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1.	Andersen, J. N., et al. (författare) Alkali metal adsorption on Al(111) 1993 Ingår i: Surface Science. - : Elsevier BV. - 0039-6028. ; 289:3, s. 307-334 Tidskriftsartikel (refereegranskat)abstract The submonolayer adsorption of Na, K, Rb, and Cs on the Al(111) surface at 100 K and at room temperature is investigated by high resolution core level spectroscopy and low energy electron diffraction. It is found that the first alkali atoms on the surface adsorb at surface defects. At higher coverages, up to approximately one third of the maximum submonolayer coverage, alkali atoms adsorbed at defects coexist with a dispersed phase. At higher coverages island formation is found to occur for the majority of the systems. It is argued that all of the ordered structures formed at room temperature involve a disruption of the Al(111) surface in contrast to the situation at 100 K where the alkali atoms adsorb as adatoms.
2.	Andersson, Martin, et al. (författare) Anharmonic resonances in the C-H stretch region of ethoxy adsorbed on W(110): vibrational spectroscopy and calculations 2003 Ingår i: Surface Science. - 0039-6028. ; 532-535, s. 221-226 Tidskriftsartikel (refereegranskat)abstract We show that it is possible to understand and interpret the complex and rich C-H stretch region in the vibrational spectrum of ethoxy adsorbed on W(110) in terms of fundamental C-H stretch modes in Fermi resonance with C-H deformation overtones and combinations. The mode assignment is based on calculated C-13 isotopic shifts for an ethoxy-Cu-5 cluster. The coupling constants have been derived from calculated energy third derivatives of free ethanol and the coupling was implemented by an effective Hamiltonian matrix. The agreement with experiments is very good.
3.	Borg, Mikael, et al. (författare) Structure and formation of the Al(100)-(root 5 x root 5) R27 degrees-Na phase: a LEED, DFT and HRCLS study 2002 Ingår i: Surface Science. - 0039-6028. ; 515:2-3, s. 267-280 Tidskriftsartikel (refereegranskat)abstract Adsorption of 0.2 ML Na on Al(1 0 0) at room temperature yields a disordered Al(1 0 0)-(1 x 1)-Na phase, which transforms reversibly to a well-ordered Al(1 0 0)-(root5 x root5)R27degrees-Na phase on cooling below 250 K. Based on low energy electron diffraction (LEED) and high resolution core-level spectroscopy (HRCLS) measurements, and on ab initio calculations, it is concluded that the structure of the Al(1 0 0)-(root5 x root5-)R27degrees-Na phase consists of Na atoms occupying substitutional sites. The structural parameters obtained from LEED and density functional theory analyses are in quantitative agreement. Adsorption of 0.2 ML Na at 100 K yields an Al(1 0 0)-c(2 x 2)-Na island structure, which transforms irreversibly into the (root5 x root5)R27degrees-Na structure by annealing above 190 K. The nature of the reversible and irreversible phase transformations to the (root5 x root5)R27degrees structure is investigated by HRCLS and LEED. (C) 2002 Elsevier Science B.V. All rights reserved.
4.	Carlsson, Anna K, 1966, et al. (författare) Oscillatory photoemission cross section for alkali monolayer quantum well states 1996 Ingår i: Surface Science. - : Elsevier BV. - 0039-6028. ; 352-354, s. 656-659 Tidskriftsartikel (refereegranskat)abstract A strong oscillatory photon energy dependence, observed in the photon energy range between 5 and 26 eV, for the intensity of photoemission peaks due to quantum well states in Na and Cs monolayers on Cu(111) is ascribed to interference between the contributions to the outgoing photoelectron wave from the two tails of the quantum well state.
5.	Carlsson, A, et al. (författare) Strain state in semiconductor quantum dots on surfaces : a comparison of electron microscopy and finite element calculations 1998 Ingår i: Surface Science. - 0039-6028. ; 406:1-3, s. 48-56 Tidskriftsartikel (refereegranskat)abstract The strain distribution in InP quantum dots, coherently grown on a GaInP substrate, was determined by image analysis of high-resolution electron microscopy images. Image simulations were used to verify the obtained results. The measured strain values were compared with values obtained from finite element calculations, using the dot shape determined by electron microscopy. The measured and calculated strain values are in good agreement, supporting the use of finite element calculations for strain determination in quantum dots.
6.	Heskett, D., et al. (författare) Alkali-alkali interactions on Al(111) : segregation and islanding in Na-Rb mixtures 1994 Ingår i: Surface Science. - 0039-6028. ; 316:3, s. 303-308 Tidskriftsartikel (refereegranskat)abstract The low temperature coadsorption of Na and Rb on an Al(111) surface is examined with a combination of LEED and core level photoemission spectroscopy. We observe LEED pattern sequences and alkali core level binding energies which are consistent with a net total alkali coverage and can be explained by Na-Rb repulsion, segregation, and islanding, though other models cannot be definitely excluded.
7.	Jacobsen, SN, et al. (författare) Sharp microfaceting of (001)-oriented cerium dioxide thin films and the effect of annealing on surface morphology 1999 Ingår i: Surface Science. - 0039-6028. ; 429:1-3, s. 22-33 Tidskriftsartikel (refereegranskat)abstract Cerium dioxide, CeO2, is a chemically stable oxygen-ion-conducting material, which has been extensively used as an additive or support in oxidation catalysts. The fact that catalytic behaviour is often surface structure sensitive and/or edge atom dependent suggests that different surfaces might be discernible in associated redox processes. Thus, it is desirable to realise CeO2 films with a well-defined microstructure and with crystallographically uniform surfaces. In this paper we present evidence of extremely sharp microfaceting on the surface of thin CeO2 films grown by r.f. magnetron sputtering, and the effect of annealing on the formed sharp ridges. The results show that nominally designated crystallographic surfaces may in fact not coincide with the surfaces exposed as-grown. Thus, there is a clear risk for erroneous interpretation of various orientation-dependent surface properties. Carefully controlled annealing of these films can be utilised as a method for tailoring the resulting surface morphology on the atomic scale.
