scholarly journals Ion Pairing and Multiple Ion Binding in Calcium Carbonate Solutions Based on a Polarizable AMOEBA Force Field and Ab Initio Molecular Dynamics

2020 ◽  
Vol 124 (17) ◽  
pp. 3568-3582 ◽  
Author(s):  
Paolo Raiteri ◽  
Alicia Schuitemaker ◽  
Julian D. Gale
Keyword(s):  
Molecular Dynamics ◽  
Calcium Carbonate ◽  
Force Field ◽  
Ab Initio ◽  
Ion Pairing ◽  
Ab Initio Molecular Dynamics ◽  
Ion Binding ◽  
Carbonate Solutions ◽  
Amoeba Force Field

scholarly journals Ion Pairing and Multiple Ion Binding in Calcium Carbonate Solutions Based on a Polarizable AMOEBA Force Field and Ab Initio Molecular Dynamics

2020 ◽  
Author(s):  
Paolo Raiteri ◽  
Alicia Schuitemaker ◽  
Julian Gale
Keyword(s):  
Molecular Dynamics ◽  
Calcium Carbonate ◽  
Force Field ◽  
Ab Initio ◽  
Ion Pairs ◽  
Ion Pairing ◽  
Ab Initio Molecular Dynamics ◽  
Carbonate Solutions ◽  
Multiple Binding ◽  
Carbonate Species

The speciation of calcium carbonate in water is important to the geochemistry of the world’s oceans and has ignited significant debate regarding the mechanism by which nucleation occurs. Here it is vital to be able to quantify the thermodynamics of ion pairing versus higher order association processes in order to distinguish between possible pathways. Given that it is experimentally challenging to quantify such species, here we determine the thermodynamics for ion pairing and multiple binding of calcium carbonate species using bias-enhanced molecular dynamics. In order to examine the uncertainties underlying these results, we have derived a new polarizable force field for both calcium carbonate and bicarbonate in water based on the AMOEBA model to compare against our earlier rigid-ion model, both of which are further benchmarked against ab initio molecular dynamics for the ion pair. Both force fields consistently indicate that the association of calcium carbonate ion pairs is stable, though with an equilibrium constant that is lower than for ion pairing itself.

scholarly journals Ion Pairing and Multiple Ion Binding in Calcium Carbonate Solutions Based on a Polarizable AMOEBA Force Field and Ab Initio Molecular Dynamics

2020 ◽  
Author(s):  
Paolo Raiteri ◽  
Alicia Schuitemaker ◽  
Julian Gale
Keyword(s):  
Molecular Dynamics ◽  
Calcium Carbonate ◽  
Force Field ◽  
Ab Initio ◽  
Ion Pairs ◽  
Ion Pairing ◽  
Ab Initio Molecular Dynamics ◽  
Carbonate Solutions ◽  
Multiple Binding ◽  
Carbonate Species

The speciation of calcium carbonate in water is important to the geochemistry of the world’s oceans and has ignited significant debate regarding the mechanism by which nucleation occurs. Here it is vital to be able to quantify the thermodynamics of ion pairing versus higher order association processes in order to distinguish between possible pathways. Given that it is experimentally challenging to quantify such species, here we determine the thermodynamics for ion pairing and multiple binding of calcium carbonate species using bias-enhanced molecular dynamics. In order to examine the uncertainties underlying these results, we have derived a new polarizable force field for both calcium carbonate and bicarbonate in water based on the AMOEBA model to compare against our earlier rigid-ion model, both of which are further benchmarked against ab initio molecular dynamics for the ion pair. Both force fields consistently indicate that the association of calcium carbonate ion pairs is stable, though with an equilibrium constant that is lower than for ion pairing itself.

scholarly journals Ion Pairing and Multiple Ion Binding in Calcium Carbonate Solutions Based on a Polarizable AMOEBA Force Field and Ab Initio Molecular Dynamics

