Nanometer-Scale Correlations in Aqueous Salt Solutions.

The intermediate-range (1-4 nm) correlation of cations, anions, and water in aqueous alkaline earth salt solutions is measured using synchrotron X-ray diffraction. We differentiate from the entire solution structure factor, (), a separate region at low (<1.5 Å) containing local diffraction maxima (prepeaks) that indicate nanometer-scale oscillatory behavior.

One-dimensional intergrowths in two-dimensional zeolite nanosheets and their effect on ultra-selective transport.

Zeolite MFI is a widely used catalyst and adsorbent that also holds promise as a thin-film membrane. The discovery of nanometre-thick two-dimensional (2D) MFI nanosheets has facilitated methods for thin-film zeolite fabrication that open new horizons for membrane science and engineering. However, the crystal structure of 2D-MFI nanosheets and their relationship to separation performance remain elusive.

First principles Monte Carlo simulations of unary and binary adsorption: CO, N, and HO in Mg-MOF-74.

Dative bonding of adsorbate molecules onto coordinatively-unsaturated metal sites in metal-organic frameworks can lead to unique adsorption selectivities. However, the distortion of the electron density during dative bonding poses a challenge for force-field-based simulations. Here, we report first principles Monte Carlo simulations with the PBE-D3 functional for the adsorption of CO2, N2, and H2O in Mg-MOF-74, and obtain accurate predictions of the unary isotherms without any of the adjustments or fitting often required for systems with strong adsorption sites.

Supersaturated calcium carbonate solutions are classical.

Mechanisms of CaCO nucleation from solutions that depend on multistage pathways and the existence of species far more complex than simple ions or ion pairs have recently been proposed. Herein, we provide a tightly coupled theoretical and experimental study on the pathways that precede the initial stages of CaCO nucleation. Starting from molecular simulations, we succeed in correctly predicting bulk thermodynamic quantities and experimental data, including equilibrium constants, titration curves, and detailed x-ray absorption spectra taken from the supersaturated CaCO solutions.

First-Principles Molecular Dynamics Study of a Deep Eutectic Solvent: Choline Chloride/Urea and Its Mixture with Water.

First-principles molecular dynamics simulations in the canonical ensemble at temperatures of 333 and 363 K and at the corresponding experimental densities are carried out to investigate the behavior of the 1:2 choline chloride/urea (reline) deep eutectic solvent and its equimolar mixture with water. Analysis of atom-atom radial and spatial distribution functions and of the H-bond network reveals the microheterogeneous structure of these complex liquid mixtures. In neat reline, the structure is governed by strong H-bonds of the trans- and cis-H atoms of urea to the chloride ion.