8.	Jaworowski, A. J., et al. (författare) Adsorption sites in O and CO coadsorption phases on Rh(111) investigated by high-resolution core-level photoemission 1999 Ingår i: Surface Science. - 0039-6028. ; 431:1, s. 33-41 Tidskriftsartikel (refereegranskat)abstract High-resolution core-level spectroscopy is used in combination with low-energy electron diffraction (LEED) and photoelectron diffraction to identify the adsorption sites for three different coadsorbed phases consisting of ordered overlayers of oxygen coadsorbed with CO on the Rh(111) single-crystal surface. The three ordered overlayer structures, which may be denoted as 2O + CO/Rh(111), O + CO/Rh(111) and O+2CO/Rh(111), all show (2 × 2) LEED patterns. In the 2O + CO and O + CO phases the CO molecules are found to occupy only on-top sites while the O + 2CO phase shows CO molecules in both on-top and three-fold hollow sites. In all cases the oxygen atoms are found in three-fold hollow sites. For the O + CO and O + 2CO phases our results confirm previous determinations by LEED, while the 2O + CO phase has not been observed before on Rh(111). The core-level binding energies of the C 1s and O 1s core levels for both adsorbates are characteristics of the adsorption site and are very close to the binding energies found for the pure cases of only oxygen or CO adsorbed on Rh(111). In the coadsorption phases we find that the interaction between the adsorbates has only a minor influence on the core-level binding energies. For the O + 2CO/Rh(111) coadsorption phase we find that a full CO coverage is not obtained; less than 80% of the unit cells contain two CO molecules, in line with previous findings.
9.	Jaworowski, A J, et al. (författare) Determination of NO adsorption sites on Pd(100) using core level photoemission and low energy electron diffraction 2002 Ingår i: Surface Science. - 0039-6028. ; 501:1-2, s. 74-82 Tidskriftsartikel (refereegranskat)abstract The adsorption of NO on Pd(1 0 0) is investigated with high resolution core level spectroscopy and low energy electron diffraction (LEED). Several ordered NO overlayers were observed, in agreement with earlier Studies. Our data clearly show that NO adsorbs in fourfold hollow sites at coverages tip to 0.25 -0.30 monolayer (ML) whereas at 0.5 ML only bridge sites are occupied. By a reinterpretation of previous electron energy loss spectroscopy (EELS) investigations we show that the new site assignments are in agreement the EELS data, Based on the photoemission results for the N 1s and the Pd 3d core levels we propose new structure models for the (2root2 x 2root2)R45degrees and the p(4 x 2) LEED patterns found at coverages of 0.5 and 0.25 ML, respectively. In the latter case, it is suggested that the p(4 x 2) LEED pattern is formed from domains having p(2 x 2)-NO and c(4 x 2)-2NO unit cells.
10.	Jaworowski, AJ, et al. (författare) Mn-induced NO dissociation on Pd(100) 2002 Ingår i: Surface Science. - 0039-6028. ; 501:1-2, s. 83-92 Tidskriftsartikel (refereegranskat)abstract The changes in the NO adsorption properties of Pd(1 0 0) due to the addition of Mn have been investigated using high resolution core level photoelectron spectroscopy. The Pd(1 0 0) surface was modified by forming a c(2 x 2)-PdMn surface alloy at two different Mn coverages, giving surfaces partly and fully alloyed, respectively, as shown by scanning tunneling microscopy. NO adsorption on the alloy films was found to destroy the c(2 x 2) structure. Dissociation of the NO molecules upon heating is observed, in stark contrast to NO on the clean Pd(1 0 0) surface from which all the molecules desorb intact upon heating. The dissociation process on the c(2 x 2)-PdMn-(1 x 1)-Pd mixed surface is completed at a significantly higher temperature than for the homogeneous c(2 x 2) surface. It is suggested that Mn atoms give rise to NO dissociation at lower temperatures. whereas Pd atoms situated at c(2 x 2)-(1 x 1) boundaries are responsible for the NO decomposition at higher temperatures.
11.	Johansson, L. I., et al. (författare) Surface core level shift on Be( 112̄0) 1994 Ingår i: Surface Science. - : Elsevier BV. - 0039-6028. ; 321:3 Tidskriftsartikel (refereegranskat)abstract A photoemission study of the Be(112̄0) surface carried out at a sample temperature of 100 K is reported. A surface shifted Be 1s component, having a shift of - 410 meV, is resolved on this surface. The extracted surface to bulk intensity ratio indicate that this component originates from atoms in the surface layer only. This is opposite to previous observations on both the close-packed Be(0001) surface and the Be(101̄0) surface where sub-surface shifted Be 1s levels were unambiguously identified. Among these three surfaces a surface layer atom is expected to have the lowest coordination on the (112̄0) surface but the surface layer shift is found to be smallest on this surface. Compared to findings on other metals this is unusual and reasons contributing to this behaviour are suggested and discussed.
12.	Lundgren, Edvin, et al. (författare) A misfit structure in the Co/Pt(111) system studied by scanning tunnelling microscopy and embedded atom method calculations 2002 Ingår i: Surface Science. - 0039-6028. ; 498:3, s. 257-265 Tidskriftsartikel (refereegranskat)abstract We have performed scanning tunnelling microscopy (STM) measurements of thin films of Co and CoPt alloys on Pt(111). In contrast to the interpretation of an earlier low energy electron diffraction investigation by Tsay and Shern [Surf. Sci. 396 (1998) 313] we find that the structure observed upon annealing a Pt(111) sample with a 2 ML (monolayer, ML) thick film of Co does not consist of a rotated Co film but rather of a CoPt alloy film with hexagonal areas of fee stacking, single and double stacking faults, delimited by misfit dislocations (Shockley partial dislocations). Comparison of STM images with embedded atom method calculations confirms our model. The structure at the Pt-PtCo interface in our model is similar to that proposed by Henzler [Surf. Sci. 419 (1999) 321].
