| 1. |
- Hans, Andreas, et al.
(författare)
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Optical Fluorescence Detected from X-ray Irradiated Liquid Water
- 2017
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Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 121:10, s. 2326-2330
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Tidskriftsartikel (refereegranskat)abstract
- Despite its importance, the structure and dynamics of liquid water are still poorly understood in many apsects. Here, we report on the observation of optical fluorescence upon soft X-ray irradiation of liquid water. Detection of spectrally resolved fluorescence was achieved by a combination of the liquid microjet technique and fluorescence spectroscopy. We observe a genuine liquid-phase fluorescence manifested by a broad emission band in the 170-340 nm (4-7 eV) photon wavelength range. In addition, another narrower emission near 300 nm can be assigned to the fluorescence of OH (A state) in the gas phase, the emitting species being formed by Auger electrons escaping from liquid water. We argue that the newly observed broad-band emission of liquid water is relevant in search of extraterrestrial life, and we also envision the observed electron-ejection mechanism to find application for exploring solutes at liquid vapor interfaces.
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| 2. |
- Hans, Andreas, et al.
(författare)
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Soft X-ray induced ultraviolet fluorescence emission from bulk and interface of a liquid water microjet
- 2017
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Ingår i: Journal of Physics, Conference Series. - : Institute of Physics Publishing (IOPP). - 1742-6588 .- 1742-6596. ; 875
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Tidskriftsartikel (refereegranskat)abstract
- Tremendous progress has been made in the research on the structure and dynamics of liquids due to the development of advanced experimental techniques such as liquid microjets, enabling investigations on volatile samples in ultrahigh vacuum environments. The spectroscopy of charged particles, e.g. photoelectron or Auger electron spectroscopy on liquids, is an established field by now. Here, we report on the successful application of a fluorescence spectrometer to measure optical emission spectra from liquids irradiated with soft X-ray synchrotron radiation.
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| 3. |
- Hans, Andreas, et al.
(författare)
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Suppression of X-ray-Induced Radiation Damage to Biomolecules in Aqueous Environments by Immediate Intermolecular Decay of Inner-Shell Vacancies
- 2021
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Ingår i: Journal of Physical Chemistry Letters. - : American Chemical Society (ACS). - 1948-7185 .- 1948-7185. ; 12:30, s. 7146-7150
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Tidskriftsartikel (refereegranskat)abstract
- The predominant reason for the damaging power of high-energy radiation is multiple ionization of a molecule, either direct or via the decay of highly excited intermediates, as, e.g., in the case of X-ray irradiation. Consequently, the molecule is irreparably damaged by the subsequent fragmentation in a Coulomb explosion. In an aqueous environment, however, it has been observed that irradiated molecules may be saved from fragmentation presumably by charge and energy dissipation mechanisms. Here, we show that the protective effect of the environment sets in even earlier than hitherto expected, namely immediately after single inner-shell ionization. By combining coincidence measurements of the fragmentation of X-ray-irradiated microsolvated pyrimidine molecules with theoretical calculations, we identify direct intermolecular electronic decay as the protective mechanism, outrunning the usually dominant Auger decay. Our results demonstrate that such processes play a key role in charge delocalization and have to be considered in investigations and models on high-energy radiation damage in realistic environments.
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