92 research outputs found
Roadmap on dynamics of molecules and clusters in the gas phase
status: publishe
Roadmap on dynamics of molecules and clusters in the gas phase
This roadmap article highlights recent advances, challenges and future prospects in studies of the dynamics of molecules and clusters in the gas phase. It comprises nineteen contributions by scientists with leading expertise in complementary experimental and theoretical techniques to probe the dynamics on timescales spanning twenty order of magnitudes, from attoseconds to minutes and beyond, and for systems ranging in complexity from the smallest (diatomic) molecules to clusters and nanoparticles. Combining some of these techniques opens up new avenues to unravel hitherto unexplored reaction pathways and mechanisms, and to establish their significance in, e.g. radiotherapy and radiation damage on the nanoscale, astrophysics, astrochemistry and atmospheric science
Interaction of electrons with biologically relevant molecules
Recent years have witnessed an increase of the interest in the studies of the
interaction of electrons with biologically relevant molecules. This has been mainly
motivated by the seminal work, where it has been demonstrated that low energy
electrons can induce single and double strand breaks in DNA in the energy range
below the level of ionization. Since the damage profile as a function of electron
energy showed pronounced resonances it was proposed that resonant electron
capture could occur at particular molecular components of the DNA as the initial
step towards strand breaks. From a series of experiments on electron attachment
to DNA building blocks (nucleobases, the sugar moiety and the phosphate unit)
became obvious that they effectively capture electrons leading to the formation of
low energy resonances associated with the decomposition of the corresponding
molecule. Recent dissociative electron attachment experiments on an entire gas
phase nucleotide 2’-deoxycytidine-5´-monophosphate give also insight into the
molecular mechanism involved, which comprises both direct electron attachment
to the backbone and transfer of the excess electron from cytosine to the backbone
resulting in single strand breaks. The results further allow an estimate of the relative
contribution of these different mechanisms to single strand breaks
Unusual temperature dependence of the dissociative electron attachment cross section of 2-thiouracil
International audienceAt low energies (<3 eV), molecular dissociation is controlled by dissociative electron attachment for which the initial step, i.e., the formation of the transient negative ion, can be initiated by shape resonance or vibrational Feshbach resonance (VFR) mediated by the formation of a dipole bound anion. The temperature dependence for shape-resonances is well established; however, no experimental information is available yet on the second mechanism. Here, we show that the dissociation cross section for VFRs mediated by the formation of a dipole bound anion decreases as a function of a temperature. The change remains, however, relatively small in the temperature range of 370-440 K but it might be more pronounced at the extended temperature range
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