Global Structure Optimization of Pt Clusters Based on the Modified Empirical Potentials, Calibrated using Density Functional Theory

The geometry of platinum clusters Pt-n (n = 2-10, 13, 19, 24, 38, 55, and 75) was optimized at the UBLYP/CRENBS, UBPW91/CRENBS, UBPW91/LANL2DZ, and UPBE0/LANL08 density functional theory (DFT) levels for different spin states in order to establish their structure and thermodynamic properties and obtain reference data for the calibration of interatomic potentials. The optimized cluster structures and energies were used to elaborate the atomic parameters of the empirical potentials of Gupta and Sutton-Chen, and modified versions of these potentials SCG5 and SCGSA were developed for better description of medium range interactions. The new DFT-calibrated potentials were used for the global optimization of the cluster structure in the broad nuclearity range of n = 3-150 using the modified methods of artificial bee colony and Metropolis Monte Carlo simulated annealing. The structures obtained during the global optimization with modified potentials show a much higher tendency to form decahedral and face-centered cubic structures at lower n instead of icosahedral ones found with classical metallic potentials.