Investigation of quantum effect of liquid hydrogen on homogeneous bubble nucleation using a density functional theory and molecular dynamics simulations

In this paper, a quantum effect of hydrogen molecules (uncertainties of each atomic nuclear position and momentum) on the bubble nucleation rate was investigated. The homogeneous bubble nucleation analyses were performed using a density functional theory (DFT) reflecting equations of state (EOSs) constructed to reproduce the thermophysical properties of hydrogen obtained from a classical molecular dynamics (MD) method and a quantum MD method. The results showed that the quantum nature of liquid hydrogen decreases the bubble nucleation rate when compared in the same reduced temperature and reduced superheat ratio condition. Further, it was indicated that the results might be caused by the increase of the energy barrier arising from the difference of the density profile and its position at the critical bubble (in other words, the differences of the critical bubble size and the liquid–vapor interface thickness). Furthermore, the DFT analysis was validated through the evaluation of the bubble nucleation rate using the classical MD method and the quantum MD method made as numerical experiments, and qualitatively the same result was obtained between the DFT and the MD simulations.