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This paper reviews the new highly interdisciplinary research field studying the behavior of condensed matter systems exposed to radiation. The paper highlights several relevant examples of recent advances in the field and provides a roadmap for the development of the field in the next decade. Condensed matter systems exposed to radiation may have very different natures, being inorganic, organic or biological, finite or infinite, be composed of many different molecular species or materials, existing in different phases (solid, liquid, gaseous or plasma) and operating under different thermodynamic conditions. The essential and novel element of this research is that, despite the vast diversity of such systems, many of the key phenomena related to the behavior of irradiated systems (such as radiation-induced damage, mechanisms of damage repair and control, radiation protection, etc.) are very similar and can be understood based on the same fundamental theoretical principles and computational approaches. One of the essential features of the aforementioned phenomena concerns their multiscale nature as the manifestation of the radiation-induced effects occurring at different spatial and temporal scales ranging from the atomic to the macroscopic. The multiscale nature of the effects and similarity of their manifestation in systems of different origins necessarily brings together different disciplines, such as physics, chemistry, biology, materials and nano-science, and biomedical research, demonstrating numerous interlinks and commonalities between them. This research field is highly relevant to many novel and emerging technologies and medical applications., Comment: Roadmap paper; 376 pages, 32 figures. Submitted to Chemical Reviews

We use a novel technique to solvate silver cations in small clusters of noble gases. The technique involves formation of large, superfluid helium nanodroplets that are subsequently electron ionized, mass-selected by deflection in an electric field, and doped with silver atoms and noble gases (Ng) in pickup cells. Excess helium is then stripped from the doped nanodroplets by multiple collisions with helium gas at room temperature, producing cluster ions that contain no more than a few dozen noble gas atoms and just a few (or no) silver atoms. Under gentle stripping conditions helium atoms remain attached to the cluster ions, demonstrating their low vibrational temperature. Under harsher stripping conditions some of the heavier noble gas atoms will be evaporated as well, thus enriching stable clusters Ng$_n$Ag$_m^+$ at the expense of less stable ones. This results in local anomalies in the cluster ion abundance which is measured in a high-resolution time-of-flight mass spectrometer. Based on these data we identify specific "magic" sizes n of particularly stable ions. There is no evidence though for enhanced stability of Ng$_2$Ag$^+$, in contrast to the high stability of Ng$_2$Au$^+$ that derives from the covalent nature of the bond for heavy noble gases. "Magic" sizes are also identified for Ag$_2^+$ dimer ions complexed with He or Kr. Structural models will be tentatively proposed. A sequence of magic numbers $n$ = 12, 32, 44, indicative of three concentric solvation shells of icosahedral symmetry, is observed for He$_n$H$_2$O$^+$.