SKM 2023 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 6: Statistical Physics: General I

DY 6.9: Vortrag

Montag, 27. März 2023, 12:15–12:30, ZEU 160

Integral Equations in Statistical Mechanics: A Size-effect Study — •Jose Mauricio Sevilla Moreno and Robinson Cortes-Huerto — Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany

Integral equations (IE) are in the core of statistical mechanics of liquids as they connect the local structure with thermodynamic properties as compressibility, activity coefficients and excess entropy. IE are normally defined in the grand canonical ensemble and calculated in the thermodynamic limit (TL). By contrast, computer simulations are performed with finite-size systems and mimic the TL using periodic boundary conditions (PBC). This proceeding introduces several finite-size contributions whose effects must be identified and corrected in order to approximate the simulation results to the TL. In this talk, we present a generic method to compute IE from molecular dynamics simulations. In our approach, we define finite-size IE, integrating them in Fourier space to trivially introduce PBC. This procedure allows us to identify and isolate ensemble, finite-volume domains and PBC effects and accurately obtain the corresponding thermodynamic quantities in the TL or artificially for any finite size system. To validate our method, we compute isothermal compressibilities, chemical potentials and excess entropies of simple liquids and liquid mixtures, including water and aqueous alcohol solutions, showing good agreement with results available in the literature.