Oxidative damage to DNA as well as hole transport between nucleobases in oxidized DNA are
important processes in lesion formation for which surprisingly poor thermodynamic data exists; the
relative ease of oxidizing the four nucleobases being one such example. Theoretical simulations of
radiation damage and charge transport in DNA depend on accurate values for vertical ionization energies
(VIEs) and reorganization energies as well as standard reduction potentials. Liquid-jet photoelectron
spectroscopy can be used to directly study the oxidation half-reaction. The VIEs of nucleic acid building
blocks are measured in their native buffered aqueous environment. The experimental investigation of
purine and pyrimidine nucleotides, nucleosides, pentose sugars, and inorganic phosphate demonstrate that
photoelectron spectra of nucleotides arise as a spectral sum over their individual chemical components,
that is to say that electronic interactions between each component are effectively screened from one
another by water. Electronic structure theory affords the assignment of the lowest energy photoelectron
band in all investigated nucleosides and nucleotides to a single ionizing transition centered solely on the
nucleobase. Thus combining the measured VIEs with theoretically determined reorganization energies
allows for the spectroscopic determination of the one-electron redox potentials that have been difficult to
establish via electrochemistry.