2020 ◽  
Author(s):  
Paolo Raiteri ◽  
Alicia Schuitemaker ◽  
Julian Gale
Keyword(s):  
Molecular Dynamics ◽  
Calcium Carbonate ◽  
Force Field ◽  
Ab Initio ◽  
Ion Pairs ◽  
Ion Pairing ◽  
Ab Initio Molecular Dynamics ◽  
Carbonate Solutions ◽  
Multiple Binding ◽  
Carbonate Species

The speciation of calcium carbonate in water is important to the geochemistry of the world’s oceans and has ignited significant debate regarding the mechanism by which nucleation occurs. Here it is vital to be able to quantify the thermodynamics of ion pairing versus higher order association processes in order to distinguish between possible pathways. Given that it is experimentally challenging to quantify such species, here we determine the thermodynamics for ion pairing and multiple binding of calcium carbonate species using bias-enhanced molecular dynamics. In order to examine the uncertainties underlying these results, we have derived a new polarizable force field for both calcium carbonate and bicarbonate in water based on the AMOEBA model to compare against our earlier rigid-ion model, both of which are further benchmarked against ab initio molecular dynamics for the ion pair. Both force fields consistently indicate that the association of calcium carbonate ion pairs is stable, though with an equilibrium constant that is lower than for ion pairing itself.

A new universal force-field for the Li2S-P2S5 system

2022 ◽  
Author(s):  
Shunsuke Ariga ◽  
Takahiro Ohkubo ◽  
Shingo Urata ◽  
Yutaka Imamura ◽  
Taketoshi Taniguchi
Keyword(s):  
Molecular Dynamics ◽  
Solid State ◽  
Force Field ◽  
Ab Initio ◽  
Promising Material ◽  
Ab Initio Molecular Dynamics ◽  
Conduction Mechanisms ◽  
Universal Force Field ◽  
Solid State Batteries ◽  
All Solid State Batteries

Lithium thiophosphate electrolyte is a promising material for application in all-solid-state batteries. Ab initio molecular dynamics (AIMD) simulations have been used to investigate the ion conduction mechanisms in single-crystalline and...

scholarly journals Sulphur and Molybdenum Incorporation at the Calcite-Water Interface: Insights from Ab Initio Molecular Dynamics

2021 ◽  
Author(s):  
Scott D. Midgley ◽  
Devis Di Tommaso ◽  
Dominik Fleitmann ◽  
Ricardo Grau-Crespo
Keyword(s):  
Molecular Dynamics ◽  
Calcium Carbonate ◽  
Ab Initio ◽  
Mineral Water ◽  
Ab Initio Molecular Dynamics ◽  
Water Interface ◽  
Trace Impurities ◽  
Tetrahedral Oxyanions ◽  
Element Bearing ◽  
Tetrahedral Anion

<p>Sulphur and molybdenum trace impurities in speleothems (stalagmites and stalactites) can provide long and continuous records of volcanic activity, which are important for past climatic and environmental reconstructions. However, the chemistry governing the incorporation of the trace-element bearing species into the calcium carbonate phases forming speleothems is not well understood. Our previous work has shown that substitution as tetrahedral oxyanions [<i>X</i>O<sub>4</sub>]<sup>2-</sup> (<i>X</i>=S, Mo) replacing [CO<sub>3</sub>]<sup>2-</sup> in CaCO<sub>3</sub> bulk phases (except perhaps for vaterite) is thermodynamically unfavourable with respect to the formation of competing phases, due to the larger size and different shape of the [<i>X</i>O<sub>4</sub>]<sup>2- </sup>tetrahedral anions in comparison with the flat [CO<sub>3</sub>]<sup>2-</sup> anions, which implied that most of the incorporation would happen at the surface rather than the bulk of the mineral. Here we present an ab initio molecular dynamics study exploring the incorporation of these impurities at the mineral-water interface. We show that the oxyanions substitution at the aqueous calcite (10.4) surface is clearly favoured over bulk incorporation, due to the lower structural strain on the calcium carbonate solid. Incorporation at surface step sites is even more favourable for both oxyanions, thanks to the additional interface space afforded by the surface line defect to accommodate the tetrahedral anion. Differences between sulphate and molybdate substitution can be mostly explained by the size of the anions. The molybdate oxyanion is more difficult to incorporate in the calcite bulk than the smaller sulphate oxyanion. However, when molybdate is substituted at the surface, the elastic cost is avoided because the oxyanion protrudes out of the surface and gains stability via the interaction with water at the interface, which in balance results in more favourable surface substitution for molybdate than for sulphate. The detailed molecular-level insights provided by our calculations will be useful to understand the chemical basis of S- and Mo-based speleothem records.</p>