13.	Lundgren, E., et al. (författare) Layer dependent core level binding energy shifts : Na, K, Rb and Cs on Al(111) 1993 Ingår i: Surface Science. - 0039-6028. ; 281:1-2, s. 83-90 Tidskriftsartikel (refereegranskat)abstract Layer resolved core level spectra are presented for Na, K, Rb and Cs films on Al(111). From the development of the spectra, it is possible to distinguish emission from alkali atoms at the interface, in the bulk, and at the surface of the adsorbed layers. The core level binding energy shifts are discussed in terms of adhesion and interface segregation energies. It is found experimentally that the Al induced core level binding energy shifts of the alkalis are increasing with increasing atomic number of the alkali metal. This trend is qualitatively reproduced by semi-empirical calculations.
14.	Lundgren, E., et al. (författare) On the temperature induced transformation between the two Al(111)-(√3 × √3)R30°-Rb structures 1995 Ingår i: Surface Science. - : Elsevier BV. - 0039-6028. ; 343:1-2, s. 37-43 Tidskriftsartikel (refereegranskat)abstract The dynamics of the temperature induced transformation between low and high temperature adsorption phases of Rb on Al(111) has been followed by high resolution core level spectroscopy. Particular emphasis has been paid to the order-preserving transformation between the low and high temperature Al(111)-Rb-(√3 × √3)R30° structures in which Rb atoms occupy on-top and substitutional sites, respectively. For a Rb coverage of 0.33 monolayer the rate of conversion from on-top ti substitutional sites is found to increase strongly at 250 K. For Rb coverages below 0.33 but above approximately 0.14 monolayers the conversion occurs at lower temperatures. Increasing the coverage above 0.33 monolayers increases the conversion temperature. The possibility to detect the Al atoms which are expelled from the first Al layer during the conversion is demonstrated.
15.	Nyholm, R., et al. (författare) EPITAXIAL SILICIDE FORMATION IN THE MG/SI(111) SYSTEM 1993 Ingår i: Surface Science. - : Elsevier BV. - 0039-6028 .- 1879-2758. ; 289:3, s. 290-296 Tidskriftsartikel (refereegranskat)abstract The silicide formation has been studied in the Mg/Si(111) system by IOW energy electron diffraction (LEED) and photoelectron spectroscopy. It has been found that an epitaxial Mg2Si silicide is responsible for the (2/3 square-root e x 2/3 square-root 3)R30-degrees reconstruction in this system. The thickness of the silicide is limited due to the very low formation temperature for this silicide. The Fermi level is positioned 0.59 +/- 0.06 eV above the valence band maximum in the Si substrate and the valence band maximum in the epitaxial silicide is positioned 0.3 +/- 0.1 eV below the Fermi level.
16.	Nyholm, R., et al. (författare) FORMATION OF SM SILICIDES ON SI(111) - COMPOSITION AND EPITAXY 1993 Ingår i: Surface Science. - 0039-6028 .- 1879-2758. ; 293:3, s. 254-259 Tidskriftsartikel (refereegranskat)abstract The formation of Sm silicides on Si(111) by means of solid phase epitaxy has been studied with low energy electron diffraction, Auger electron spectroscopy and photoelectron spectroscopy of the Sm 4f level and Si 2p level. A limited reaction is found to occur already at room temperature whereas at higher temperatures a strongly intermixed Sm/Si layer showing some long range order is formed. The Sm atoms of this intermixed phase are found to be completely trivalent in accordance with expectations. The intermixed layer consists of two silicides with different compositions, one of them being SmSi2-x, the other being tentatively ascribed to SmSi.
17.	Olsson, Louise, 1974, et al. (författare) Role of Steps in the NO-CO Reaction on the (111) Surface of Noble Metals 2003 Ingår i: Surface Science. - 0039-6028. ; 529:3, s. 338-348 Tidskriftsartikel (refereegranskat)abstract One of the most probable scenarios of the NO-CO reaction on the (111) surface of noble metals includes reversible NO and CO adsorption, NO dissociation, N-2 desorption, and CO2 formation due to reaction between adsorbed CO and 0 species. Adopting this scheme, we analyze the reaction kinetics in the situation when the surface contains steps. Employing the mean-field kinetic equations with the kinetic parameters corresponding to the case when the adsorbate coverage is high and the reaction rate is limited by NO dissociation, we show that the contribution of steps to the reaction rate may be appreciable. The adsorbate-diffusion-mediated communication between terraces and steps can play a constructive role in the reaction, i.e., the reaction rate may be higher with than without communication. In addition, we present Monte Carlo simulations demonstrating that, due to limitations in the rate of N diffusion, the adsorbate distribution along the surface may be non-uniform with the largest N coverage near steps. Such reaction regimes are found to be possible even for relatively high rates of N diffusion (e.g., in the case when the ratio of the rates of N jumps and CO or NO impingement is about 10(4)). The implications of these findings for the understanding of the specifics of the reaction under consideration are briefly discussed.
18.	Over, H, et al. (författare) Experimental and simulated STM images of stoichiometric and partially reduced RuO2(110) surfaces including adsorbates 2002 Ingår i: Surface Science. - 0039-6028. ; 515:1, s. 143-156 Tidskriftsartikel (refereegranskat)abstract We present experimental and DFT-simulated STM images of ultrathin RuO2(110) films on Ru(0001), including adsorbates such as oxygen and CO. We are able to identify the under-coordinated O atoms on the RuO2(110) surface with STM, i.e. the bridging O atoms and the on-top O atoms. The partial reduction of the RuO2(110) surface by CO exposure at room temperature leads to a surface where part of the bridging O atoms have been removed and some of the vacancies are occupied by bridging CO. When dosing 10 L of CO at room temperature, the RuO2(110) surface becomes fully mildly reduced in that all bridging 0 atoms are replaced by bridging CO molecules. Annealing the surface to 600 K produces holes on the terraces of such a mildly reduced RuO2(110) surface. These pits are not generated by the recombination of lattice O with CO, but rather these pits are assigned to a complex temperature-induced rearrangement of surface atoms in the topmost RuO2 double layer of RuO2(110). With this process the bridging O atoms are again populated and surplus Ru atoms agglomerate in small islands at the rims of the holes. (C) 2002 Elsevier Science B.V. All rights reserved.
