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Computational Approaches to Polymeric Nanocomposites
Published in Sefiu Adekunle Bello, Hybrid Polymeric Nanocomposites from Agricultural Waste, 2023
Saheed Olalekan Ojo, Sikiru Oluwarotimi Ismail
In a case where molecular interaction is involved, a pair potential is not sufficient to capture the particle interaction, since molecules are characterised by covalent bonds [2]. In this case, apart from energy change due to change of bond length (Ebond), force field contributions arising from energy changes associated with a change in the bond angle (Eangle), molecular rotations (Etorsion), out-of-plane interactions between molecules (Eoop), other types of interaction energies (Enonbond), or cross terms between other interaction terms (Ecross) may be significant. Therefore, the total energy of a molecule is expressed as Equation (5.36) [2]. E=Ebond+Eangle+Etorsion+Eoop+Enonbond+Ecross
Macro- and Microcomputational Materials Mechanics
Published in Yichun Zhou, Li Yang, Yongli Huang, Micro- and MacroMechanical Properties of Materials, 2013
Yichun Zhou, Li Yang, Yongli Huang
In the early stage of molecular dynamics simulation, the pair potential is often adopted. In the pair potential, atomic interaction is constricted to two atoms, and is not related to other particles. Therefore, when calculating the interaction between two atoms, the influence of other particles is not considered. This is a relatively good approximation in some cases. The potential of particle i in the system is () Ui=12∑jurij.
Free energy and concentration of crystalline vacancies by molecular simulation
Published in Molecular Physics, 2018
Apoorva Purohit, Andrew J. Schultz, Sabry G. Moustafa, Jeffrey R. Errington, David A. Kofke
We employed the Lennard–Jones (LJ) model defined by the pair potential: , where and are the LJ size and energy parameters, respectively, and r is the pair separation. The LJ potential was truncated and shifted at , and and parameters were set to unity (LJ units). The system energy was corrected by adding the difference in lattice energies with and without the shift (equal to number of interacting lattice neighbours multiplied by the shift), but this correction was adjusted when vacancies were present. With n vacancies, the correction was taken to be . Periodic boundary conditions were employed in all three orthogonal directions.