The tunability of synchrotron radiation and coincidence spectroscopic techniques enable a state- and sometime site-selective investigation of the energy deposition in relatively complex molecular species.
This approach has been used to investigate the fundamental mechanisms of VUV induced fragmentation of two different classes of radiosensitising molecules, i.e. the halopyrimidines  and the three isomers of nitroimidazole , used in radiotherapy to selectively enhance radiation damage on tumor rather than healthy cells.
In the case of the halopyrimidines the role of the halogen atom and its position have been studied. A clear state-selectivity in the molecular fragmentation has been observed and it has related to the peculiar charge distribution of the individual molecular orbitals.
In the case of the three isomers of nitroimidazole the radiation-induced decomposition displays different features depending on the isomer. The combination of the experimental results and DFT calculations, which fully explain the observed differences between the isomers, reveals the subtle and peculiar fragmentation mechanisms that may play a fundamental role in the specific radiosensitisation during radiotherapy.
In a third example it is shown how state-selected photofragmentation spectra can be used to estimate the distribution of the energy transfer in ion induced fragmentation . The method has been tested on thymdine.
Acklowledgement. This work was partially supported by the Serbia–Italy Joint Research Project PGR220 ‘A nanoview of radiation-biomatter interaction’ and the XLIC COST Action CM1204 via the STSM program.
 M.C. Castrovilli et al. 2014J. Am. Soc. Mass Spectrom. 25, 351-367.
 P. Bolognesi et al. 2016J.Chem.Phys. Comm. 145, 191102.
 S. Maclot et al. 2016 Phys.Rev.Lett. 117, 073201