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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 21: Crystallization, Nucleation and Self-Assembly

CPP 21.4: Vortrag

Montag, 16. März 2020, 15:45–16:00, ZEU 255

Ordering of small polymer systems through the prism of partition function zeros. — •Timur Shakirov and Wolfgang Paul — Institute of Physics, University of Halle, Halle, Germany

Typical low temperature conformations of small alkane systems (single chains and few chain aggregates) differ frequently from the melt ones: even relatively short chains are folded in non-trivial structures at low temperatures [1]. The ordering of a system is related to change of thermodynamic and conformational characteristics of chains. In the case of big systems, the changes occur at one the same transition temperature, whereas for small systems the typical temperatures of the changes can be shifted relative to each other. The sensitivity of thermodynamic functions to the shift differs and can be hidden because of a widening of the transition region of the small system. We present here the results of an analysis of the partition function zeros, which helps to identify a two stage conformational reorganization of small alkane systems. Our calculations are based on Wang-Landau-type Monte Carlo simulations [2,3] of a chemically realistic united atom model [4].

[1] T. Shakirov, and W. Paul, J. Chem. Phys. 2019, 150, 084903.

[2] F. Liang, C. Liu, R. J Carroll, J. Am. Stat. Assoc. 2007, 102, 305-320.

[3] T. Shakirov, Comp. Phys. Commun. 228 (2018), 38-43.

[4] W. Paul, D. Y. Yoon, and G. D. Smith, J. Chem. Phys. 103 (1995) 1702-1709.