92 research outputs found
Quasi-chemical theory with a soft cutoff
In view of the wide success of molecular quasi-chemical theory of liquids,
this paper develops the soft-cutoff version of that theory. This development
has important practical consequences in the common cases that the packing
contribution dominates the solvation free energy of realistically-modeled
molecules because treatment of hard-core interactions usually requires special
purpose simulation methods. In contrast, treatment of smooth repulsive
interactions is typically straightforward on the basis of widely available
software. This development also shows how fluids composed of molecules with
smooth repulsive interactions can be treated analogously to the molecular-field
theory of the hard-sphere fluid. In the treatment of liquid water,
quasi-chemical theory with soft-cutoff conditioning doesn't change the
fundamental convergence characteristics of the theory using hard-cutoff
conditioning. In fact, hard cutoffs are found here to work better than softer
ones.Comment: 5 pages, 2 figure
Mechanism of Selective Oxidation of Propene to Acrolein on Bismuth Molybdates from Quantum Mechanical Calculations
Storage and separation of CO2 and CH4 in silicalite, C168 schwarzite, and IRMOF-1: A comparative study from Monte Carlo simulation
10.1021/la062289pLangmuir232659-666LANG
Flexibility of Ordered Surface Hydroxyls Influences the Adsorption of Molecules in Single-Walled Aluminosilicate Nanotubes
Single-walled aluminosilicate nanotubes (NTs) are attractive for molecular separation applications because of their highly ordered structure, tunable dimensions, as well as their hydrophilic and functionalizable interiors. These NTs possess a pore surface consisting of an ordered array of silanol groups with flexible hydroxyls. We show that the flexibility of these hydroxyl groups is critical in the adsorption of hydrogen-bonding molecules. Specifically, we study the adsorption of water, methanol, CO<sub>2</sub>, and CH<sub>4</sub> in the NT via grand canonical Monte Carlo (GCMC) simulations. The experimentally observed hydrophilicity of the surface can be captured in adsorption calculations only if the structural and orientational flexibility of the surface hydroxyls is incorporated. The adsorption selectivity of water over methanol is predicted to be larger than 100, which makes aluminosilicate NTs promising for dehydration of alcohols. Flexibility effects are less significant for the adsorption of non-hydrogen-bonding molecules
Using operando techniques to understand and design high performance and stable alkaline membrane fuel cells
On the Inflection in the Concentration Dependence of the Maxwell−Stefan Diffusivity of CF 4
Decomposition pathways of an alkaline fuel cell membrane material component via evolved gas analysis
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