An effective method to calculate atomic movements in 3D objects with tuneable stochasticity (3DO-SKMF),☆☆

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Abstract

We present an effective computer simulation method, called 3D object stochastic kinetic modelling framework (3DO-SKMF), to calculate atomic movements in 3D objects including surface segregation and Gibbs–Thomson effect (surface curvature). Objects with any kind of shapes can easily be considered thanks to the flexibility and versatility of the model and code. Accordingly, the model and the computer code can be used in a wide variety of applications: nanoparticles, nanorods, nanotubes, nanopillars, etc. To increase the versatility of the model, it includes stochastic noise in a tuneable manner. This means that if the noise level is zero, the model is completely deterministic (mean-field), whereas by increasing the noise level the result gets closer and closer to that obtained by a kinetic Monte Carlo calculation. This allows us to calculate processes with activation barriers. Besides demonstrating the capabilities of the model, we also reproduce an experimental result showing decomposition of Ag–Cu nanoparticles.

Program summary

Program title: 3DO-SKMF

CPC Library link to program files: http://dx.doi.org/10.17632/776b7txmhv.1

Licensing provisions: CC BY NC 3.0

Programming language: ISO C

Nature of problem: Atomistic simulation of nano-objects with free surfaces by calculating occupation probabilities. The model includes surface segregation and Gibbs–Thomson effect (surface curvature).

Solution method: Numerical solution of a system of differential equations with taking into account the conservation of matter. The number of equations is equal to the number of lattice sites in a 3D lattice.

Additional comments including restrictions and unusual features: The model contains parameters that can be determined from macroscopic measurements, still in the background it follows an atomistic approach. Note that the provided code is written for nanospheres (hollow and solid), nanowires and nanotubes, however objects with any kind of shapes can easily be considered. Due to the flexibility of the code, with minor change of initialization, any 3D object can be simulated. The published code uses the face centred cubic lattice (fcc), its modification for other lattices is, however, straightforward.

Keywords

3D object stochastic kinetic modelling framework (3DO-SKMF)
Surface segregation
Nanoparticle
Nanowire
Core–shell
Gibbs–Thomson
Surface curvature

Cited by (0)

The review of this paper was arranged by Prof. D.P. Landau.

☆☆

This paper and its associated computer program are available via the Computer Physics Communication homepage on ScienceDirect (http://www.sciencedirect.com/science/journal/00104655)