We have performed a series of neutron scattering experiments on supercritical krypton. Our data and analysis allow us to characterize the Frenkel line crossover in this model monatomic fluid. The data from our measurements was analyzed using Empirical Potential Structure Refinement to determine the short- and medium-range structure of the fluids. We find evidence for several shells of neighbors which form approximately concentric rings of density about each atom. The ratio of second to first shell radius is significantly larger than in any crystal structure. Modeling krypton using a Lennard-Jones potential is shown to give significant errors, notably that the liquid is overstructured. The true potential appears to be longer ranged and with a softer core than the 6-12 powerlaws permit.
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http://dx.doi.org/10.1021/acs.jpclett.2c02004 | DOI Listing |
Langmuir
January 2025
Thermodynamik, Technische Universität Berlin, 10587 Berlin, Germany.
The binary collision of nanoscale droplets is studied with molecular dynamics simulation for droplets consisting of up to 2 × 10 molecules interacting via a truncated and shifted form of the Lennard-Jones potential. Considering head-on collisions of droplets with a temperature near the triple point that occur in a saturated vapor of the same fluid, this work explores a range of collision topologies. Four droplet sizes, with a radius ranging from 30 to 120 molecule diameters, are simulated with a varying initial relative collision velocity, covering 36 cases in total.
View Article and Find Full Text PDFJ Mol Model
January 2025
School of Semiconductors and Physics, North University of China, Xueyuan Road #3, 030051, Taiyuan, China.
Context: Based on the transition state theory, a molecular diffusion model in the narrow channels of Brewsterite zeolite was established. In this model, the molecular interaction at the potential barrier was simplified to only consider the repulsive potential, so that the analytical relationship between the diffusion coefficient and the temperature and the Lennard-Jones interaction parameter was derived. We used the molecular dynamics method to simulate the diffusion of four molecules, CF, CH, Ar, and Ne, in Brewsterite zeolite and evaluated the rationality of the model.
View Article and Find Full Text PDFJ Chem Phys
December 2024
Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Amsterdam, The Netherlands.
In simulations, particles are traditionally treated as rigid platforms with variable sizes, shapes, and interaction parameters. While this representation is applicable for rigid core platforms, particles consisting of soft platforms (e.g.
View Article and Find Full Text PDFJ Phys Chem B
January 2025
Saint Joseph's University, 600 S. 43rd Street, Philadelphia, Pennsylvania 19104, United States.
Molecular dynamics simulations are a powerful tool for probing and understanding the theoretical aspects of chemical systems and solutions. Our research introduces a novel method for determining the excess chemical potential of non-ideal solutions by leveraging the equivalence between the chemical potential of the vapor phase and liquid phase. Traditional approaches have relied on bulk simulations and the integration of pair distribution functions (()), which are computationally intensive to obtain accurate results.
View Article and Find Full Text PDFActa Crystallogr A Found Adv
January 2025
Department of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom.
FFLUX is a multipolar machine-learned force field that uses Gaussian process regression models trained on data from quantum chemical topology calculations. It offers an efficient way of predicting both lattice and free energies of polymorphs, allowing their stability to be assessed at finite temperatures. Here the Ih, II and XV phases of ice are studied, building on previous work on formamide crystals and liquid water.
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