Melting behaviors of Co (N= 13, 14, 38, 55, 56) clusters

Investigation of Melting Dynamics of Hafnium Clusters

“…The melting data obtained via simulation can be used to study the dynamics of phase change. Comparisons between commonly used postprocessing methods are discussed by Lu et al The most commonly used postprocessing method is caloric curves, whereby the binding energy (or binding energy per atom) is plotted against temperature. Another route of measuring melting is through constant temperature specific heat capacity, c ν , as a function of temperature, which is actually the fluctuations of the caloric curve where E t is the total energy of the cluster, k B is the Boltzmann constant, n is the total number of atoms in the cluster, and ⟨⟩ T represents the thermal average at temperature T .…”

“…A typical c ν curve appears in the form of a sharp peak at the melting temperature, T m . Lu et al showed that there is a mismatch in the melting temperature of Co 13 and Co 14 clusters, if the Lindemann index, δ, is used as a means to gauge the melting process, as compared to the c ν curve. The Lindemann index is where r ij is the distance between the i th and j th atoms.…”

Effect of grain size on the melting point of confined thin aluminum films

“…78 This index is a simple but effective measure of thermally driven disorder and is often used to characterize the thermal evolution of systems. [79][80][81] In many cases, this parameter has proved advantageous over an order parameter 82 and potential energy. 83 For a system of N atoms, the local Lindemann index, d i , for the i-th atom in the system is defined as the rootmean-squared (rms) bond length fluctuation,…”

Molecular dynamical simulations of melting behaviors of metal clusters

“…Such lag phenomena are discussed in detail in our previous studies of the small cobalt clusters (Co 13 and Co 14 ). 21 For each cluster within the four specific sizes (13, 55, 147 and 309) of all elements investigated, the MD annealing simulation is performed from a relatively high temperature (ensure the cluster is in liquid-like state) to a relatively low temperature (ensure the cluster is in solid-like state), and the final structure (at the lowest temperature) is relaxed to a statically stable geometry as called the MD annealing structure. Generally the annealing structure is low-lying in energy (in some cases it is just the ground-state one, and this is indeed the case for the small-sized cluster).…”

“…For example, the investigation by Jarrold et al revealed that the reactivity of Al clusters can be enhanced through cluster melting; 19 Mottet et al found the melting points of Ag clusters can be changed by doping; 20 The correlations with structural changes are often investigated to explore the melting behaviors of metal clusters in detail. For example, the distinct isomerization transitions occurred prior to its full melting for a 38-atom Co cluster; 21 Schebarchov et al found there is a structural change from the icosahedron to the decahedron in liquid-solid co-existing Ni cluster; 22 Wen et al specifically studied the shape transformation of a tetrahedral Pt cluster during its melting. 23 As it is known, the fcc, bcc structures should be the favorable geometries for large aggregates and the icosahedral or decahedral structures can dominate the small clusters.…”