(360ay) Parameterization of C, Si, and Ge in the Common Harmonic Form for Molecular Dynamics Simulations

The Interface Force Field (IFF) project focuses on an all-atom force field and surface model database for simulation of nanostructures of 1 to 1000 nm size, including minerals, metals, oxides, and (bio)polymers in high accuracy.¹ To achieve this aim, the IFF project develops interpretable models and parameters to simulate bulk and surface properties, including complex mixtures and reactivity (IFF-R).

In this work, we parameterized C, Si, and Ge using a common harmonic energy expression by representing the tetrahedral localized bonding with ancillary, low-mass, virtual electrons. The innovation lies in the representation of covalent-type bonds through a combination of virtual electrons and Lennard-Jones parameters. The models show some promise to describe these structures consistently. Assembling the atomic units into cubic crystals, we calculate density, melting point, constant pressure heat capacity, surface energy, and bulk modulus within 5% of experimental values. Our models accurately reproduce the bulk and surface properties of group-14 elemental crystals while retaining compatibility with existing organic and biological forcefields, allowing molecular dynamics simulations of inorganic/organic systems, mixed phases, and alloys.

References:

(1) Heinz, H., Lin, T.-J., Kishore Mishra, R., & Emami, F. S. (2013). Thermodynamically Consistent Force Fields for the Assembly of Inorganic, Organic, and Biological Nanostructures: The INTERFACE Force Field. Langmuir, 29(6), 1754–1765. https://doi.org/10.1021/la3038846