Ir nanocluster shape effects on melting, surface energy and scaling behavior of self-diffusion coefficient near melting temperature

Abstract

Shape effect on Metallic Nano particles has many applications in technology, engineering and industry. Molecular dynamic simulations have been performed to investigate size and shape effects of Iridium nanocluster on its surface energy (Esur) and self-diffusion coefficient (D) as a function of temperature (T). Truncated octahedron (TO), octahedron (Oh), cubic (C), and face center cubic (FCC) of Iridium nanocluster were studied in this survey. At temperatures lower than 1000 K, Esur order is as follows: TO > C > Oh > FCC while at temperatures higher than 1000 K it has a different order as TO > Oh > C > FCC. Self-diffusion coefficient increases versus temperatures as expected, but results show that it is roughly the same for all systems at T < 1800 K and T greater than 2500. At temperature range T (1800, 2500), self-diffusion coefficient order is as follows: TO ≈ Oh ≈ C < FCC. TO≅Oh≅C<FCCInterestingly, DFCC is smaller than D for other shapes of Iridium nanocluster. Self-diffusion coefficient as a function of nanocluster size was calculated with molecular dynamics simulation. It is shown there is a peak for D at N = number of particles = 700 which corresponds to surface effect. MD results show that FCC has more solid like long-range interaction, but others have more liquid like order.