Metallic nanoparticles meet Metadynamics

TL;DR

This paper demonstrates how Metadynamics combined with Molecular Dynamics can effectively explore the free energy landscape of metallic nanoparticles, revealing known and new structural transformation pathways.

Contribution

It introduces a novel application of Metadynamics with collective variables based on pair distance distribution functions for metallic and bimetallic nanoparticles.

Findings

Successfully sampled configurational space of Ag147 and Pt147 nanoparticles.

Reproduced known structural transformation pathways.

Predicted a new transformation route from icosahedron to anti-cuboctahedron.

Abstract

We show how standard Metadynamics coupled with classical Molecular Dynamics can be successfully ap- plied to sample the configurational and free energy space of metallic and bimetallic nanopclusters via the implementation of collective variables related to the pair distance distribution function of the nanoparticle itself. As paradigmatic examples we show an application of our methodology to Ag147, Pt147 and their alloy AgshellPtcore at 1:1 and 2:1 chemical compositions. The proposed scheme is not only able to reproduce known structural transformation pathways, as the five and the six square-diamond mechanisms both in pure and core-shell nanoparticles but also to predict a new route connecting icosahedron to anti-cuboctahedron.