EUV photoionization of pure and doped He nanodroplets and Ne clusters

• Applicant: Professor Dr. Marcel Mudrich
• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas ; Experimental Condensed Matter Physics ; Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry
• Term: from 2015 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 269369328

• Final Report Year: 2020

Final Report Abstract

I proposed to conduct a series of experiments on direct and indirect photoionization of helium (He) nanodroplets and on neon (Ne) clusters using EUV radiation at the synchrotron Elettra in Trieste, Italy. The goal was to explore and systematically characterize various aspects of the photodynamics of pure and doped He droplets and Ne clusters initiated by resonant excitation or ionization. The special focus was on indirect ionization processes mediated by the transfer of charge and excitation due to electron correlations. Both pure and doped He nanodroplets were to be studied. Furthremore, the potential of He droplets of serving as a medium for EUV photoelectron spectroscopy of embedded molecules and complexes was to be assessed. The technique of coincidence velocity-map imaging of electrons and ions was to be employed. This project proceeded very successfully. 11 experimental campaigns were carried out, all of which produced valuable results, as summarized in 9 publications. Particular highlights were the first observation of single and double interatomic Coulombic decay (ICD) of pure and doped He nanodroplets, the first observation of electron transfer-mediated decay (ETMD) of doped He nanodroplets, and the first measurement of photoelectron spectra (PES) from dopants embedded in He nanodroplets. Thus, nearly all goals were reached.

Publications

• Enhanced Ionization of Embedded Clusters by Electron-Transfer-Mediated Decay in Helium Nanodroplets, Physical Review Letters 116, 203001 (2016)
  A. C. LaForge et al.
  (See online at https://doi.org/10.1103/PhysRevLett.116.203001)
• Fano resonances observed in helium nanodroplets, Physical Review A 93 050502(R) (2016)
  A. C. LaForge et al.
  (See online at https://doi.org/10.1103/PhysRevA.93.050502)
• Interatomic Coulombic decay in helium nanodroplets, Physical Review A 96, 013407 (2017)
  M. Shcherbinin et al.
  (See online at https://doi.org/10.1103/PhysRevA.96.013407)
• Penning Ionization of Acene Molecules by Helium Nanodroplets, The Journal of Physical Chemistry A 122, 1855–1860 (2018)
  M. Shcherbinin et al.
  (See online at https://doi.org/10.1021/acs.jpca.7b12506)
• Charge Exchange Dominates Long-Range Interatomic Coulombic Decay of Excited Metal-Doped Helium Nanodroplets, The Journal of Physical Chemistry Letters 10, 6904-6909 (2019)
  L. Ben Ltaief et al.
  (See online at https://doi.org/10.1021/acs.jpclett.9b02726)
• Highly efficient double ionization of mixed alkali dimers by intermolecular Coulombic decay, Nature Physics 15, 247 (2019)
  A. C. LaForge et al.
  (See online at https://doi.org/10.1038/s41567-018-0376-5)
• Inelastic scattering of photoelectrons from He nanodroplets, The Journal of Chemical Physics 150, 044304 (2019)
  M. Shcherbinin et al.
  (See online at https://doi.org/10.1063/1.5074130)
• Direct inner-shell photoionization of Xe atoms embedded in helium nanodroplets, Journal of Physics B: Atomic, Molecular and Optical Physics,
  L. Ben Ltaief et al.
  (See online at https://doi.org/10.1088/1361-6455/abaafb)
• Electron transfer mediated decay of alkali dimers attached to He nanodroplet, Physical Chemistry Chemical Physics 22, 8557-8564 (2020)
  L. Ben Ltaief et al.
  (See online at https://doi.org/10.1039/d0cp00256a)