Do water's electrons care about electrolytes?

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F60461373%3A22340%2F19%3A43918176" target="_blank" >RIV/60461373:22340/19:43918176 - isvavai.cz</a>

Result on the web

<a href="https://doi.org/10.1039/C8SC03381A" target="_blank" >https://doi.org/10.1039/C8SC03381A</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1039/c8sc03381a" target="_blank" >10.1039/c8sc03381a</a>

Result language

angličtina

Original language name

Do water's electrons care about electrolytes?

Original language description

Ions have a profound effect on the geometrical structure of liquid water and an aqueous environment is known to change the electronic structure of ions. Here we combine photoelectron spectroscopy measurements from liquid microjets with molecular dynamical and quantum chemical calculations to address the reverse question, to what extent do ions affect the electronic structure of liquid water? We study aqueous solutions of sodium iodide (NaI) over a wide concentration range, from nearly pure water to 8 M solutions, recording spectra in the 5 to 60 eV binding energy range to include all water valence and the solute Na + 2p, I - 4d, and I - 5p orbital ionization peaks. We observe that the electron binding energies of the solute ions change only slightly as a function of electrolyte concentration, less than 150 ± 60 meV over an ∼8 M range. Furthermore, the photoelectron spectrum of liquid water is surprisingly mildly affected as we transform the sample from a dilute aqueous salt solution to a viscous, crystalline-like phase. The most noticeable spectral changes are a negative binding energy shift of the water 1b 2 ionizing transition (up to -370 ± 60 meV) and a narrowing of the flat-top shape water 3a 1 ionization feature (up to 450 ± 90 meV). A novel computationally efficient technique is introduced to calculate liquid-state photoemission spectra using small clusters from molecular dynamics (MD) simulations embedded in dielectric continuum. This theoretical treatment captured the characteristic positions and structures of the aqueous photoemission peaks, reproducing the experimentally observed narrowing of the water 3a 1 feature and weak sensitivity of the water binding energies to electrolyte concentration. The calculations allowed us to attribute the small binding energy shifts to ion-induced disruptions of intermolecular electronic interactions. Furthermore, they demonstrate the importance of considering concentration-dependent screening lengths for a correct description of the electronic structure of solvated systems. Accounting for electronic screening, the calculations highlight the minimal effect of electrolyte concentration on the 1b 1 binding energy reference, in accord with the experiments. This leads us to a key finding that the isolated, lowest-binding-energy, 1b 1 , photoemission feature of liquid water is a robust energetic reference for aqueous liquid microjet photoemission studies.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10403 - Physical chemistry

Project

<a href="/en/project/GA18-23756S" target="_blank" >GA18-23756S: Transforming molecules with X-rays: Ab initio simulations in liquids</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2019

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Chemical Science

ISSN

2041-6520

e-ISSN

—

Volume of the periodical

10

Issue of the periodical within the volume

3

Country of publishing house

GB - UNITED KINGDOM

Number of pages

18

Pages from-to

848-865

UT code for WoS article

000457304200023

EID of the result in the Scopus database

2-s2.0-85059167600