Characterizing the innate dynamics of a gold NP via machine learning of atomic environments As a first representative example of ideal Au NPs, we investigate, analyze and reconstruct the innate atomic dynamics of a 309-atoms icosahedron (Ih 309 ) at various temperatures. An icosahedral NP can be imagined as a series of concentric shells that envelop a single central atom. The first shell that resembles an icosahedron is constituted by the first 12 atoms surrounding the central one. Larger icosahedra can be generated by adding further surrounding atomic shells, while at each new larger shell, the NP resembles more and more the ideal platonic solid with 20 equilateral triangles as faces and 12 vertexes. Ideal atomic icosahedral NPs can be thus obtained as composed of 13, 55, 147, 309, 561, 923, etc., atoms) -the so-called "magic atomic numbers" for icosahedral NPs. As a relevant example, here we start by studying the behavior of an ideal Au icosahedral NP composed of 309 atoms (Figure : Ih 309 ) at different temperatures via classical molecular dynamics (MD) simulations.