Structure diagram of binary Lennard-Jones clusters

Abstract

We analyze the structure diagram for binary clusters of Lennard-Jones particles by means of a global optimization approach for a large range of cluster sizes, compositions and interaction energies and present a publicly accessible database of 180,000 minimal energy structures (http://softmattertheory.lu/clusters.html). We identify a variety of structures such as core-shell clusters, Janus clusters and clusters in which the minority species is located at the vertices of icosahedra. Such clusters can be synthesized from nanoparticles in agglomeration experiments and used as building blocks in colloidal molecules or crystals. We discuss the factors that determine the formation of clusters with specific structures.

Partitioning of polycyclic aromatic hydrocarbons in heterogeneous clusters

“…LJ clusters made up of two different sized particles with the same interaction potential are known to configure in a core-shell structure, with larger particles on the surface and smaller particles in the core, in order to equalise surface and bulk interactions [65,64,66,67]. In contrast, LJ clusters containing two particle types of the same size but different attractions partition in the opposite core-shell structure, in which the more strongly attractive particles make up the core and the more weakly attractive particles compose the shell [63]. Heterogeneous PAH clusters show a structure similar to the latter case, suggesting that the strength of intermolecular interactions plays a more dominant role in determining cluster structure than the molecular size differences.…”

On the phase diagram of Mackay icosahedra

“…by DNA-based ligands [38] or the inclusion of magnetic sub-particles [39]. This would enable us to simulate the assembly of the patchy building blocks in the form of binary icosahedral clusters with symmetric or Janus arrangements of interacting sites on the surface of clusters, which have been predicted before [10].…”

“…This quasi-spherical arrangement is a particularly stable motif in the minimal energy Lennard-Jones diagrams for binary systems of particles in a wide range of different attraction ratios. The coordinates of sub-particles were obtained from a database of minimal energy Lennard-Jones clusters [10]. In our simulations we define an icosahedral molecule as a rigid arrangement of the 42 sub-particles from the outer shell of the energy-minimized Mackay icosahedron.…”

“…Confinement of spherical gold nanoparticles inside spherical surfaces of emulsion droplets leads to an assembly of nanocrystals with superlattices corresponding to Mackay icosahedra [8]. The structures of these clusters keep the polyhedral character also for binary mixtures of particles with different attractions [10] while differences in atmospheric pressure can determine the formation of either a complex binary crystal super-lattice, core-shell, or Janus clusters in dispersions of nanoparticle with binary size distributions [11]. Mackay icosahedra have also been ob- Figure 1.…”

Alloy, Janus and core–shell nanoparticles: numerical modeling of their nucleation and growth in physical synthesis

“…The two first species are reactive, and their interactions are tailored to obtain (1) alloy, (2) Janus and (3) core-shell NPs [See Table I]. In the two latter cases, the coefficients are chosen by following the work of Mravlak et al who computed the most stable structures of binary nanoclusters for a large number of combination of coefficients [79]. In the alloy case, the σ parameters are chosen to obtain the Kobb-Andersen system, which crystallizes in alloy BCC structures [80][81][82][83], while the energy parameters are set in a way to roughly match the melting and boiling temperatures obtained with the core-shell and Janus systems.…”