UV exposure of DNA is known to trigger off photochemical reactions that ultimately may lead to carcinogenic mutations. However, the primary UV-induced processes in DNA preceding such reactivity remain unclear even after several decades of intense studies. With this in mind, we have recently undertaken a program aiming at improving the understanding of DNA photodamage. The ultimate goal is to develop a model for the excited state dynamical processes, and in particular the role of energy transfer, occurring within the DNA molecule after the initial energy deposition. Evidently, the success of this project relies on a precise knowledge of the photophysical properties of the excited states of its monomeric constituents (nucleobases, nucleosides, nucleotides) and how these properties translate into those of the organised system of DNA.
