A LEED analysis of the structure of

Hayek, K.; Glassl, H.; Gutmann, A.; Leonhard, H.; Prutton, M.; Tear, S.P.; Welton-Cook, M.R.

doi:10.1016/0039-6028(85)90172-4

Cited by 87 publications

(56 citation statements)

References 17 publications

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“…80 and Voi were found to be the same as in Reference 56. Varying a within a reasonable range of 0.5 to 0.9 results in only small changes in the %-factor value.…”

Section: The Effect Of Other Parameterssupporting

confidence: 67%

“…As an additional benefit of reducing the muffin-tin radius, the number of phase shifts required in the LEED computation decreases. In particular, for the Pt(ll1) surface, the results of this phase shift study lead to a large improvement in agreement between theoretical and experimental I-V curves; the agreement represents a 50% improvement over older LEED result^.^^^ 57 We have also examined the effect of various non-structural parameters on the best-fit Pt(lll)-p(2 x 2)-0 structure. We find that details in the construction of the muffintin potential-do not influence the resulting structure.…”

Section: Reliability Of a Leed Structurementioning

confidence: 99%

“…The Pt(ll1)-p(2 x 2)-0 system has been well studied using other technique^^"^^ In addition, the surface geometry of clean Pt(ll1) has been the subject of earlier LEED investigations using R-factor 57 These investigations have never yielded satisfactory R-factors as compared to other clean surfaces. Because clean Pt(ll1) normally has an unreconstructed bulk-periodic surface, these unsatisfactory R-factor d u e s could not be caused by neglecting structural parameters.…”

Section: Introductionmentioning

confidence: 99%

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Surface structures from low energy electron diffraction: Atoms, small molecules and an ordered ice film on metal surfaces

Materer¹

1995

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“…80 and Voi were found to be the same as in Reference 56. Varying a within a reasonable range of 0.5 to 0.9 results in only small changes in the %-factor value.…”

Section: The Effect Of Other Parameterssupporting

confidence: 67%

Section: Reliability Of a Leed Structurementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Surface structures from low energy electron diffraction: Atoms, small molecules and an ordered ice film on metal surfaces

Materer¹

1995

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“…The chemistry has analogies in HzS reactivity at a Pt(ll1) surface (21) and addition of HzS to Pt3(p3-CO) (~-d p m )~' + (20). Reaction of H 2 0 with zirconocene species to give a p-0x0 derivative with Hz evolution was also presented as proceeding via oxidative addition and a subsequent proton transfer (8).…”

Section: Discussionmentioning

confidence: 99%

Mechanistic aspects of the reaction of hydrogen sulfide with dinuclear palladium(I) complexes containing bis(diphenylphosphino)methane and related ligands

Barnabas¹,

Sallin²,

James³

1989

Can. J. Chem.

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Kinetic and low temperature nmr data are presented for the reaction of hydrogen sulfide with PdzX2(k-dpm)2 species in dichloromethane solution (X = halide, dpm = bis(dipheny1phosphino)methane. The reactions form the corresponding bridgedsulfide, A-frame complex via oxidative-addition of H2S across the Pd-Pd bond to give a hydrido(mercapto) intermediate, that subsequently liberates H, to give Pd2X2(p-S) (~-d p m )~ species. Quantitative kinetic data showing first order behaviour in both Pd2 dimer and H2S concentrations are given for the bromide system over the temperature range 0-3S°C, as well as more limited data for the photosensitive iodide system; plausible mechanisms are discussed. Some qualitative findings are presented for related systems containing 1 ,1-bis(dipheny1phosphino)ethane.Key words: palladium complexes, hydrogen sulfide, bis(dipheny1phosphino)methane.A. FREDDY BARNABAS, DOMINIQUE SALLIN et BRIAN R. JAMES. Can. J. Chem. 67,2009Chem. 67, (1989.On prksente des donnkes relatives a la cinktique ainsi qu'i la rmn a basse tempkrature pour la rkaction du sulfure d'hydrogkne avec les espkces Pd2X2(k-dpm)2 (dans lesquelles X = halogknure et dpm = bis(diphknylphosphino)mkthane), en solution dans le dichloromkthane. Par le biais d'une addition oxydative du H2S a travers la liaison Pd-Pd, les rkactions foment le complexe correspondant, de structure en A et comportant un pont sulfure, qui conduit a un intermkdiaire hydrido(mercapto) et qui libkie par la suite du H2 pour foumir des espkces Pd2X2(k-S) ( k -d~r n )~. Des donnkes cinktiques quantitatives dkmontrent que, pour le systkme du bromure i d e s ternpkratures allant de 0 a 30°C et pour des donnkes plus limitkes relatives au systkme photosensibilisk de l'iodure, les rkactions sont du premier ordre relativement aux concentrations tant du dimkre Pd2 que du H2S; on discute de divers mkcanismes plausibles. On presente quelques donnkes qualitatives concemant des systkmes apparentks contenant du 1 , 1-bis(diphCny1phosphino)Cthane.

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“…These efforts have included work on close-packed surfaces of transition (Co(0 0 0 1) [9], Ru(0 0 0 1) [27][28][29][30], Ir(1 1 1) [31], Ni(1 1 1) [32][33][34][35], Pd(1 1 1) [36][37][38][39][40], Pt(1 1 1) [41][42][43][44], Rh(1 1 1) [45][46][47]) and noble metals (Ag(1 1 1) [12,48,49], Au(1 1 1) [50][51][52], Cu(1 1 1) [53][54][55]). The formation of ( p 3 Â p 3) R30°structure on the (1 1 1) surfaces was frequently observed while the (2 Â 2) structure was commonly reported on the (0 0 0 1) face.…”

Section: Introductionmentioning

confidence: 99%

First-principles studies of H2S adsorption and dissociation on metal surfaces

2008

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Exposure of Pd-based hydrogen purification membranes to H,S. a common contaminant in coal gasification streams, can cause membrane performance to deteriorate, either by deactivating surface sites required for dissociative H, adsorption or by forming a low-permeability sulfide scale. In this work. the composition, structure, and catalytic activity of Pd4S, a surface scale commonly observed in Pd-membrane separation of hydrogen from sulfur-containing gas streams, were examined using a combination of experimental characterization and density functional theory (DFT) calculations. A Pd,S sample was prepared by exposing a 100 f1m Pd foil to H2S at 908 K. Both X-ray photoemission depth profiling and low energy ion scattering spectroscopic (LEISS) analysis reveal slight sulfur-enrichment of the top surface of the sample. This view is consistent with the predictions of DFT atomistic thermodynamic calculations. which identified S-terminated Pd,S surfaces as energetically favored over corresponding Pd-terminated surfaces. Activation barriers for H2 dissociation on the Pd,S surfaces were calculated. Although barriers are higher than on Pd(lll). transition state theory analysis identified reaction pathways on the S-terminated surfaces for which hydrogen dissociation rates are high enough to sustain the separation process at conditions relevant to gasification applications.

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A LEED analysis of the structure of

Cited by 87 publications

References 17 publications

Surface structures from low energy electron diffraction: Atoms, small molecules and an ordered ice film on metal surfaces

Surface structures from low energy electron diffraction: Atoms, small molecules and an ordered ice film on metal surfaces

Mechanistic aspects of the reaction of hydrogen sulfide with dinuclear palladium(I) complexes containing bis(diphenylphosphino)methane and related ligands

First-principles studies of H2S adsorption and dissociation on metal surfaces

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