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Bonding, structural and thermodynamic analysis of dissociative adsorption of H3O+ ion onto calcite (10 1 ¯ 4) surface: CPMD and DFT calculations

Ghatee, M. H ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1007/s00894-017-3499-1
  3. Abstract:
  4. We used density functional theory (DFT) and Car-Parrinello molecular dynamics (CPMD) simulation to investigate the adsorption and bond formation of hydronium ion (H3O+) onto a (10 1 ¯ 4) calcite surface. For surface coverage of 25% to 100%, the nature of H3O+ interaction was explored through electron density and energetics in the context of bond critical points. The adsorbate–adsorbent structure was studied by simulation of pair correlation function. The results revealed that dissociation into water molecule(s) and proton(s) complements H3O+ ion(s) adsorbtion. The H2O molecule adsorbs onto the surface via its O atom, and interacts with surface calcium in a closed-shell mode; the H+ ion makes a covalent bond to the surface oxygen while maintaining H-bonding with water. Adsorption energies were diminished by 70–90 kJ mol−1 when Obridge-bonded H+ ions transferred to the Oterminal manually. While dissociative adsorption of H3O+ ions is spontaneous at all surface coverages tested, the free energy was lowest at 75% coverage. Also, protonation of a completely pre-hydrated calcite surface leads to stronger interaction of water molecules with the surface. This unique outlook on hydrating calcite provides specific insights into biomineralization of this mineral, and helps depict further pH consequences in the field of biomaterial adsorption. [Figure not available: see fulltext.]. © 2017, Springer-Verlag GmbH Germany
  5. Keywords:
  6. (10 1 ¯ 4) calcite surface ; CPMD simulation ; DFT calculation ; Dissociative adsorption ; NBO and bond critical point ; Thermodynamic analysis ; Water and hydronium ion ; Adsorbent ; Calcium carbonate ; Hydronium ion ; Water ; Adsorption ; Biomineralization ; Chemical binding ; Chemical interaction ; Chemical structure ; Correlation function ; Covalent bond ; Density functional theory ; Dissociation ; Energy transfer ; Molecular dynamics ; Priority journal ; Proton transport ; Simulation ; Structure analysis ; Surface property ; Thermodynamics
  7. Source: Journal of Molecular Modeling ; Volume 23, Issue 12 , 2017 ; 16102940 (ISSN)
  8. URL: https://link.springer.com/article/10.1007%2Fs00894-017-3499-1