NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Adsorption and solvation of ethanol at the water liquid-vapor interface: a molecular dynamics studyThe free energy profiles of methanol and ethanol at the water liquid-vapor interface at 310K were calculated using molecular dynamics computer simulations. Both alcohols exhibit a pronounced free energy minimum at the interface and, therefore, have positive adsorption at this interface. The surface excess was computed from the Gibbs adsorption isotherm and was found to be in good agreement with experimental results. Neither compound exhibits a free energy barrier between the bulk and the surface adsorbed state. Scattering calculations of ethanol molecules from a gas phase thermal distribution indicate that the mass accommodation coefficient is 0.98, and the molecules become thermalized within 10 ps of striking the interface. It was determined that the formation of the solvation structure around the ethanol molecule at the interface is not the rate-determining step in its uptake into water droplets. The motion of an ethanol molecule in a water lamella was followed for 30 ns. The time evolution of the probability distribution of finding an ethanol molecule that was initially located at the interface is very well described by the diffusion equation on the free energy surface.
Document ID
20040089403
Acquisition Source
Ames Research Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Wilson, M. A.
(NASA Ames Research Center Moffett Field CA United States)
Pohorille, A.
Date Acquired
August 21, 2013
Publication Date
April 17, 1997
Publication Information
Publication: The journal of physical chemistry. B, Materials, surfaces, interfaces & biophysical
Volume: 101
Issue: 16
ISSN: 1089-5647
Subject Category
Exobiology
Funding Number(s)
CONTRACT_GRANT: GM47818-01
CONTRACT_GRANT: NCC2-772
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Exobiology
NASA Center ARC

Available Downloads

There are no available downloads for this record.
No Preview Available