19.	Over, H, et al. (författare) On the origin of the Ru-3d(5/2) satellite feature from RuO2(110) 2002 Ingår i: Surface Science. - 0039-6028. ; 504:1-3, s. 196-200 Tidskriftsartikel (refereegranskat)abstract High resolution core level spectroscopy in combination with density functional theory calculations are used to study the satellite feature of the Ru-3d(5/2), core level spectrum whose interpretation is still a matter of debate. We present evidence that the satellite peak is not related to any structural properties of the RuO2(1 1 0) surface. The binding energy shift between the Ru-3d(5/2) component and the satellite peak is close to the electron energy loss due to plasmon excitation. We propose therefore that the satellite peak is due to excitation of the RuO2 plasmon. (C) 2002 Elsevier Science B.V. All rights reserved.
20.	Sandell, A, et al. (författare) Metalorganic Chemical Vapor Deposition of Anatase Titanium Dioxide on Si: Modifying the Interface by Pre-Oxidation. 2003 Ingår i: Surface Science. - 0039-6028 .- 1879-2758. ; 530:1-2, s. 63-70 Tidskriftsartikel (refereegranskat)abstract The formation of TiO2 films on clean and pre-oxidized Si(1 1 1) through chemical vapor deposition of titanium(IV) isopropoxide (TTIP) in ultra-high vacuum has been examined by synchrotron radiation photoelectron spectroscopy, X-ray absorption spectroscopy (XAS) and scanning tunneling microscopy. In both cases, TTIP deposition at 500 °C eventually results in an anatase TiO2 film with a carbon-free surface and the surface morphology of the anatase films is very similar. By using a novel way of combining photoemission and XAS data, it is demonstrated that the two situations have substantially different interfacial properties. Pre-oxidation of the surface at 500 °C passivates the surface so that the thickness of the amorphous TiSixOy interface layer decreases from 30–35 to 15–25 Å and eliminates the formation of interfacial carbon completely.
21.	Sandell, Anders, et al. (författare) Surface chemistry of TiCl4 on clean and hydrogen modified W(110): identification of surface intermediates 2002 Ingår i: Surface Science. - 0039-6028. ; 521:3, s. 129-138 Tidskriftsartikel (refereegranskat)abstract The adsorption and decomposition of titanium tetrachloride (TiCl4) on W(110) were studied with high-resolution core level photoelectron spectroscopy. At least two stable intermediates are formed along the pathway to TiCl4 decomposition: TiCl4(a), which is stable up to 300 K, and TiCl3(a), which is stable up to 500 K. Successive adsorption at 80 K shows that the TiCl4() species forms in the presence of dissociated TiCl4 or hydrogen. This indicates that dissociative sites must be blocked before TiCl4 can adsorb intact.
22.	Schmidt-May, J., et al. (författare) Resonant electron and ion emission and desorption mechanism in rare earth oxides 1985 Ingår i: Surface Science. - : Elsevier BV. - 0039-6028. ; 163:2-3, s. 303-314 Tidskriftsartikel (refereegranskat)abstract The resonant enhancement in photoelectron spectra at the 4d edges of rare earth atoms and metals is also found in yield spectra of desorbed ions from the surfaces of the oxides of Sm, Eu and Yb following the photon excitation. The analysis of the 4d → 4f resonance leads to a picture of an indirect mechanism of ion desorption which is mainly caused by the flux of energetic 4f photoelectrons from the bulk. In this case the dominant desorption through secondary processes limits the use of the photon-stimulated desorption (PSD) to determine to which type of atom the desorbing species was attached.
23.	Schnadt, Joachim, et al. (författare) Structural study of adsorption of isonicotinic acid and related molecules on rutile TiO2(110) I: XAS and STM 2003 Ingår i: Surface Science. - 0039-6028. ; 540:1, s. 39-54 Tidskriftsartikel (refereegranskat)abstract X-ray absorption spectroscopy (XAS) and scanning tunneling microscopy (STM) have been used to study the absorption of monolayers of the pyridinecarboxylic acid monomers (isonicotinic acid, nicotinic acid, and picolinic acid) and benzoic acid on a rutile TiO2(1 1 0) surface. We find that the pyridine and phenyl rings are oriented with their planes largely perpendicular to the surface. The azimuthal orientations are strongly influenced by adsorbate-adsorbate interactions, which in each case leads to at least two different molecular species. In order to reach this conclusion a detailed strategy has been developed for the interpretation of angle-dependent XAS data, which does not rely on any curve fitting procedures. (C) 2003 Elsevier B.V. All rights reserved.
24.	Smedh, M., et al. (författare) Vibrationally resolved C Is photoemission from CO absorbed on Rh(1 1 1) : The investigation of a new chemically shifted C Is component 2001 Ingår i: Surface Science. - 0039-6028. ; 491:1-2, s. 99-114 Tidskriftsartikel (refereegranskat)abstract High-resolution core-level photoemission at an energy resolution better than the intrinsic width of the C 1s level has been used to study the CO/Rh(1 1 1) overlayer system. C Is spectra have been measured in a large CO coverage range; from low coverages, where the CO molecules only adsorb in on-top positions, to saturation coverage, where CO molecules occupy both on-top and threefold hollow sites. Fine structure components due to vibrational excitation of the C-O stretch mode are clearly resolved in the emission peak from each site. The vibrational splittings and intensity ratios are found to be different for the different adsorption sites. A third C Is component, which has not been resolved earlier, is found at intermediate CO coverages. Some possible explanations for the origin of this extra component are discussed. In the light of its binding energy and vibrational energy in photoemission, together with supporting evidence from highresolution electron energy loss spectroscopy data and photoelectron diffraction, this is assigned to bridging CO species at intermediate coverages.
25.	Stierle, A, et al. (författare) Surface core level shift observed on NiAl(110) 2003 Ingår i: Surface Science. - 0039-6028. ; 529:3, s. 263-268 Tidskriftsartikel (refereegranskat)abstract Using high resolution core level spectroscopy, a surface core level shift towards lower binding energy of -0.13 eV is determined for the 2p level of the outwardly relaxed Al surface atoms on NiAl(110). Density functional theory based calculations with inclusion of final state effects yield a value of -0.14 eV for this shift in excellent agreement with experiment. We show that the initial state approximation yields a value of +0.09 eV, i.e. the inclusion of final state relaxation effects is vital not only to obtain the correct value but even the correct sign for this shift. (C) 2003 Elsevier Science B.V. All rights reserved.
