Regensburg 2010 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 28: Phase transitions and Critical Phenomena II
DY 28.6: Vortrag
Donnerstag, 25. März 2010, 15:30–15:45, H47
First-order-like Behavior at the Adsorption Transition of Short Polymers in the Microcanonical Ensemble — •Monika Möddel1, Wolfhard Janke1, and Michael Bachmann2 — 1Institut für Theoretische Physik, Universität Leipzig — 2Institut für Festkörperforschung, Theorie II, Forschungszentrum Jülich
The understanding of the cooperative effects of structure formations at substrates requires systematic studies of mesoscopic aspects. We perform such a study focusing on the adsorption transition [1,2]. This is conveniently and to our knowledge for the first time done by a detailed microcanonical analysis [2] of densities of states obtained by extensive multicanonical Monte Carlo computer simulations.
For short chains and strong surface attraction, the microcanonical entropy turns out to be a convex function of energy in the transition regime, indicating that surface-entropic effects are relevant. Albeit known to be a continuous transition in the thermodynamic limit of infinitely long chains, the adsorption transition of polymers with finite length thus exhibits a clear signature of a first-order-like transition, with coexisting phases of adsorbed and desorbed conformations.
[1] M. Möddel, M. Bachmann, and W. Janke, J. Phys. Chem. B 113, 3314 (2009).
[2] M. Möddel, M. Bachmann, and W. Janke, preprint.