scholarly journals Calcium ions in aqueous solutions: Accurate force field description aided by ab initio molecular dynamics and neutron scattering

2018 ◽  
Vol 148 (22) ◽  
pp. 222813 ◽  
Author(s):  
Tomas Martinek ◽  
Elise Duboué-Dijon ◽  
Štěpán Timr ◽  
Philip E. Mason ◽  
Katarina Baxová ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Aqueous Solutions ◽  
Force Field ◽  
Neutron Scattering ◽  
Ab Initio ◽  
Calcium Ions ◽  
Ab Initio Molecular Dynamics

scholarly journals Sulphur and Molybdenum Incorporation at the Calcite-Water Interface: Insights from Ab Initio Molecular Dynamics

2021 ◽  
Author(s):  
Scott D. Midgley ◽  
Devis Di Tommaso ◽  
Dominik Fleitmann ◽  
Ricardo Grau-Crespo
Keyword(s):  
Molecular Dynamics ◽  
Calcium Carbonate ◽  
Ab Initio ◽  
Mineral Water ◽  
Ab Initio Molecular Dynamics ◽  
Water Interface ◽  
Trace Impurities ◽  
Tetrahedral Oxyanions ◽  
Element Bearing ◽  
Tetrahedral Anion

<p>Sulphur and molybdenum trace impurities in speleothems (stalagmites and stalactites) can provide long and continuous records of volcanic activity, which are important for past climatic and environmental reconstructions. However, the chemistry governing the incorporation of the trace-element bearing species into the calcium carbonate phases forming speleothems is not well understood. Our previous work has shown that substitution as tetrahedral oxyanions [<i>X</i>O<sub>4</sub>]<sup>2-</sup> (<i>X</i>=S, Mo) replacing [CO<sub>3</sub>]<sup>2-</sup> in CaCO<sub>3</sub> bulk phases (except perhaps for vaterite) is thermodynamically unfavourable with respect to the formation of competing phases, due to the larger size and different shape of the [<i>X</i>O<sub>4</sub>]<sup>2- </sup>tetrahedral anions in comparison with the flat [CO<sub>3</sub>]<sup>2-</sup> anions, which implied that most of the incorporation would happen at the surface rather than the bulk of the mineral. Here we present an ab initio molecular dynamics study exploring the incorporation of these impurities at the mineral-water interface. We show that the oxyanions substitution at the aqueous calcite (10.4) surface is clearly favoured over bulk incorporation, due to the lower structural strain on the calcium carbonate solid. Incorporation at surface step sites is even more favourable for both oxyanions, thanks to the additional interface space afforded by the surface line defect to accommodate the tetrahedral anion. Differences between sulphate and molybdate substitution can be mostly explained by the size of the anions. The molybdate oxyanion is more difficult to incorporate in the calcite bulk than the smaller sulphate oxyanion. However, when molybdate is substituted at the surface, the elastic cost is avoided because the oxyanion protrudes out of the surface and gains stability via the interaction with water at the interface, which in balance results in more favourable surface substitution for molybdate than for sulphate. The detailed molecular-level insights provided by our calculations will be useful to understand the chemical basis of S- and Mo-based speleothem records.</p>

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