Ionic adsorption on the brucite (0001) surface:a periodic electrostatic embedded cluster method study

Makkos, Eszter and Kerridge, Andrew and Austin, Jonathan and Kaltsoyannis, Nikolas (2016) Ionic adsorption on the brucite (0001) surface:a periodic electrostatic embedded cluster method study. Journal of Chemical Physics, 145. ISSN 0021-9606

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Abstract

Density functional theory (DFT) at the generalised gradient approximation level is employed within the periodic electrostatic embedded cluster method (PEECM) to model the brucite (0001) surface. Three representative studies are then used to demonstrate the reliability of the PEECM for the description of the interactions of various ionic species with the layered Mg(OH)2 structure, and its performance is compared with periodic DFT, an approach known to be challenging for the adsorption of charged species. The adsorption energies of a series of s block cations, including Sr2+ and Cs+ which are known to coexist with brucite in nuclear waste storage ponds, are well described by the embedded cluster model, provided that basis sets of triple-zeta quality are employed for the adsorbates. The substitution energies of Ca2+ and Sr2+ into brucite obtained with the PEECM are very similar to periodic DFT results, and comparison of the approaches indicates that two brucite layers in the quantum mechanical part of the PEECM are sufficient to describe the substitution. Finally, a detailed comparison of the periodic and PEECM DFT approaches to the energetic and geometric properties of differently coordinated Sr[(OH)2(H2O)4] complexes on brucite shows an excellent agreement in adsorption energies, Sr–O distances, and bond critical point electron densities (obtained via the quantum theory of atoms-in-molecules), demonstrating that the PEECM can be a useful alternative to periodic DFT in these situations.

Item Type:
Journal Article
Journal or Publication Title:
Journal of Chemical Physics
Additional Information:
Copyright 2016 American Institute of Physics. The following article appeared in Journal of Chemical Physics, 145, 2016 and may be found at http://dx.doi.org/10.1063/1.4968035 This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1600/1606
Subjects:
ID Code:
83076
Deposited By:
Deposited On:
22 Nov 2016 13:48
Refereed?:
Yes
Published?:
Published
Last Modified:
25 Sep 2020 02:51