where h is a matrix composed of a, b and c. To model molecular systems, Nosé and Klein incorporated long-range charge-charge interactions, and improved the previous methods by adding a constraint to prevent unnecessary rotation of the MD cell. This method was later advanced by Hoover, and it is commonly referred to as the Nosé-Hoover barostat. Subsequently, Wentzcovitch expanded the scope of the PR approach by making it invariant with respect to the choice of simulation cell. Berendsen et al. introduced a distinct category of barostats, where an external bath with constant pressure is coupled to a system by incorporating an additional pressure term into the equations of motion,