Effects of simulation system on the phase transition behavior of liquid film: A molecular dynamics study

In the present study, the effects of liquid film thickness and simulation box geometry on the molecular dynamics simulation studies of phase transition are investigated. Results show that the simulation system has significant impacts on phase transition behaviors of the liquid film because of the applications of periodic boundary and reflecting boundary. The evaporation and bubble nucleation phenomena happen on the substrate with a temperature of 140 K. If the heated liquid film is thin or the height of the simulation box is low, the evaporated liquid atoms from the interface of vapor-liquid cause a high vapor pressure and prevent the happening of bubble nucleation in the vicinity of the substrate, and only evaporation phenomenon happens. When the substrate temperature is raised to 150 K, a bubble nucleus turns up on the substrate. If the length of the simulation box is short, the bubble nucleus converts into a vapor film quickly under the joint effects of liquid film lifting and high-temperature liquid vaporization, and the explosive boiling phenomenon happens. However, with the increase of the length of the simulation box, a distinct bubble nucleation and growth process are observed. The present study can provide a reference for researchers in the molecular dynamics simulation studies of phase transition.