Capillary Waves at Liquid/Vapor Interfaces: A Molecular Dynamics Simulation

Journal Article · Fri Jul 16 04:00:00 EDT 1999 · Physical Review E

DOI:https://doi.org/10.1103/PhysRevE.60.6708· OSTI ID:9474

Sides, Scott W ^[1]; Grest, Gary S; Lacasse, Martin-D

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1. Sandia National Laboratories

Evidence for capillary waves at a liquid/vapor interface are presented from extensive molecular dynamics simulations of a system containing up to 1.24 million Lennard-Jones particles. Careful measurements show that the total interfacial width depends logarithmically on L{sub {parallel}}, the length of the simulation cell parallel to the interface, as predicted theoretically. The strength of the divergence of the interfacial width on L{sub {parallel}} depends inversely on the surface tension {gamma}. This allows us to measure {gamma} two ways since {gamma} can also be obtained from the difference in the pressure parallel and perpendicular to the interface. These two independent measures of {gamma} agree provided that the interfacial order parameter profile is fit to an error function and not a hyperbolic tangent, as often assumed. We explore why these two common fitting functions give different results for {gamma}.

• Research Organization: Sandia National Labs., Albuquerque, NM (US); Sandia National Labs., Livermore, CA (US)
• Sponsoring Organization: US Department of Energy (US)
• DOE Contract Number: AC04-94AL85000
• OSTI ID: 9474
• Report Number(s): SAND99-1912J
• Journal Information: Physical Review E, Journal Name: Physical Review E
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
COMPUTERIZED SIMULATION
FLUID MECHANICS
INTERFACES
LENNARD-JONES POTENTIAL
LIQUIDS
MOLECULAR DYNAMICS METHOD
ORDER PARAMETERS
SURFACE TENSION
VAPORS