Freezing and Melting of Silver Nanoparticles on Silica Substrate Using a Simple Interatomic Potential for Ag-SiO2 Interaction on the Basis of ab Initio Calculations and Experimental Data

silica eta(amorph)= 2.5. This potential is thought to be useful to investigate the effect of the silica support on the structure and morphology of deposited silver nanoparticles. As an example, we study theWe have devised a Ag-Sio(2) potential for Monte Carlo and molecular dynamics studies of systems comprising silver nano particles in contact with silica surfaces. The potential is determined based on density functional theory (DFT) calculations on beta-cristobalite, a silica crystal, as well as theoretical and experimental data on alpha-quartz and amorphous silica found in literature. The interactions between Ag and silica species are fitted with the simple Lennard-Jones (12, 6) potential with parameters sigma(Ag-o) = 0.278 nm, sigma(Ag-Si) = 0.329 nm, epsilon(Ag-o) = 0.012 eV, and epsilon(Ag-Si) = 0.002 eV. The nature of the substrate is taken into account at a phenomenological level as an extra multiplicative factor for eta the total interaction between silver and silica: for alpha-quartz eta(quartz) = 1, for hydroxylated beta-cristobalite eta(crist) = 5.0, and for amorphoussilica eta(amorph) = 2.5. This potential is thought to be useful to investigate the effect of the silica support on the structure and morphology of deposited silver nanoparticles. As an example, we study the melting and freezing of supported nanoparticles. This potential could also possibly be extended to other metals or support.