26.	Todorova, M, et al. (författare) The Pd(100)-(root 5 x root 5)R27 degrees-O surface oxide revisited 2003 Ingår i: Surface Science. - 0039-6028. ; 541:1-3, s. 101-112 Tidskriftsartikel (refereegranskat)abstract Combining high-resolution core-level spectroscopy, scanning tunneling microscopy and density-functional theory calculations we reanalyze the Pd(100)-(root5 x root5)R27degrees-O surface oxide phase. We find that the prevalent structural model, a rumpled PdO(001) film suggested by previous low energy electron diffraction (LEED) work [Surf. Sci. 494 (2001) L799], is incompatible with all three employed methods. Instead, we suggest the two-dimensional film to consist of a strained PdO(101) layer on top of Pd(100). LEED intensity calculations show that this model is compatible with the experimental data of Saidy et al. (C) 2003 Elsevier B.V. All rights reserved.
27.	Wallenberg, LR, et al. (författare) On the crystal structure of small gold crystals and large gold clusters 1985 Ingår i: Surface Science. - : Elsevier BV. - 0039-6028. ; 156:1, s. 256-264 Tidskriftsartikel (refereegranskat)abstract A large gold cluster with the formula Au55[(C6H5)3P]12Cl6, was imaged with a high-resolution transmission electron microscope (HRTEM) and a proposed model was confirmed. Growth of gold crystals of approximately 4.0 nm size could be followed, row by row of atoms, with the use of a low light level TV camera and on-line image processing.
28.	Almqvist, Nils (författare) Fractal analysis of scanning probe microscopy images 1996 Ingår i: Surface Science. - : Elsevier BV. - 0039-6028 .- 1879-2758. ; 355:1-3, s. 221-228 Tidskriftsartikel (refereegranskat)abstract The accuracy and precision of several algorithms, including newly developed, for calculating the fractal dimension from scanning probe microscopy images of material surfaces are investigated. The algorithms are based on the area-perimeter method, a variance method or versions of the structure function method. The latter two methods show good correspondence to computer simulated images, with known fractal dimensions, and have successfully been applied also on real images. The results show that these two methods give reliable fractal dimensions and are well suited to describe surface roughness quantitatively.
29.	Amandusson, Helena, et al. (författare) Methanol induced hydrogen permeation through a Pd membrane 1999 Ingår i: Surface Science. - 0039-6028 .- 1879-2758. ; 442:2, s. 199-205 Tidskriftsartikel (refereegranskat)abstract The dehydrogenation of methanol and the subsequent permeation of hydrogen through a 25 μm thick palladium film has been studied in a catalytic membrane reactor. At the temperature studied, 350°C, the decomposition pathway for methanol on clean palladium surfaces is believed to lead to Had and a carbonaceous overlayer. The released hydrogen can either desorb or permeate the palladium membrane. During a continuous supply of methanol hydrogen permeation is reduced and, eventually, totally quenched by the growing carbon monoxide/carbon coverage. Adding oxygen in the methanol supply can balance the increasing carbonaceous coverage through the production of carbon dioxide. In such a case, it is concluded that no CO bond scission occurs. The methanol/oxygen ratio is crucial for the hydrogen permeation rate. Isotope-labelled methanol, CH3OH, CH3OD, CD3OH and CD3OD, shows that it is preferentially the methyl (or methoxy) hydrogen that permeates the membrane.
30.	Andersson, C B M, et al. (författare) Bulk and surface electronic structure of InAs(110) 1998 Ingår i: Surface Science. - 0039-6028 .- 1879-2758. ; 398:3, s. 395- Tidskriftsartikel (refereegranskat)abstract The InAs(110) cleavage surface has been investigated by angle-resolved photoelectron spectroscopy. A separation between the In 4d(5/2) bulk component and the valence band maximum of 16.8 eV is found to be consistent with normal emission spectra. Experimental energy band dispersions, E-i(k), for the four bulk valence bands are established along the Sigma-line of the bulk Brillouin zone. A bulk band structure calculation utilizing the augmented plane-wave method is made. The experimental and calculated E-i(k) dispersions are found to be in good agreement with each other. E-i(k(parallel to)) dispersions for two surface-related structures are established along the lines <(Gamma)over bar>-(M) over bar and (Y) over bar-(M) over bar of the surface Brillouin zone. (C) 1998 Elsevier Science B.V.
31.	Andersson, C B M, et al. (författare) Surface atomic structure of InAs((111)over-bar)2x2 and InSb((111)over-bar)2x2 studied by core level spectroscopy 1996 Ingår i: Surface Science. - : Elsevier BV. - 0039-6028 .- 1879-2758. ; 347:1-2, s. 199-206 Tidskriftsartikel (refereegranskat)abstract Surface sensitive high resolution core level spectroscopy has been applied to the molecular beam epitaxy grown InAs((111) over bar)2 x 2 and InSb((111) over bar)2 x 2 surfaces. For both systems the In 4d core level consists of one dominating component while the Group V core levels are deconvoluted into four components. This analysis is consistent with a surface model where the topmost layer consists entirely of arsenic or antimony. In this model, Group V atoms form trimers bound to Group V atoms in the first double layer, leaving a single Group V rest atom per unit cell.
32.	ANDERSSON, CBM, et al. (författare) SPUTTERED AND ANNEALED INAS(111)OVER-BAR - AN UNRECONSTRUCTED SURFACE 1994 Ingår i: Surface Science. - : Elsevier BV. - 0039-6028 .- 1879-2758. ; 307, s. 885-889 Tidskriftsartikel (refereegranskat)abstract The electronic structure of the InAs(111BAR)1 X 1 surface has been investigated by angle resolved photoelectron spectroscopy along the symmetry lines GAMMAKBAR, GAMMAMBAR, and GAMMAMBAR of the surface Brillouin zone. The bulk valence band structure was calculated using a combination of the linear augmented plane-wave method and the relativistic augmented plane-wave method. We have projected the theoretical bulk band structure onto the surface Brillouin zone to separate surface states from surface resonances. Two surface related structures, S1 and S2, have been observed and their E(i)(k(parallel-to)) dispersions are established. Both S1 and S2 show the symmetry of the 1 X 1 surface Brillouin zone, which is consistent with the observed 1 X 1 LEED pattern. We identify S1 as the As-derived dangling bond state, and S2 is associated with the backbonds connecting the As atoms in the surface layer with the underlying In layer.
