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A thermodynamic analysis based on the osmotic ensemble scheme enables the prediction of structural changes occurring in silicalite-1 zeolite upon halocarbon molecule adsorption. [ABSTRACT FROM AUTHOR]

An introduction is presented in which editor discusses various articles within the issue on topics including review of metal-organic frameworks (MOF) containing neutral N-donor ligands, link between defects and the catalytic properties of MOFs and dynamic MOF responses to pressure.

Lambda phage DNA and DPPC thin films are imaged in liquids by atomic force microscopyapplying the amplitude modulation mode (‘tapping mode’) with active enhancement of theQ-factorby a ‘Q-control’ electronics. The topography of the resulting images is compared with images obtained withoutactive Q-control. To enable a meaningful comparison, individual scan lines are alternately recorded with andwithout Q-factor enhancement using scan parameters optimized for each mode separately.As the major finding, significant height differences of topographical featuresare observed between the two modes. The heights measured with activeQ-control are reproducibly higher compared to the ones observed withoutQ enhancement. This effect is attributed to the reduction of tip–sample forces byQ-control. [ABSTRACT FROM AUTHOR]

We present a synergistic experimental and theoretical study of CO2/CH4mixture coadsorption in breathing metal–organic framework MIL-53(Al). Mixture adsorption experiments were performed and their results were analyzed by comparing them to predictions made from pure-component adsorption data using the Osmotic Framework Adsorption Solution Theory (OFAST). This analytical model, fully validated for the first time, was then used to predict coadsorption properties as a function of temperature, pressure, and mixture composition. The phase diagrams obtained show a surprising non-monotonic behavior. [ABSTRACT FROM AUTHOR]

The bonding of single diferrocene [Fc(CH2)14Fc, Fc = ferrocenyl] molecules on a metal surface can be enhanced by partial decomposition of Fc groups induced by the tunneling current in scanning tunneling microscopy. Although the isolated intact molecule is mobile on the terrace of Cu(110) at 78 K, the modified molecule is immobilized on the terrace. Calculations based on density functional theory indicate that the hollow site of the Cu(110) surface is the energetically favorable adsorption site for both ferrocene and the Fe−cyclopentadienyl complex, but the latter one possesses a much higher binding energy with the substrate. [ABSTRACT FROM AUTHOR]

We report a joint experimental and molecular simulation study of water condensation in silicalite-1 zeolite. A sample was synthesized using the fluoride route and was found to contain essentially no defects. A second sample synthesized using the hydroxide route was found to contain a small amount of silanol groups. The thermodynamics of water condensation was studied in these two samples, as well as in a commercial sample, in order to understand the effect of local defects on water adsorption. The molecular simulation study enabled us to qualitatively reproduce the experimentally observed condensation thermodynamics features. A shift and a rounding of the condensation transition was observed with an increasing hydrophilicity of the local defect, but the condensation transition was still observed above the water saturation vapor pressure P0. Both experiments and simulations agree on the fact that a small water uptake can be observed at very low pressure, but that the bulk liquid does not form from the gas phase below P0. The picture that emerges from the observed water condensation mechanism is the existence of a heterogeneous internal surface that is overall hydrophobic, despite the existence of hydrophilic “patches”. This heterogeneous surface configuration is thermodynamically stable in a wide range of reduced pressures (from P/P00.2 to a few thousands), until the condensation transition takes place. [ABSTRACT FROM AUTHOR]

Submolecular features of epitaxially grown 3,4,9,10-perylenetetra-carboxylic-dianhydride (PTCDA) on Cu(111) are resolved in non-contact atomic force microscopy topography scans in ultrahigh vacuum. While molecules in the first layer above the Cu substrate are depicted as featureless ovals, the second layer molecules show an intramolecular structure with a height corrugation of up to 40 pm. Force field spectroscopy experiments with submolecular resolution show that the tip-molecule forces differ significantly on the first and second layer molecules. Possible contributions to these force differences from mechanical deformations of the molecules as well as the internal charge density distribution are discussed. [ABSTRACT FROM AUTHOR]