Molecular Dynamics Simulations of the Coalescence of Iridium Clusters

Abstract

The coalescence of small iridium clusters was studied using a molecular dynamics (MD) technique with a cluster Sutton−Chen potential. MD simulations were carried out on the reaction of two clusters from 1 to 7 atoms at various incident angles and initial kinetic energies. The threshold energy of product formation was investigated for the various systems, and the effect of initial orientation between two clusters on the product was also studied. A comparison of diffusion and Ostwald-ripening coalescence mechanisms was performed for 8-atom cluster formation, and Ostwald-ripening led to cluster formation with higher initial energies. An atom-to-bond collision resulted in the formation of a larger cluster more often and at higher energies than an atom-to-atom collision.

Nature of Hydrogen Interaction and Saturation on Small Titanium Clusters

“…In the past, molecular dynamics simulations have been widely used to obtain the sticking probabilities of adsorbates on surfaces . More recently, they have been used to identify the evolution of various cluster structures and also to understand the dissociation mechanism of adsorbates on metal surfaces. , Although we have carried out a number of trajectories starting from several initial structures, we highlight the relative energies of one such trajectory of the Ti 4 H 2 system as a function of the simulation time in the upper panel of Figure . The reasons for highlighting this trajectory will be given shortly.…”

Molecular Dynamics Studies of the Coalescence of Silver Clusters

“…30 The outcome of Ag 4 + Ag 4 collision is different from that of Ir 4 + Ir 4 , where only coalescence products, i.e., Ir 8 , were formed within the same kinetic energy range. 68 This shows that the growth mechanism of different metal clusters is different.…”

Growth Kinetics of Nanoclusters in Solution

“…A crossover from an early time regime of coalescence-induced growth to an asymptotic Ostwald ripening regime has been observed in a Monte Carlo simulation 33 of coarsening in thin films. Pawluk and Wong 34 have used ab initio molecular dynamics simulations to show that the process of coalescence leads to the formation of low-energy iridium clusters, and the experimental studies of Tiemann et al 35 Figure 5. Scaling plot of correlation function [C(r, t) vs r/L] at different times.…”

“…A crossover from an early time regime of coalescence-induced growth to an asymptotic Ostwald ripening regime has been observed in a Monte Carlo simulation of coarsening in thin films. Pawluk and Wong have used ab initio molecular dynamics simulations to show that the process of coalescence leads to the formation of low-energy iridium clusters, and the experimental studies of Tiemann et al have emphasized the importance of coalescence processes in the growth of ZnS nanoparticles. Coalescence-induced growth may be distinguished from the reaction-controlled growth found in our study by either the value of the growth exponent or the shape of the droplet size distribution …”