33.	BADZIAG, P (författare) ALPHA-SIC(0001)ROOT-3XROOT-3 SURFACE, POSSIBLE MODELS FOR THE RECONSTRUCTION 1995 Ingår i: Surface Science. - : ELSEVIER SCIENCE BV. - 0039-6028 .- 1879-2758. ; 337:1-2, s. 1-7 Tidskriftsartikel (refereegranskat)abstract The paper presents an analysis of the energetics of a few possible candidates for the structural model of the root 3 x root 30 degrees reconstruction of the alpha-SiC(0001) surface. The analysis is based on the semi-empirical, self-consistent, quantum mechanical cluster calculations of MNDO type (AMI parametrization). Models allowing clean stoichiometric, Si rich and C rich as well as hydrogenated surfaces were tested. The results indicate that, unlike in most cases with semiconductor surfaces, here, hydrogenation of the surface facilitates the reconstruction instead of lifting it. The most favourable model for the reconstruction from the calculated surface energy point of view is the one where hydrogenated triangles of C atoms saturate the surface silicon dangling bonds. The structure resembles that of cyclopropane with three of the C-H bonds substituted by the C-Si bonds.
34.	Badziag, P (författare) Can hydrogen stabilize the alpha-SiC(0001)root 3x root 3 surface? 1996 Ingår i: Surface Science. - : ELSEVIER SCIENCE BV. - 0039-6028 .- 1879-2758. ; 352, s. 396-400 Tidskriftsartikel (refereegranskat)abstract The paper presents an analysis of the energetics of a few possible candidates for the structural model of the root 3 X root 3 R30 degrees reconstruction of the alpha-SiC(0001) surface. The analysis is based on the semi-empirical, self-consistent, quantum-mechanical cluster calculations of MNDO-type (AM1 parametrization). Clean stoichiometric, Si rich and C rich surface structures as well as surfaces saturated by hydrogen and the hydroxyl groups are examined and particular care is applied when comparing energies of the structures with different stoichiometries. The results confirm the claim that the most favorable model for the reconstruction is here the one where hydrogenated triangles of C atoms saturate the surface silicon dangling bonds. Moreover, the calculated energies indicate that the reconstructed surface is a result of the desorption of SiO from the 1 X 1 surface originally saturated by hydroxyl groups.
35.	Baudin, Micael, et al. (författare) A molecular dynamics study of MgO(111) slabs 1997 Ingår i: Surface Science. - 0039-6028 .- 1879-2758. ; 375:2-3, s. 374-384 Tidskriftsartikel (refereegranskat)abstract Constant stress - constant temperature molecular dynamics simulations are reported for 30 Angstrom thick crystalline MgO (111) slabs with 2-D periodicity in the temperature range 10-1100 K. The 10 K run was 3.75 ps, the 300 K run was 41.25 ps while the others were 11.25 ps. The shell-model potential was used and the long-range interaction was taken into account with the 2-D Ewald summation technique. Two different models have been used in order to achieve the necessary charge compensation for the polar (111) surface. The relaxation of the surface structure and its temperature dependence have been investigated and compared with bulk MgO. The average coordination number in the surface layer and the surface energy are presented. The dynamics in the slab system is presented in terms of atomic mean-square displacements and vibrational density-of-states curves as a function of depth from the surface. (C) 1997 Elsevier Science B.V.
36.	Baudin, M., et al. (författare) Dynamics, structure and energetics of the (111), (011) and (001) surfaces of ceria 2000 Ingår i: Surface Science. - 0039-6028 .- 1879-2758. ; 468:03-jan, s. 51-61 Tidskriftsartikel (refereegranskat)abstract Molecular dynamics simulations for 20-30 Angstrom thick CeO2 slabs with 2-D periodicity are presented. The three low-index surfaces investigated are(lll), (011) and (001). The simulations were performed within a constant-temperature-constant-pressure ensemble and used the shell-model to describe polarizability. All simulation runs were performed at atmospheric pressure and in the temperature range 10-1100 K. For all three surfaces at both 300 and 1100 K, we find that the surface m.s. displacements are generally larger for the oxide ions than for the cations and that the out-of-plane surface motion is usually larger than the in-plane surface motion. At room temperature, the oxygen m.s. displacements at the (Ill)surface are a factor 1.2 larger than in the bulk, a factor 1.6 for the (011) surface and approximately five times larger at the metastable (001) surface compared to the bulk. The effect of the presence of a surface on the ion dynamics [and on the structure for (011)] persists all the way to the slab centres. even for these rather thick slabs. Our simulations for the polar (001) surface demonstrate that the relative stabilities of different faces and surface terminations can change with temperature, and that it may not always be meaningful to consider one specific user-prepared termination as superior to the others.
37.	Baudin, M., et al. (författare) Metal oxide surface dynamics from molecular dynamics simulations : the alpha-Al2O3(0001) surface 2001 Ingår i: Surface Science. - 0039-6028 .- 1879-2758. ; 474:03-jan, s. 107-113 Tidskriftsartikel (refereegranskat)abstract Constant-stress, constant-temperature (10, 300 and 700 K) molecular dynamics simulations were carried out with shell-model potentials for an infinite crystalline A-terminated alpha -Al2O3(000 1) slab of similar to 25 Angstrom thickness. The surface undergoes considerable relaxation at 10 K, but exhibits ordered surface structures at all three temperatures. The relaxation causes the (0 0 0 1) surface at 10 K to appear oxygen-terminated. The ionic motion within the central and surface regions of the slab system has been analysed in terms of mean-square displacements. At room temperature the (u(2))(surface)/(u(2))(bulk) ratio for the Al ions is approximate to2.5 and when only the out-of-plane surface motion is considered the ratio is as large as approximate to3.5. The O ion motion at the surface is slightly smaller than that of the cations.
