The Impact of the Temperature Control Strategy in Steady-State Virtual Vacuum Simulation on the Spontaneous Evaporation Rate and Corresponding Evaporation Coefficient

In the present paper, we propose a novel simulation approach that allows one to capture the steady-state evaporation into virtual vacuum state by maintaining a constant number of atoms within the liquid phase during the simulations. The proposed method was used to perform virtual vacuum simulations of argon at a temperature of 90 K in order to study the effects of the chosen simulation temperature control approach on the system’s temperature profiles, spontaneous evaporation rates, and the energetic characteristics of the evaporating atoms. The results show that the expected non-uniform temperature profile across the liquid phase can be flattened out by dividing the liquid phase into separately thermostated bins. However, the desired liquid surface temperature can be achieved only when the thermostat region boundary is placed outside the liquid phase. The obtained relationship between the surface temperature and the spontaneous evaporation rate show that the spontaneous evaporation rate and corresponding evaporation coefficient evaluation may change up to 21% when the surface temperature changes in a narrow temperature interval of 2.45 K. Furthermore, the results demonstrate that the thermostat region boundary position has no impact on the energetic characteristics of the evaporating argon atoms, even when the boundary is placed outside the liquid phase.