Group name: Group for molecular liquids
Short name: Molecular liquids group
Research area: Condensed matter physics
Group leader: Bernarda Lovrinčević
Project name: Dynamics in micro-segregated systems, HRZZ-UIP-2017-05-1863
Theme #1: General dynamical description of how molecules form objects such as micelles in water environment
Complex mixtures, such as aqueous mixtures, have a very particular structure that stems from the specific type of interactions, namely the hydrophobic and the hydrophilic interaction. This results in micro-segregation of molecules which in some systems leads to the creation of new objects, such as micelles or domains. This type of spatial organisation has been found even in non-aqueous systems, like ionic liquids or alcohol-alkane mixtures, which has been proved both by experiments and simulations. However, the information about the dynamics of these newly formed structures are rather scarce, especially in the field of molecular dynamics simulations, where the results strongly depend on the computational resources. We aim at understanding the lifetime of newly formed objects and their kinetics, which is a problem that lies at the heart of biophysics and material science.
Theme #2: Advance the understanding of dynamical processes in micro-segregated systems by using computer simulations and theoretical methods and to relate the results with the available experiment
Molecular dynamics simulations and theoretical approaches ensure solutions where experimental evidence becomes questionable. Transport properties, such as diffusion constants, viscosity and thermal conductivity, are of particular interest, since they affect most of the chemical processes. Autocorrelation functions, such as the velocity-velocity autocorrelation function give useful description about the dynamics in the liquid system. Simulations have shown to be quite useful in the calculation of the transport properties and autocorrelation functions in the recent studies of both aqueous and non-aqueous mixtures. Another great advantage of simulations is that they can enable the calculation of both static and dynamic properties of the system, giving at the same time deep insight on the microscopic level. This is particularly valuable in the study of biologically relevant systems and water mediated processes, such as the hydrophobic effect. In the past, there have been many studies focusing on the simplest systems governed by the hydrophobic effect – aqueous mixtures. Both simulation and experimental studies have confirmed micro-segregation of the constituent molecules and the existence of water domains. However, the time evolution of these domains is not fully understood.
Theme #3: Develop the dynamical density functional theory and its application to models and realistic systems.”
Application of dynamic theory to realistic liquids has been mostly limited to simple liquids, typically Lennard-Jones liquids, but also weakly polar liquids. In this perspective, it is important to understand that the extension of these approaches to associating liquids does not consist simply of accounting for yet another type of interaction – the associating interactions, but it would rather consist of taking into account the new physical phenomena that result from this interaction, namely micro-segregation. In order to better appreciate this point, it is noteworthy to recall that the hydrogen bonding of water under cooling undergoes a dramatic change in the local clustering. Obviously, this exceptional plasticity of water needs to be either described as a consequence of the type of interactions (hydrogen bonding), or to be directly incorporated into the theory. It is this dual aspect which motivates our desire for a new approach of dynamics.
– Aurélien Perera, researcher, Laboratory for theoretical physics of condensed matter, Sorbonne University, Paris, France
– László Almásy, researcher, Wigner Research Centre for Physics, Budapest, Hungary
- Lovrinčević, Bernarda; Bella, Adrien; Le Tenoux-Rachidi, Isham; Požar, Martina; Sokolić, Franjo; Perera, Aurélien, Methanol-ethanol “ideal” mixtures as a test ground for the computation of Kirkwood-Buff integrals // Journal of Molecular Liquids, 293 (2019), 111447-111456, https://doi.org/10.1016/j.molliq.2019.111447;
- Lovrinčević, Bernarda; Požar, Martina, Balić, Marijana, Dynamics of urea-water mixtures studied by molecular dynamics simulation // Journal of Molecular Liquids, 300 (2019) 112268, https://doi.org/10.1016/j.molliq.2019.112268;
- Almásy, László; Kuklin, Alexander I.; Požar, Martina; Baptista, Anthony; Perera, Aurélien, Microscopic origin of the scattering pre-peak in aqueous propylamine mixtures: X-ray and neutron experiments versus simulations // Physical Chemistry Chemical Physics, 21 (2019), 18; 9317-9325, https://pubs.rsc.org/en/content/articlehtml/2019/cp/c9cp01137d
Bernarda Lovrinčević, group leader
University of Split, Faculty of Science, Ruđera Boškovića 33, HR-21000 Split, Croatia
+385 21 619 245