Naslov
Local entropy/energy fluctuations in molecular liquids: the role of the site- site bridge function

Autori
Lovrinčević, Bernarda

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
New frontiers in liquid matter / - , 2022, 50-51

Skup
CECAM Workshop: New Frontiers in Liquid Matter

Mjesto i datum
Pariz, Francuska, 04.07.2022. - 07.07.2022

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Liquids ; fluctuations ; correlation function ; integral equation theory

Sažetak
The description of liquids through pair correlations requires to include higher order correlations through the so-called bridge function [1, 2]. This contribution can be considered as accounting for fluctuations as seen from pair level description. Neglecting these contributions reduces the pair level description to mean field type. For simple liquids and their mixtures, atomic or molecular, it is found that these bridge contributions are rather small [3, 4]. For complex liquids, however, the comparison between exact pair correlations (as obtained from simulations) and approximate ones where the bridge is neglected, is often catastrophic [5, 6, 7, 8]. This is particularly true for mixtures, for which it is often impossible to obtain numerical solutions [9, 10, 11]. The bridge function can be calculated from simulations, both for the molecular [12] and atom-atom versions [8] of the integral equation theory (IET), thus making both approaches exact. In order to better interpret the meaning of the bridge function, we consider that the fluctuations depend on local energy and entropy. This separation allows to intuitively understand the importance of the bridge function in the atom-atom IET: since molecules are represented in atomic details, the energy contribution of the corresponding fluctuations are directly provided into the theory as intra- molecular correlations, without the compensation of the entropy contributions. This does not hold for the molecular theory, where the intra-molecular correlations are not taken into account, leading to a compensation which explains why it has qualitatively better predictions than the atom-atom version. In other words, the need for the bridge function is more important in the atom-atom version of IET. We test and illustrate this hypothesis in the case of model molecular systems, by tuning the local ordering as to enhance or restrict the corresponding local fluctuations through clustering. [1] J. P. Hansen, I. R. McDonald, Theory of Simple Liquids, Academic, London (1986). [2] J. Barrat, J. Hansen, G. Pastore, Molecular Physics, 63, 747-767 (1988) [3] J. Kolafa, S. Labik, A. Malijevsky, Molecular Physics, 100, 2629-2640 (2002) [4] E. Lomba, M. Alvarez, G. Stell, J. Anta, The Journal of Chemical Physics, 97, 4349-4355 (1992) [5] L. Lue, D. Blankschtein, The Journal of Chemical Physics, 102, 5427-5437 (1995) [6] B. Pettitt, P. Rossky, The Journal of Chemical Physics, 77, 1451-1457 (1982) [7] G. Reddy, C. Lawrence, J. Skinner, A. Yethiraj, The Journal of Chemical Physics, 119, 13012-13016 (2003) [8] B. Kežić, A. Perera, The Journal of Chemical Physics, 135, 234104 (2011) [9] H. Tanaka, J. Walsh, K. Gubbins, Molecular Physics, 76, 1221-1233 (1992) [10] K. Yoshida, T. Yamaguchi, A. Kovalenko, F. Hirata, J. Phys. Chem. B, 106, 5042-5049 (2002) [11] A. Perera, B. Kežić, Faraday Discuss., 167, 145 (2013) [12] L. Belloni, The Journal of Chemical Physics, 147, 164121 (2017)

Izvorni jezik
Engleski

Znanstvena područja
Fizika, Kemija

POVEZANOST RADA