New Coarse-Grained Model and Its Implementation in Simulations of Graphene Assemblies

Abstract

Graphene is a one-atom thick layer of carbon atoms arranged in a hexagonal pattern, which makes it the strongest material in the world. The Tersoff potential is a suitable potential for simulating the mechanical behavior of the complex covalently bonded system of graphene. In this paper, we describe a new coarse-grained (CG) potential, TersoffCG, which is based on the function form of the Tersoff potential. The TersoffCG applies to a CG model of graphene that uses the same hexagonal pattern as the atomistic model. The parameters of the TersoffCG potential are determined using structural feature and potential-energy fitting between the CG model and the atomic model. The modeling process of graphene is highly simplified using the present CG model as it avoids the necessity to define bonds/angles/dihedrals connectivity. What is more, the present CG model provides a new perspective of coarse-graining scheme for crystal structures of nanomaterials. The structural changes and mechanical properties of multilayer graphene were calculated using the new potential. Furthermore, a CG model of a graphene aerogel was built in a specific form of assembly. The chemical bonding in the joints of graphene-aerogel forms automatically during the energy relaxation process. The compressive and recover test of the graphene aerogel was reproduced to study its high elasticity. Our computational examples show that the TersoffCG potential can be used for simulations of graphene and its assemblies, which have many applications in areas of environmental protection, aerospace engineering, and others.

Collapsed carbon nanotubes: From nano to mesoscale via density functional theory-based tight-binding objective molecular modeling

“…The dog-bone shape of the collapsed CNTs, Figure 1(a)-(b), is the outcome of the balance between the bending energy stored at the closed edges and the van der Waals (vdW) energy gained by bringing in close contact of the flattened CNT walls [9,10]. In the quest of developing a mesoscale representation, one possibility is to pursue the CG of each one-atom thick graphene wall using the Martini force-field [11] or a Tersoff bond-order potential [12,13]. Such CG would capture the transformation from cylindrical to collapsed CNTs and therefore would be clearly needed if one would like to simulate the CNT stretching process [3,4].…”

On deformation of carbon nanotubes with TersoffCG: a case study

“…The unit cell sides were fixed to 6 nm along the directions perpendicular to the nanotube axis. We used for TersoffCG [13], Tersoff [14,15] and AIREBO [16] potentials the standard parametrizations, without taking into account typical internal cutoff for the near fracture regimes [17]. This, anyway have no influence on the results presented here.…”

“…However, each time we use a coarse grain model, we lose some information on the system with respect to the full atomistic description. In this work we evaluate the influence of using a recently developed a coarse grain potential for graphene [13], based on Tersoff potential, named Ter-soffCG, on the case study of a single wall carbon nanotube. We computed the stress strain curves under tension and compression along longitudinal direction, comparing the coarse grain model and two full atomistic models described by means of Tersoff [14,15] and AIREBO [16] potential.…”

Monte Carlo simulations of n-butane and n-octane adsorbed onto graphite and a molecular model of activated carbon

“…Recently several approaches called "coarse grain" (CG) have been developed with that goal in mind. The philosophy of these CG approaches is generally the same: to achieve a simpler description of the effective interactions in a given system without losing the ability of the resulting models to predict the properties of interest (Chiu et al 2010;Shelley et al 2001;Maerzke and Siepmann 2001;Mognetti et al 2009;Gobbo et al 2013;Shang et al 2017;Jiang et al 2017).…”