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Computational prediction of L_{3} EXAFS spectra of gold nanoparticles from classical molecular dynamics simulations

Computational prediction of L_{3} EXAFS spectra of gold nanoparticles from classical molecular dynamics simulations
Computational prediction of L_{3} EXAFS spectra of gold nanoparticles from classical molecular dynamics simulations
We present a computational approach for the simulation of extended x-ray absorption fine structure (EXAFS) spectra of nanoparticles directly from molecular dynamics simulations without fitting any of the structural parameters of the nanoparticle to experimental data. The calculation consists of two stages. First, a molecular dynamics simulation of the nanoparticle is performed and then the EXAFS spectrum is computed from “snapshots” of structures extracted from the simulation. A probability distribution function approach calculated directly from the molecular dynamics simulations is used to ensure a balanced sampling of photoabsorbing atoms and their surrounding scattering atoms while keeping the number of EXAFS calculations that need to be performed to a manageable level. The average spectrum from all configurations and photoabsorbing atoms is computed as an Au L3-edge EXAFS spectrum with the FEFF 8.4 package, which includes the self-consistent calculation of atomic potentials. We validate and apply this approach in simulations of EXAFS spectra of gold nanoparticles with sizes between 20 and 60 Å. We investigate the effect of size, structural anisotropy, and thermal motion on the gold nanoparticle EXAFS spectra and we find that our simulations closely reproduce the experimentally determined spectra.
1550-235X
115409-[8pp]
Roscioni, Otello Maria
1e75cd73-a2ed-4e6a-9f8f-25c9ffe1e271
Zonias, Nicholas
c1b6fb01-4048-4751-8b40-65e5363adbd5
Price, Stephen W.T.
5d3310d0-cf30-45e6-ba44-4bf87ade3b8d
Russell, Andrea E.
b6b7c748-efc1-4d5d-8a7a-8e4b69396169
Comaschi, Tatiana
7f02045a-10b5-4ed5-9806-4648f6a6d917
Skylaris, Chris-Kriton
8f593d13-3ace-4558-ba08-04e48211af61
Roscioni, Otello Maria
1e75cd73-a2ed-4e6a-9f8f-25c9ffe1e271
Zonias, Nicholas
c1b6fb01-4048-4751-8b40-65e5363adbd5
Price, Stephen W.T.
5d3310d0-cf30-45e6-ba44-4bf87ade3b8d
Russell, Andrea E.
b6b7c748-efc1-4d5d-8a7a-8e4b69396169
Comaschi, Tatiana
7f02045a-10b5-4ed5-9806-4648f6a6d917
Skylaris, Chris-Kriton
8f593d13-3ace-4558-ba08-04e48211af61

Roscioni, Otello Maria, Zonias, Nicholas, Price, Stephen W.T., Russell, Andrea E., Comaschi, Tatiana and Skylaris, Chris-Kriton (2011) Computational prediction of L_{3} EXAFS spectra of gold nanoparticles from classical molecular dynamics simulations. Physical Review B, 83 (11), 115409-[8pp]. (doi:10.1103/PhysRevB.83.115409).

Record type: Article

Abstract

We present a computational approach for the simulation of extended x-ray absorption fine structure (EXAFS) spectra of nanoparticles directly from molecular dynamics simulations without fitting any of the structural parameters of the nanoparticle to experimental data. The calculation consists of two stages. First, a molecular dynamics simulation of the nanoparticle is performed and then the EXAFS spectrum is computed from “snapshots” of structures extracted from the simulation. A probability distribution function approach calculated directly from the molecular dynamics simulations is used to ensure a balanced sampling of photoabsorbing atoms and their surrounding scattering atoms while keeping the number of EXAFS calculations that need to be performed to a manageable level. The average spectrum from all configurations and photoabsorbing atoms is computed as an Au L3-edge EXAFS spectrum with the FEFF 8.4 package, which includes the self-consistent calculation of atomic potentials. We validate and apply this approach in simulations of EXAFS spectra of gold nanoparticles with sizes between 20 and 60 Å. We investigate the effect of size, structural anisotropy, and thermal motion on the gold nanoparticle EXAFS spectra and we find that our simulations closely reproduce the experimentally determined spectra.

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Published date: 15 March 2011

Identifiers

Local EPrints ID: 179177
URI: http://eprints.soton.ac.uk/id/eprint/179177
ISSN: 1550-235X
PURE UUID: 75729cd1-1968-4c83-9235-999ed4d52f20
ORCID for Andrea E. Russell: ORCID iD orcid.org/0000-0002-8382-6443
ORCID for Chris-Kriton Skylaris: ORCID iD orcid.org/0000-0003-0258-3433

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Date deposited: 04 Apr 2011 10:32
Last modified: 15 Mar 2024 02:58

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Contributors

Author: Otello Maria Roscioni
Author: Nicholas Zonias
Author: Stephen W.T. Price
Author: Tatiana Comaschi

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