38.	Bjorkqvist, M, et al. (författare) Nitride formation and dangling-bond passivation on Si(111)-(7x7) with NH3 1997 Ingår i: Surface Science. - 0039-6028 .- 1879-2758. ; 394:1-3, s. L155-L161 Tidskriftsartikel (refereegranskat)abstract Thermal nitridation of the Si(111)-(7 x 7) reconstructed surface with ammonia has been investigated using scanning tunneling microscopy (STM). True nitride formation in the form of ring-like structures as in stoichiometric silicon nitride (Si3N4) was observed at imperfections on the surface, which otherwise preserved the characteristics of the (7 x 7) reconstruction. However, the ratio of reacted adatoms in the reconstruction never exceeded similar to 50%, indicative of a frustrated saturation behavior for the adatom dangling bonds in the Si(111)-(7 x 7)-NH3 reaction system. (C) 1997 Elsevier Science B.V.
39.	CHAKARIAN, V, et al. (författare) THE ADSORPTION OF I2 ON SI(111)-7X7 STUDIED BY SOFT-X-RAY PHOTOEMISSION 1993 Ingår i: Surface Science. - 0039-6028 .- 1879-2758. ; 296:3, s. 383-392 Tidskriftsartikel (refereegranskat)abstract The adsorption Of I2 on Si(111)-7 x 7 at room temperature is studied with soft X-ray photoelectron spectroscopy. I2 adsorbs dissociatively, forming a mixture of SiI, SiI2 and SiI3 moieties, of which SiI dominates. The Fermi level is pinned near mid-gap, moving slightly towards the conduction band as the I coverage increases. The surface work function increases monotonically with I coverage. The I 4d core-level displays a single chemical state, which decreases in binding energy with increasing coverage. Analysis of the Si 2p core-level spectra shows that the adsorption proceeds first by attachment of I to the dangling bonds of the 7 x 7 unit cell and that, at saturation, 1.57 +/- 0.05 ML of I atoms are adsorbed in 1.10 +/- 0.02 ML of SiI(x) groups. These results indicate that substrate Si-Si bonds are broken by reaction with I2. The total I coverage is limited, however, by the availability Of surface dangling bonds that are required to initiate the dissociation Of I2 molecules.
40.	CHAKAROV, DV, et al. (författare) PHOTOSTIMULATED DESORPTION OF METAL ADATOMS - POTASSIUM ON GRAPHITE 1994 Ingår i: Surface Science. - : Elsevier BV. - 0039-6028 .- 1879-2758. ; 311:3, s. L724-L730 Tidskriftsartikel (refereegranskat)abstract Photodesorption is observed of single K atoms from a graphite surface covered with less than 1 monolayer of potassium. The desorption cross section has a threshold at homegaBAR almost-equal-to 3 eV and a maximum at homega(max)BAR almost-equal-to 4.9 eV. Polarization measurements indicate a substrate-mediated mechanism. The coverage dependence suggests that only the ionic 2D, K-phase is photoactive. The proposed mechanism includes attachment of hot electrons, photoexcited in the bulk, to the K4s adsorbate resonance of energy E(res). The band structure of graphite causes a narrow energy distribution of hot electrons, which yields homega(max)BAR almost-equal-to 2E(res).
41.	Chirita, Valeriu, et al. (författare) Reptation : a mechanism for cluster migration on (111) face-centered-cubic metal surfaces 1999 Ingår i: Surface Science. - 0039-6028 .- 1879-2758. ; 436:1-3, s. L641-L647 Tidskriftsartikel (refereegranskat)abstract Embedded-atom molecular-dynamics simulations were used to follow the diffusion dynamics of compact platinum clusters with up to 19 atoms on Pt(lll). The results reveal a cluster diffusion mechanism on (111) face-centered-cubic (fcc) surfaces involving successive shear translations of adjacent subcluster regions giving rise to reptation, a snake-like gliding motion. We show that for compact clusters with <7 atoms, this mechanism competes energetically with that of island diffusion through concerted motion. However, for cluster sizes of between 8 and similar or equal to 20 atoms, reptation becomes energetically favorable, especially for elongated clusters. Reptation is also shown to be an important migration mechanism for fractal (randomly ramified) and dendritic (symmetrically branched) islands. (C) 1999 Elsevier Science B.V. All rights reserved.
42.	Dannetun, Helen, 1957-, et al. (författare) Dehydrogenation of acetylene and ethylene studied on clean and oxygen covered palladium surfaces 1986 Ingår i: Surface Science. - : Elsevier BV. - 0039-6028 .- 1879-2758. ; 173, s. 148- Tidskriftsartikel (refereegranskat)abstract The interaction of acetylene and ethylene with a clean and oxygen covered Pd surface has been studied at a temperature of 473 K. The measurements were performed on a hydrogen sensitive Pd-MOS structure making it possible to obtain direct information on the dissociation of both hydrogen and oxygen containing species on a palladium surface. Desorption studies were also performed as well as ultraviolet photoelectron spectroscopy and work function measurements. The studies show that both acetylene and ethylene adsorb dissociatively at this temperature leaving mainly carbon on the surface. When an oxygen covered Pd surface is exposed to C2H2 or C2H4 carbon dioxide and water will be formed and desorb until the surface is oxygen free. In the case of acetylene the presence of preadsorbed oxygen does not block or prevent the C2H2 dissociation on the surface. For C2H4, a large preadsorbed oxygen coverage ( 0.45) will have an impeding effect on the dissociation. The CO2 desorption is oxygen coverage dependent contrary to the H2O desorption. This is due to the fact that hydrogen has a large lateral mobility on the surface while carbon has not. Both the CO2 and H2O reactions are, however, due to the same type of mechanisms.
