Article | Published:

Observation of electron-transfer-mediated decay in aqueous solution

Nature Chemistry volume 9, pages 708714 (2017) | Download Citation

Abstract

Photoionization is at the heart of X-ray photoelectron spectroscopy (XPS), which gives access to important information on a sample's local chemical environment. Local and non-local electronic decay after photoionization—in which the refilling of core holes results in electron emission from either the initially ionized species or a neighbour, respectively—have been well studied. However, electron-transfer-mediated decay (ETMD), which involves the refilling of a core hole by an electron from a neighbouring species, has not yet been observed in condensed phase. Here we report the experimental observation of ETMD in an aqueous LiCl solution by detecting characteristic secondary low-energy electrons using liquid-microjet soft XPS. Experimental results are interpreted using molecular dynamics and high-level ab initio calculations. We show that both solvent molecules and counterions participate in the ETMD processes, and different ion associations have distinctive spectral fingerprints. Furthermore, ETMD spectra are sensitive to coordination numbers, ion–solvent distances and solvent arrangement.

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References

  1. 1.

    Auger processes in the 21st century. Int. J. Radiat. Biol. 84, 959–975 (2008).

  2. 2.

    et al. X-ray photolysis to release ligands from caged reagents by an intramolecular antenna sensitive to magnetic resonance imaging. Angew. Chem. Int. Ed. 50, 9708–9711 (2011).

  3. 3.

    , & Giant intermolecular decay and fragmentation of clusters. Phys. Rev. Lett. 79, 4778–4781 (1997).

  4. 4.

    et al. Interatomic electronic decay processes in singly and multiply ionized clusters. J. Electron Spectrosc. Relat. Phenom. 183, 36–47 (2011).

  5. 5.

    Production of low kinetic energy electrons and energetic ion pairs by intermolecular Coulombic decay. Int. J. Radiat. Biol. 88, 871–883 (2012).

  6. 6.

    , , , & Interaction between liquid water and hydroxide revealed by core-hole de-excitation. Nature 455, 89–91 (2008).

  7. 7.

    et al. Ionic-charge dependence of the intermolecular Coulombic decay time scale for aqueous ions probed by the core-hole clock. J. Am. Chem. Soc. 133, 13430–13436 (2011).

  8. 8.

    , , & Proton-transfer mediated enhancement of nonlocal electronic relaxation processes in X-ray irradiated liquid water. J. Am. Chem. Soc. 136, 18170–18176 (2014).

  9. 9.

    et al. Ultrafast energy transfer between water molecules. Nat. Phys. 6, 139–142 (2010).

  10. 10.

    et al. A hitherto unrecognized source of low-energy electrons in water. Nat. Phys. 6, 143–146 (2010).

  11. 11.

    , & Electronic decay in weakly bound heteroclusters: energy transfer versus electron transfer. J. Chem. Phys. 115, 5076–5088 (2001).

  12. 12.

    , , & Enhanced one-photon double ionization of atoms and molecules in an environment of different species. Phys. Rev. Lett. 112, 193001 (2014).

  13. 13.

    et al. Enhanced ionization of embedded clusters by electron-transfer-mediated decay in helium nanodroplets. Phys. Rev. Lett. 116, 203001 (2016).

  14. 14.

    , , , & Autoionization mediated by electron transfer. Phys. Rev. Lett. 106, 33402 (2011).

  15. 15.

    et al. Electron-transfer-mediated decay and interatomic Coulombic decay from the triply ionized states in argon dimers. Phys. Rev. Lett. 106, 33401 (2011).

  16. 16.

    et al. Observation of interatomic Coulombic decay and electron-transfer- mediated decay in high-energy electron-impact ionization of Ar2. Phys. Rev. A 88, 42712 (2013).

  17. 17.

    , & Possible electronic decay channels in the ionization spectra of small clusters composed of Ar and Kr: a four-component relativistic treatment. J. Chem. Phys. 129, 24304 (2008).

  18. 18.

    , , & Efficient pathway to neutralization of multiply charged ions produced in Auger processes. Phys. Rev. Lett. 110, 258302 (2013).

  19. 19.

    & Electronic decay following ionization of aqueous Li+ microsolvation clusters. J. Chem. Phys. 122, 94305 (2005).

  20. 20.

    , & The role of metal ions in X-ray-induced photochemistry. Nat. Chem. 8, 237–241 (2016).

  21. 21.

    et al. Photoemission from aqueous alkali-metal-iodide salt solutions using EUV synchrotron radiation. J. Phys. Chem. B 108, 4729–4736 (2004).

  22. 22.

    & Concentration effects on aqueous lithium chloride solutions. Molecular dynamics simulations and X-ray scattering studies. J. Mol. Liq. 197, 77–83 (2014).

  23. 23.

    , , & Ab initio molecular dynamics study of a highly concentrated LiCl aqueous solution. J. Chem. Theory Comput. 4, 1040–1048 (2008).

  24. 24.

    & Hydration structure in concentrated aqueous lithium chloride solutions: a reverse Monte Carlo based combination of molecular dynamics simulations and diffraction data. J. Chem. Phys. 137, 204503 (2012).

  25. 25.

    , , & Hydration of the chloride ion in concentrated aqueous solutions using neutron scattering and molecular dynamics. Mol. Phys. 112, 1230–1240 (2014).

  26. 26.

