Possible effect of static surface disorder on diffractive scattering of H from Ru(0001): Comparison between theory and experiment.

Specific features of diffractive scattering of H from metal surfaces can serve as fingerprints of the reactivity of the metal towards H, and in principle theory-experiment comparisons for molecular diffraction can help with the validation of semi-empirical functionals fitted to experiments of sticking of H on metals. However, a recent comparison of calculated and Debye-Waller (DW) extrapolated experimental diffraction probabilities, in which the theory was done on the basis of a potential energy surface (PES) accurately describing sticking to Ru(0001), showed substantial discrepancies, with theoretical and experimental probabilities differing by factors of 2 and 3. We demonstrate that assuming a particular amount of random static disorder to be present in the positions of the surface atoms, which can be characterized through a single parameter, removes most of the discrepancies between experiment and theory.

Dynamics of H dissociation on the close-packed (111) surface of the noblest metal: H + Au(111).

We have performed calculations on the dissociative chemisorption of H on un-reconstructed and reconstructed Au(111) with density functional theory, and dynamics calculations on this process on un-reconstructed Au(111). Due to a very late barrier for dissociation, H + Au(111) is a candidate H-metal system for which the dissociative chemisorption could be considerably affected by the energy transfer to electron-hole pairs. Minimum barrier geometries and potential energy surfaces were computed for six density functionals.

Performance of a Non-Local van der Waals Density Functional on the Dissociation of H2 on Metal Surfaces.

van der Waals functionals have recently been applied to obtain a potential energy surface to describe the dissociation of H2 on Ru(0001), where an improvement was found for computed reaction probabilities compared to experiment, which could not be achieved with the use of other exchange-correlation functionals. It is, however, not yet clear to what extent van der Waals functionals give a better description of other molecule-metal surface systems. In this study, the optPBE-vdW-DF functional is compared to the SRP48 functional, which was originally fitted to describe the dissociation of H2 on Cu(111), in terms of the resulting potential energy surfaces and results of quasi-classical dynamics calculations and their agreement with experiment for different H2-metal surface systems.

Thermal lattice expansion effect on reactive scattering of H2 from Cu(111) at T(s) = 925 K.

Surface phonons and surface temperature may have important effects on reactions of molecules at surfaces, and at present much remains unknown about these effects. A question addressed here, which has received little attention so far, is how reaction at elevated temperature is affected by thermal lattice expansion. To answer this question for the benchmark reaction of H2 and D2 with Cu(111), we have performed quantum and quasi-classical dynamics calculations.

Identification of potent and selective glucosylceramide synthase inhibitors from a library of N-alkylated iminosugars.

Glucosylceramide synthase (GCS) is an important target for clinical drug development for the treatment of lysosomal storage disorders and a promising target for combating type 2 diabetes. Iminosugars are useful leads for the development of GCS inhibitors; however, the effective iminosugar type GCS inhibitors reported have some unwanted cross-reactivity toward other glyco-processing enzymes. In particular, iminosugar type GCS inhibitors often also inhibit to some extent human acid glucosylceramidase (GBA1) and the nonlysosomal glucosylceramidase (GBA2), the two enzymes known to process glucosylceramide.