Dresden 2014 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 37: Poster Session 2

CPP 37.45: Poster

Mittwoch, 2. April 2014, 15:00–19:00, P3

Stability limits of n-nonane calculated from MD-interface-simulations — •Stephan Braun¹, Attila Imre², and Thomas Kraska¹ — ¹University of Cologne, Institute of Physical Chemistry,Luxemburger Str. 116, D-50939 Köln — ²HAS Centre for Energy Research, H-1525 POB 49, Budapest

Based on molecular dynamics simulation of the vapor-liquid interface, the classical thermodynamic spinodal for n-nonane is estimated. The determination of the spinodal is based on properties of the liquid vapor interface. This method relates the tangential pressure component through the vapor*liquid interface to the van der Waals loop in the two-phase region of the phase diagram. By application of the thermodynamic stability criteria, the location of the spinodal can be determined. Up to now the applicability of this method was demonstrated for substances such as Lennard-Jones Argon, carbon dioxide or methanol but not for molecules with a highly anisotropic shape. The choice of n-nonane as investigated molecule originates from the question whether a deviation from the spherical symmetry of a molecule affects the prediction of the stability limit data. One might expect that anisotropic properties of the molecules influence the tangential pressure profile and hence the spinodal. As a result, we find that the estimated stability limit data for n-nonane are consistent within the experimental data available for the homologous series of the n-alkanes. It turns out that the slight alignment of the molecules parallel to the interface reported in the literature does not affect the method of transferring interface properties to the bulk phase stability limit.