Cavity formation in the superheated Lennard-Jones liquid and its connection to homogeneous bubble nucleation:A density-functional theory study

摘要

Recent Monte Carlo simulation studieds of a model superheated liquid [Punnathanam and Corti,Ind.Eng.Chem.Res.41,1113(2002)] suggest that cavity formation plays an important role in the process of homogeneous bublle nucleation.These simulations revealed that when speherical cavities,and the critical cacity in particular,to the moleculr mechanims of homogeneous bubble nucleation.Density-functional theory(DFT) calculations are used to verify the existence of the critical cavity within the superheated Lennard0Jones liquid.In addition,DFT reveals that the critical cavity represents a limit of thermodynamic stability,further strengthening the connection between cavities and bubble nucleation.The DFT calculations also show that the size of the critiacal cavity is a tight upper bound to the work of formation of the critical bubble.These results suggest that the free energy surface of bubble nucleation is influenced by the properties of the critical cavity,thereby possibly leading to a new picture of the molecular mechanism of bubble formation in superheated liquids.