ON SIZE DEPENDENCE OF THE SURFACE ENERGY OF GOLD NANOCLUSTERS: MONTE-CARLO STUDY USING GUPTA MULTIPARTICLE POTENTIAL

In recent years, there was achieved a significant progress both in the theory and in the development of numerical algorithms in the physics of condensed media. One of the directions of the computer simulation of the properties of metals, including the study of the solid–liquid phase transition, is the application of the Monte Carlo (MC) method with semi empirical potentials, whose parameters are adjusted based on experimental data, which, as a rule, relate to the bulk phase. The Gupta potential [1] is frequently employed in the calculations of the properties of metallic nanoclusters. The effective specific total surface energy ε is defined as where is the excess energy of the small object in comparison with the corresponding bulk phase, is the radius of the chosen divided surface. On the one hand, we found that increases with growth of following, in an approximation, to linear formula . For the surface tension analogous formula was obtained in frames of surface thermodynamics by A.I. Rusanov [2] ( and are constants depending on the temperature and the pressure). On the other hand, the dependence is satisfactorily described by the well-known Tolman formula if one replaces by . According to the obtained curve, at for ; for and for . The last value of amounts 93% of the bulk value recalculated using the experimental value of the surface tension .

Acknowledgments

Financial support of Ministry for Education and Science of Russian Federation is acknowledged (grant program ‘Scientific and pedagogical stuff of the innovation Russia, 2009-2013’).

References :

1. R. P. Gupta, Phys. Rev. B: Condens. Matter, 1981, 23, 12, 6265–6270

2. Rusanov A.I. Thermodynamics of surface phemonena. Leningrad, Leningrad State university Ed., 1960 (in Russian)

3. Tolman R.C. J. Chem. Physics, 1949, 17, 2, 333–337.