Approaches for Controlling the Temperature and Pressure Range in Generalized NPT Ensembles

Isobaric-multithermal and multibaric-isothermal methods are powerful methods for sampling in a wide energy and/or volume space. A finite temperature or pressure is required to study phase diagrams and many properties of many types of systems. However, it is difficult to control the temperature or pressure range because these systems move randomly in energy or volume space. Here, we develop a method to control the temperature range in the isobaric-multithermal ensemble and a method to control the pressure range in the multibaric-isothermal ensemble. These methods have the advantage of adequately determining the weight factor to create the multicanonical ensemble and can be applied to study thermodynamic properties.