investigate the ion ization potentials and electron affinities of the DNA and RNA nucleotide ba ses. For the first time, anions lying lower in energy than the neutral spec ies have been calculated for both thymine and uracil (i.e., positive adiaba tic electron affinities). Additionally, the calculations show that anion fo rmation leads to significant geometrical changes to the nucleobases. This i s a very important finding as previous calculations have indicated that the anions are very similar in geometry to the neutral species and reported ne gative valence adiabatic electron affinities. (C) 2000 Elsevier Science B.V . All rights reserved.