The Surface Free Energies of Solid Chemical Elements: Calculation from Internal Free Enthalpies of Atomization

Abstract

It is pointed out that the experimentally-measured quantity usually termed “surface free energy” is in fact a part of the free enthalpy which is due to the presence of the surface (referred to unit surface). This quantity, denoted by γ i o for the polycrystalline solid chemical element i, is connected to the internal free enthalpy of atomization Δ G a,i * by the relation γ i o φ i o =α i o Δ G a,i * where φ i o is the molar surface area, and α i o is a constant. Its physical meaning is given to a relatively good approximation. Approximate methods of calculation based on experimental data give values of α i o at any temperature for metallic, semimetallic and covalently-bonded solid chemical elements. Using these procedures, the values of γ i o at 298.2 K and at the melting temperature are tabulated.