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Probing aqueous ions with non-local Auger relaxation

Gopakumar, Geethanjali ; Muchová, Eva ; Unger, Isaak ; Malerz, Sebastian ; Trinter, Florian ; Öhrwall, Gunnar LU orcid ; Lipparini, Filippo ; Mennucci, Benedetta ; Céolin, Denis and Caleman, Carl , et al. (2022) In Physical Chemistry Chemical Physics 24(15). p.8661-8671
Abstract

Non-local analogues of Auger decay are increasingly recognized as important relaxation processes in the condensed phase. Here, we explore non-local autoionization, specifically Intermolecular Coulombic Decay (ICD), of a series of aqueous-phase isoelectronic cations following 1s core-level ionization. In particular, we focus on Na+, Mg2+, and Al3+ ions. We unambiguously identify the ICD contribution to the K-edge Auger spectrum. The different strength of the ion-water interactions is manifested by varying intensities of the respective signals: the ICD signal intensity is greatest for the Al3+ case, weaker for Mg2+, and absent for weakly-solvent-bound Na+. With the... (More)

Non-local analogues of Auger decay are increasingly recognized as important relaxation processes in the condensed phase. Here, we explore non-local autoionization, specifically Intermolecular Coulombic Decay (ICD), of a series of aqueous-phase isoelectronic cations following 1s core-level ionization. In particular, we focus on Na+, Mg2+, and Al3+ ions. We unambiguously identify the ICD contribution to the K-edge Auger spectrum. The different strength of the ion-water interactions is manifested by varying intensities of the respective signals: the ICD signal intensity is greatest for the Al3+ case, weaker for Mg2+, and absent for weakly-solvent-bound Na+. With the assistance of ab initio calculations and molecular dynamics simulations, we provide a microscopic understanding of the non-local decay processes. We assign the ICD signals to decay processes ending in two-hole states, delocalized between the central ion and neighbouring water. Importantly, these processes are shown to be highly selective with respect to the promoted water solvent ionization channels. Furthermore, using a core-hole-clock analysis, the associated ICD timescales are estimated to be around 76 fs for Mg2+ and 34 fs for Al3+. Building on these results, we argue that Auger and ICD spectroscopy represents a unique tool for the exploration of intra- and inter-molecular structure in the liquid phase, simultaneously providing both structural and electronic information.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Chemistry Chemical Physics
volume
24
issue
15
pages
11 pages
publisher
Royal Society of Chemistry
external identifiers
  • pmid:35356960
  • scopus:85128232498
ISSN
1463-9076
DOI
10.1039/d2cp00227b
language
English
LU publication?
yes
id
7be1cb7f-ab0a-48e1-b45e-eb923aac18fb
date added to LUP
2022-07-06 13:58:54
date last changed
2024-06-14 12:33:58
@article{7be1cb7f-ab0a-48e1-b45e-eb923aac18fb,
  abstract     = {{<p>Non-local analogues of Auger decay are increasingly recognized as important relaxation processes in the condensed phase. Here, we explore non-local autoionization, specifically Intermolecular Coulombic Decay (ICD), of a series of aqueous-phase isoelectronic cations following 1s core-level ionization. In particular, we focus on Na<sup>+</sup>, Mg<sup>2+</sup>, and Al<sup>3+</sup> ions. We unambiguously identify the ICD contribution to the K-edge Auger spectrum. The different strength of the ion-water interactions is manifested by varying intensities of the respective signals: the ICD signal intensity is greatest for the Al<sup>3+</sup> case, weaker for Mg<sup>2+</sup>, and absent for weakly-solvent-bound Na<sup>+</sup>. With the assistance of ab initio calculations and molecular dynamics simulations, we provide a microscopic understanding of the non-local decay processes. We assign the ICD signals to decay processes ending in two-hole states, delocalized between the central ion and neighbouring water. Importantly, these processes are shown to be highly selective with respect to the promoted water solvent ionization channels. Furthermore, using a core-hole-clock analysis, the associated ICD timescales are estimated to be around 76 fs for Mg<sup>2+</sup> and 34 fs for Al<sup>3+</sup>. Building on these results, we argue that Auger and ICD spectroscopy represents a unique tool for the exploration of intra- and inter-molecular structure in the liquid phase, simultaneously providing both structural and electronic information.</p>}},
  author       = {{Gopakumar, Geethanjali and Muchová, Eva and Unger, Isaak and Malerz, Sebastian and Trinter, Florian and Öhrwall, Gunnar and Lipparini, Filippo and Mennucci, Benedetta and Céolin, Denis and Caleman, Carl and Wilkinson, Iain and Winter, Bernd and Slavíček, Petr and Hergenhahn, Uwe and Björneholm, Olle}},
  issn         = {{1463-9076}},
  language     = {{eng}},
  month        = {{03}},
  number       = {{15}},
  pages        = {{8661--8671}},
  publisher    = {{Royal Society of Chemistry}},
  series       = {{Physical Chemistry Chemical Physics}},
  title        = {{Probing aqueous ions with non-local Auger relaxation}},
  url          = {{http://dx.doi.org/10.1039/d2cp00227b}},
  doi          = {{10.1039/d2cp00227b}},
  volume       = {{24}},
  year         = {{2022}},
}