A nonequilibrium molecular dynamics simulation of evaporation

The net evaporation process is investigated by performing non-equilibrium molecular dynamics simulations. The transient density, temperature and pressure profiles are statistical calculated, and the net evaporation flux is obtained from molecular level. With Hertz-Knudsen- Labuntsov equation, the evaporation coefficients based on nonequilibrium molecular dynamics simulations are computed and compared with the data calculated by the equilibrium molecular dynamics simulations and the transition state theory. The evaporation coefficients of the nonequilibrium molecular dynamics agree with those from the transition state theory and some data of equilibrium molecular dynamics calculations in literature within 15%. However, if using Hertz-Knudsen-Labuntsov equation to predict the net evaporation/condensation mass flux, the statistical model presented by Matsumoto et al., (1995) does not show reasonable agreement with present simulation and some other data in literature, especially in the high temperature region.