Ionic diffusion and proton transfer of MgCl2 and CaCl2 aqueous solutions: an ab initio study under electric field

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68081707%3A_____%2F19%3A00504501" target="_blank" >RIV/68081707:_____/19:00504501 - isvavai.cz</a>

Výsledek na webu

<a href="https://www.tandfonline.com/doi/full/10.1080/08927022.2018.1513650" target="_blank" >https://www.tandfonline.com/doi/full/10.1080/08927022.2018.1513650</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1080/08927022.2018.1513650" target="_blank" >10.1080/08927022.2018.1513650</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Ionic diffusion and proton transfer of MgCl2 and CaCl2 aqueous solutions: an ab initio study under electric field

Popis výsledku v původním jazyce

We report on a series of ab initio molecular dynamics simulations on MgCl and CaCl aqueous solutions subjected to the effect of static electric fields. The diffusion properties of the solvated cationic species have been investigated both in the low-to-moderate field regime and for intense field strengths, where correlated proton transfers between the water molecules take place. Albeit the Grotthuss-like motion of the protons H dramatically affects the standard relative mobility of monovalent cations such as Li, Na, and K [Phys Chem Chem Phys 2017,19:20420], here we demonstrate that the rule 'the bigger the cation the higher its mobility' is preserved for divalent cations such as Mg and Ca even when a sustained protonic current is established by the field action. Notwithstanding the presence of charged particles anticipates the field threshold of the molecular dissociation of water from 0.35 V/angstrom to 0.25 V/angstrom, such a shift does not depend on the nominal charge the cations hold. Protons flow more easily in the MgCl solution (=2.3 S/cm) rather than in the CaCl (=1.7 S/cm) electrolyte solution because of a twofold reason. Firstly, Ca, being larger than Mg, more strongly hampers the propagation of a charge defect of the same sign (i.e. H). Secondly, we demonstrate that the mobility of Ca is sizably higher than that of Mg. This way, by spanning more efficiently the aqueous environment, Ca further inhibits the proton transfers along the H-bonded network. Finally, the protonic conduction efficiency is inversely proportional both to the ionic radii and to the nominal charge of the cations present in solution.

Název v anglickém jazyce

Ionic diffusion and proton transfer of MgCl2 and CaCl2 aqueous solutions: an ab initio study under electric field

Popis výsledku anglicky

We report on a series of ab initio molecular dynamics simulations on MgCl and CaCl aqueous solutions subjected to the effect of static electric fields. The diffusion properties of the solvated cationic species have been investigated both in the low-to-moderate field regime and for intense field strengths, where correlated proton transfers between the water molecules take place. Albeit the Grotthuss-like motion of the protons H dramatically affects the standard relative mobility of monovalent cations such as Li, Na, and K [Phys Chem Chem Phys 2017,19:20420], here we demonstrate that the rule 'the bigger the cation the higher its mobility' is preserved for divalent cations such as Mg and Ca even when a sustained protonic current is established by the field action. Notwithstanding the presence of charged particles anticipates the field threshold of the molecular dissociation of water from 0.35 V/angstrom to 0.25 V/angstrom, such a shift does not depend on the nominal charge the cations hold. Protons flow more easily in the MgCl solution (=2.3 S/cm) rather than in the CaCl (=1.7 S/cm) electrolyte solution because of a twofold reason. Firstly, Ca, being larger than Mg, more strongly hampers the propagation of a charge defect of the same sign (i.e. H). Secondly, we demonstrate that the mobility of Ca is sizably higher than that of Mg. This way, by spanning more efficiently the aqueous environment, Ca further inhibits the proton transfers along the H-bonded network. Finally, the protonic conduction efficiency is inversely proportional both to the ionic radii and to the nominal charge of the cations present in solution.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10301 - Atomic, molecular and chemical physics (physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect)

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2019

Kód důvěrnosti údajů

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

Název periodika

Molecular Simulation

ISSN

0892-7022

e-ISSN

—

Svazek periodika

45

Číslo periodika v rámci svazku

4-5

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

8

Strana od-do

373-380

Kód UT WoS článku

000460668700012

EID výsledku v databázi Scopus

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