    , & Ion pairing in aqueous lithium salt solutions with monovalent and divalent counter-anions. J. Phys. Chem. A 117, 11766–11773 (2013).

  27. 27.

    , , & Computer simulation study of the structure of LiCl aqueous solutions: test of non-standard mixing rules in the ion interaction. J. Phys. Chem. B 118, 7680–7691 (2014).

  28. 28.

    , , & Ionic solvation and association in LiCl aqueous solution: a density functional theory, polarised continuum model and molecular dynamics investigation. Mol. Phys. 112, 1710–1723 (2014).

  29. 29.

    et al.. Charge dependence of solvent-mediated intermolecular Coster−Kronig decay dynamics of aqueous ions. J. Phys. Chem. B 114, 17057–17061 (2010).

  30. 30.

    . When spectroscopy fails: the measurement of ion pairing. Pure Appl. Chem. 78, 1571–1586 (2006).

  31. 31.

    et al. Water-mediated ion pairing: occurrence and relevance. Chem. Rev. 116, 7626–7641 (2016).

  32. 32.

    et al. Direct evidence of orbital mixing between water and solvated transition-metal ions: an oxygen 1s XAS and DFT study of aqueous systems. J. Phys. Chem. A 107, 6869–6876 (2003).

  33. 33.

    et al. The anion effect on Li+ ion coordination structure in ethylene carbonate solutions. J. Phys. Chem. Lett. 7, 3554–3559 (2016).

  34. 34.

    , & Photoelectron spectroscopy meets aqueous solution: studies from a vacuum liquid microjet. J. Phys. Chem. Lett. 2, 633–641 (2011).

  35. 35.

    , & The missing term in effective pair potentials. J. Phys. Chem. 91, 6269–6271 (1987).

  36. 36.

    & Accounting for electronic polarization in non- polarizable force fields. Phys. Chem. Chem. Phys. 13, 2613–2626 (2011).

  37. 37.

    , & Canonical sampling through velocity rescaling. J. Chem. Phys. 126, 14101 (2007).

  38. 38.

    et al.. A smooth particle mesh Ewald method. J. Chem. Phys. 103, 8577–8593 (1995).

  39. 39.

    , , & GROMACS 4: algorithms for highly efficient, load-balanced, and scalable molecular simulation. J. Chem. Theory Comput. 4, 435–447 (2008).

  40. 40.

    & Higher-order approximations for the particle-particle propagator. Z. Phys. A 317, 267–279 (1984).

  41. 41.

    , , & Intermediate state representation approach to physical properties of dicationic states. J. Chem. Phys. 135, 154113 (2011).

  42. 42.

    Gaussian basis functions for use in molecular calculations. I. Contraction of (9s5p) atomic basis sets for the first-row atoms. J. Chem. Phys. 53, 2823–2833 (1970).

  43. 43.

    , & Electron affinities of the first-row atoms revisited. Systematic basis sets and wave functions. J. Chem. Phys. 96, 6796–6806 (1992).

  44. 44.

    , & Many dicationic states and two-hole population analysis as a bridge to Auger spectra: strong localization phenomena in BF3. J. Chem. Phys. 94, 523–532 (1991).

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Acknowledgements

E.M. and P.S. thank Czech Science Foundation for support (project number 13-34168S). N.V.K. and L.S.C. gratefully acknowledge financial support from the Deutsche Forschungsgemeinschaft. L.S.C also gratefully acknowledges funding from the European Research Council (Advanced Investigator Grant no. 692657). I.U., M.N.P. and B.W. gratefully acknowledge support from the Deutsche Forschungsgemeinschaft (DFG Research Unit FOR 1789). The authors thank the BESSY II staff for assistance during the beamtimes. We thank E. Pluhařová for valuable discussions.

Author information

Author notes

    • Isaak Unger
    •  & Stephan Thürmer

    Present addresses: Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden (I.U.); Department of Chemistry, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto 606-8502, Japan (S.T.)

Affiliations

  1. Helmholtz-Zentrum Berlin für Materialien und Energie, Institute of Methods for Material Development, Albert-Einstein-Strasse 15, D-12489 Berlin, Germany

    • Isaak Unger
    • , Robert Seidel
    • , Stephan Thürmer
    • , Marvin N. Pohl
    • , Emad F. Aziz
    •  & Bernd Winter
  2. Department of Physics, Freie Universität Berlin, Arnimallee 14, D-14159 Berlin, Germany

    • Emad F. Aziz
  3. School of Chemistry, Monash University, Victoria 3800, Australia

    • Emad F. Aziz
  4. Theoretische Chemie, Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg, Germany

    • Lorenz S. Cederbaum
    •  & Nikolai V. Kryzhevoi
  5. Department of Physical Chemistry, University of Chemistry and Technology, Technická 5, 16628 Prague, Czech Republic

    • Eva Muchová
    •  & Petr Slavíček

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Contributions

I.U., R.S., S.T., M.N.P. and B.W. conceived, designed and performed the experiments, and analysed the experimental data. E.M. and P.S. performed and analysed the molecular dynamics simulations. N.V.K. computed the theoretical ETMD spectra and analysed them. B.W., P.S. and N.V.K. co-wrote the paper. All authors discussed the results and commented on the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Petr Slavíček or Bernd Winter or Nikolai V. Kryzhevoi.

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DOI

https://doi.org/10.1038/nchem.2727

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