Unraveling a Thermodynamic Ensemble at the Quasicontinuum Scale: Interplay of van der Waals Forces without All the Atoms

Abstract We present a multiscale model capable of preserving microcanonical ensemble in van der Waals interaction that is consistent with Molecular Dynamics (MD) results. Our multiscale model has a Lagrangian -based framework with both energy and force-based descriptions embedded in continuum-atomistic and their bridging domain. Forces on the bridging/continuum interface are weighted from a dynamic residual basis to ensure easy kinetic transition from atomistic to continuum domains. A fracture study with a microcanonical ensemble explains the conservation of deformation, partition functions and stability with respect to the deformation gradient. Here, the two-length-scale study correctly calculates the critical tensile conditions, position and velocity distribution. Comparing the multiscale model with MD, the case studies showed a remarkable computational efficiency with only 8-12% of MD’s computational cost.