Pressure tensor for electrostatic interaction calculated by fast multipole method with periodic boundary condition.

A microscopic expression of the pressure tensor using the fast multipole method (FMM) with periodic boundary conditions has been derived. The pressure tensor calculated using this expression has been compared with that obtained using the Ewald method with high accuracy. The precision of the pressure tensor can be controlled as a function of expansion order p of FMM. Using the calculated pressure tensor, the constant pressure molecular dynamics calculation with fully fluctuating cell can be performed for anisotropic systems such as crystals, metals, liquid crystals, glasses, polymers, lipid bilayers, and interfacial regions between two phases. © 2018 Wiley Periodicals, Inc.