2026-10-13T11:48:19Z https://api.figshare.com/v2/oai

oai:figshare.com:article/33986766 2026-09-24T16:07:00Z category_1 category_4 category_915 category_7 category_16 category_873 category_734 category_133 portal_63 item_type_3 month_year_09_2026

Beyond the Virial Expansion: Microscopic Origins of Partial Molar Volumes in LiCl Solutions Chun-Ting Lin (1951819) Diganta Dasgupta (25104723) Tinglu Yang (820554) Cesare Malosso (22292029) Giulia Sormani (8157789) Colin Egan (14205776) Giovanni Bussi (1293816) Ali Hassanali (2343622) Paul S. Cremer (1306404) Biophysics Biochemistry Physical Sciences not elsewhere classified Medicine Physiology Chemical Sciences not elsewhere classified Biological Sciences not elsewhere classified Plant Biology sup >+</ sup modeling electrolyte solutions key thermodynamic properties including osmotic coefficients density functional theory accurate force fields treatment quantitatively reproduce partial molar volumes ion clustering emerges aqueous licl solutions partitioning molecular dynamics experimental pmv curve associated virial expansion individual salt ions resulting data enable derive pmv profiles virial expansion aqueous ions water volumes proper treatment pmv data ion pairs salt increases isolated ions water molecules water electrostriction water decreases volumetric interpretation simulation snapshots ring structures remained elusive raman spectroscopy procedures established order chain nonlocal interactions new generation microscopic origins level details general framework eutectic point direction reverses direct structural corresponding ionic clear progression calculations elucidate also persists Although electrolyte density measurements have been reported for over a century, employing them to determine accurate partial molar volume (PMV) profiles as a function of salt concentration has remained elusive. Obtaining such curves requires precise density measurements combined with a proper treatment of the associated virial expansion. In this work, we derive PMV profiles for aqueous LiCl solutions. The resulting data enable the development of highly accurate force fields for Li⁺ and Cl^–, revealing a clear progression from isolated ions to ion pairs and ultimately to higher-order chain and ring structures. Because ion clustering emerges from nonlocal interactions, it cannot be easily mapped onto specific virial terms. Instead, a direct structural and volumetric interpretation can be achieved by partitioning molecular dynamics (MD) simulation snapshots into three-dimensional polyhedral regions associated with individual salt ions and water molecules. The corresponding ionic and water volumes from this treatment quantitatively reproduce the experimental PMV curve, showing that the PMV for salt increases (while water decreases) up to 6.7 M. Above this concentration, the direction reverses as three- and four-body interactions become prominent. Complementary multivariate curve resolution (MCR) Raman spectroscopy and density functional theory (DFT) calculations elucidate the molecular-level details of water electrostriction, which also persists up to 6.7 M. Significantly, the PMV data can be correlated with key thermodynamic properties, including osmotic coefficients and the eutectic point. The procedures established here provide a general framework for modeling electrolyte solutions and enable the development of a new generation of accurate force fields for aqueous ions. 2026-09-24T00:00:00Z Dataset Dataset 10.1021/jacs.6c08519.s001 https://figshare.com/articles/dataset/Beyond_the_Virial_Expansion_Microscopic_Origins_of_Partial_Molar_Volumes_in_LiCl_Solutions/33986766 CC BY-NC 4.0