  On the basis of first-principles GW calculations, we study the quasiparticle
properties of the guanine, adenine, cytosine, thymine, and uracil DNA and RNA
nucleobases. Beyond standard G0W0 calculations, starting from Kohn-Sham
eigenstates obtained with (semi)local functionals, a simple self-consistency on
the eigenvalues allows to obtain vertical ionization energies and electron
affinities within an average 0.11 eV and 0.18 eV error respectively as compared
to state-of-the-art coupled-cluster and multi-configurational perturbative
quantum chemistry approaches. Further, GW calculations predict the correct \pi
-character of the highest occupied state, thanks to several level crossings
between density functional and GW calculations. Our study is based on a recent
gaussian-basis implementation of GW with explicit treatment of dynamical
screening through contour deformation techniques.
