Structure of oxidised silver (1 1 1) and (1 1 0) surfaces

Sara B. Isbill, Sharani Roy, David J. Keffer

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

An exhaustive suite of classical molecular dynamics simulations is performed to investigate the stability of oxygen on silver (1 1 1) and (1 1 0) surfaces as a function of surface/subsurface location, binding site, fractional occupancy, and temperature. The ReaxFF potential is used to allow charge transfer between the oxygen and silver components. Comparison of the binding energies at various sites from ReaxFF and ab initio calculations reveals partial agreement between the two approaches. For many of the conditions sampled in the current study, we observe an initial state gives rise to a more disordered reconstruction, which is energetically more favourable. The driving force behind this reconstruction is largely an increase in the coordination of O by Ag, resulting in a more favourable binding site. The extent of reconstruction and atomic motion that initiates the reconstructive process is highly dependent on surface type, fractional occupancy, initially occupied site and temperature. For example, in the temperature range studied (77–500 K), on Ag(1 1 1) it is fractional occupancy that predominantly dictates the type and extent of reconstruction. However, on Ag(1 1 0) it is temperature rather than fractional coverage that is seen to have a more influential effect on the extent of surface reconstruction. These simulations clearly show that O atoms move from surface to subsurface sites, as has been observed experimentally.

Original languageEnglish
Pages (from-to)355-369
Number of pages15
JournalMolecular Simulation
Volume43
Issue number5-6
DOIs
StatePublished - Apr 13 2017
Externally publishedYes

Funding

This work was supported by the University of Tennessee. This work was done on the Newton high-performance computing cluster located at the University of Tennessee, Knoxville. The authors would like to thank the main administrator of Newton, Dr. Gerald Ragghianti, for his assistance throughout the semester, as well as Nick McNutt for the installation of LAMMPS and Marshall McDonnell for codes used during data analysis. They also thank the following students in the Modeling & Simulation in Materials Science & Engineering: Classical Mechanics graduate-level course for assisting in running the suite of 153 calculations: Ashleigh Barnes, Andrea Becker, Randi Beil, Zachary Bergstrom, Peiyong Chen, Harkiran Dhah, Yongjie Ding, Matt Dutra, Marie Kirkegaard, Chang Liu, Mansi Lu, Andrew Lubimtsev, Artem Maksov, Drew Marable, Baker Martin, Carly McKown, Kristian Myhre, Ali Nobakht, Hasan Rezayat, John Salasin, Brandon Shaver, Weimin Song, Jeremy Tisdale, Jiaqi Wang, and Shao-Yu Wang. SBI and SR are grateful for financial support from the University of Tennessee, Knoxville.

Keywords

  • Silver
  • molecular dynamics
  • oxide
  • surface

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