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I want to study the effect of nitrogen interstitials on oxygen diffusion in metals and vice-versa. Would you suggest MSD calculations in LAMMPS to be a viable method for this? There aren't many interatomic potentials for different metals with N and O, so I am unsure where to start as well.

Any pointers would be a huge help, thanks.

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I assume that you want to model how the oxygen atom migrates or diffuses in the interstitial region of Ni-based metal. With the LAMMPS package, you are trying to solve this problem with classical molecular dynamics. How to interatomic potentials is important but kind of tricky. However, you can use the Nudged Elastic Band (NEB) method to find the migration path from the angle of the fist-principles.

The nudged elastic band (NEB) is a method for finding saddle points and minimum energy paths between known reactants and products. The method works by optimizing a number of intermediate images along the reaction path. Each image finds the lowest energy possible while maintaining equal spacing to neighboring images. This constrained optimization is done by adding spring forces along with the band between images and by projecting out the component of the force due to the potential perpendicular to the band.

In detail, you can use this method in the VASP package with the VTST function.

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  • $\begingroup$ Thank you so much for your time, and comment. VASP does look like the way to go for it. The research group I work in is not directly aligned to DFT/MD, and hence i was looking at open source packages like LAMMPS hoping to use those to solve this problem. Would you recommend any alternatives to VASP? $\endgroup$
    – Dr.Viper
    Nov 14 '20 at 15:27
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    $\begingroup$ @Dr.Viper Quantum Espresso/GPAW/CP2K $\endgroup$
    – Jack
    Nov 15 '20 at 1:02
  • $\begingroup$ Worked out with NEB.X in Quantum Espresso. Thank you @Jack $\endgroup$
    – Dr.Viper
    Dec 1 '20 at 1:59
  • $\begingroup$ @Dr.Viper You are welcome! $\endgroup$
    – Jack
    Dec 1 '20 at 2:08

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