  A new phase field crystal (PFC) type theory is presented, which accounts for
the full spectrum of solid-liquid-vapor phase transitions within the framework
of a single density order parameter. Its equilibrium properties show the most
quantitative features to date in PFC modelling of pure substances, and full
consistency with thermodynamics in pressure-volume-temperature space is
demonstrated. A method to control either the volume or the pressure of the
system is also introduced. Non-equilibrium simulations show that 2 and 3-phase
growth of solid, vapor and liquid can be achieved, while our formalism also
allows for a full range of pressure-induced transformations. This model opens
up a new window for the study of pressure driven interactions of condensed
phases with vapor, an experimentally relevant paradigm previously missing from
phase field crystal theories.
