Phase-field modelling of molecular dynamics with diffusive motions

Recently, phase-field modelling has been expanded to the molecular scale. However, such atomistic phase-field simulation cannot treat diffusive motions of molecules so far. Here, we modify phase-field modelling of molecular dynamics to include rigid body motions by employing quaternions and smooth random functions. This modelling successfully reproduces translational and rotational diffusive motions of a molecule. This study further expands the applications of atomic-scale phase-field modelling.