43.	Dannetun, Helen, 1957-, et al. (författare) Reactions between hydrocarbon and an oxygen covered palladium surface 1988 Ingår i: Surface Science. - : Elsevier BV. - 0039-6028 .- 1879-2758. ; 193, s. 109- Tidskriftsartikel (refereegranskat)abstract Isothermic desorption studies where an oxygen covered polycrystalline Pd surface (T = 325–575 K) is exposed to small unsaturated hydrocarbons have been performed. The studied gases were acetylene, propene, propadiene, propyne, butene, butadiene, butyne, and also for comparison hydrogen. Electron energy loss spectroscopy (EELS) was available for adsorbate studies and a hydrogen sensitive Pd-MOS structure was used as a sample. The temperature limit for total dissociation is observed to decrease slightly for an oxygen covered surface compared to the clean surface. On an oxygen covered surface the dissociation is complete above 400 K and the reaction products are H2O, CO2, and adsorbed C. Varying the adsorption temperature, the carbon dioxide production is not detectable at room temperature, where all carbon is adsorbed and only water is formed, but increases to reach a constant level above 475 K. For temperatures above 400 K the licking coefficient is close to unity and there is no blocking due to preadsorbed oxygen (as there is for H2). Both the water and carbon dioxide formations are of Langmuir-Hinshelwood type but while the H2O desorption rate is found to depend only on impinging hydrocarbon flux the CO2 desorption rate depends also on the oxygen coverage.
44.	Dannetun, Helen, 1957-, et al. (författare) The H2-O2 reaction on palladium studied over a large pressure range : Independence of the microscopic sticking coefficients on surface condition 1985 Ingår i: Surface Science. - : Elsevier BV. - 0039-6028 .- 1879-2758. ; 152/153, s. 559- Tidskriftsartikel (refereegranskat)abstract We have studied the H2---O2 reaction on Pd over a large pressure range by letting the reaction take place on the Pd gate of a Pd-MOS structure. By measuring shifts in the capacitance versus voltage (C(V)) curve of the structure, the variation of the “free” hydrogen atom concentration can be monitored during the reaction. By combining these results with surface potential measurements and with photoelectron spectroscopy, we find a critical ratio of 0.4 where the surface turns from being oxygen dominated to being hydrogen dominated. The critical ratio is independent of the absolute pressures and of surface condition and shows no significant temperature dependence in the temperature range 50–200°C. This implies that hydrogen and oxygen have similar sticking coefficients at both clean and technical Pd surfaces. The conclusion is drawn that hydrogen (and oxygen) dissociation on Pd is a property of the Pd atom or cluster of Pd atoms and is not critically dependent on any long-range order parameter such as the surface electronic density of states.
45.	Dannetun, Helen, 1957-, et al. (författare) The study of alcohol induced hydrogen permeation in a catalytic membrane reactor 1996 Ingår i: Surface Science. - : Elsevier BV. - 0039-6028 .- 1879-2758. ; 357, s. 804-808 Tidskriftsartikel (refereegranskat)abstract We have studied dehydrogenation and subsequent permeation of hydrogen from some small alcohols and hydrocarbons over a 20 μm thin Pd membrane at temperatures between 523 and 623 K. It is only for the smaller alcohols that significant amounts of hydrogen permeate the membrane. An addition of oxygen in the alcohol supply is needed to prevent a slow quenching of the permeation. The ratio of oxygen to alcohol is critical. For the right balance between methanol and oxygen permeation is very effective, and comparable to permeation caused by pure hydrogen. Studies of CH3OD and C2H5OD further show that the permeation is dependent on the hydrogen origin, i.e. the methyl and hydroxyl hydrogen have different reaction pathways and permeation probabilities.
46.	Edwards, NV, et al. (författare) Real-time assessment of selected surface preparation regimens for 4H-SiC surfaces using spectroscopic ellipsometry 2000 Ingår i: Surface Science. - : Elsevier. - 0039-6028 .- 1879-2758. ; 464:1, s. L703-L707 Tidskriftsartikel (refereegranskat)abstract Spectroscopic ellipsometry (SE) was used to assess the removal of overlayer material from 4H-SiC (0001) and (0001) [Si- and C-face] surfaces in real time and, in particular, the critical final step of an otherwise standard RCA cleaning regimen commonly used to prepare SiC surfaces for contact formation. The treatments selected [buffered hydrofluoric acid (HF), concentrated HF, and dilute HF] removed 4-40 Angstrom of effective SiO2 overlayer thickness from these surfaces. The concentrated HF treatment yielded the best surface, i.e. that with the most abrupt transition region between bulk and surface and with the most oxide material removed. A fourth treatment regimen (sequential application of methanol, water, and 5% HF in methanol) was also developed for comparison with the full RCA clean. (C) 2000 Elsevier Science B.V. All rights reserved.
47.	Eriksson, Mats, 1963-, et al. (författare) Spillover of hydrogen, oxygen and carbon monoxide in oxidation reactions on SiO2 supported Pd 1994 Ingår i: Surface Science. - : Elsevier BV. - 0039-6028 .- 1879-2758. ; 311:1-2, s. 139-152 Tidskriftsartikel (refereegranskat)abstract Oxidation of H2 and CO on large, oxygen preexposed Pd islands supported on SiO2, has been investigated in the temperature range 323 ⩽, T ⩽ 523 K. The results have been compared with the corresponding reactions on a polycrystalline Pd film. A maximum reactive sticking coefficient of 0.9 for H2 and an initial sticking coefficient for O2 of 0.8 on both structures is concluded. The maximum reactive sticking coefficient for CO is 0.85 on the film and apparently larger than unity on the island structure. The results obtained from the island structure can be rationalized if O2 and H2 dissociate on the Pd islands and have the possibility to spillover onto the oxide, while CO adsorbs and reacts both on the Pd islands and on the oxide. Spillover of oxygen occurs in a precursor state and is irreversible with an apparent activation energy of 0.1 eV for the forward reaction.
48.	Eriksson, Mats, 1963-, et al. (författare) The catalytic oxidation of CO on polycrystalline Pd: Experiments and kinetic modelling 1998 Ingår i: Surface Science. - 0039-6028 .- 1879-2758. ; 412/413, s. 430-440 Tidskriftsartikel (refereegranskat)abstract The catalytic oxidation of CO on a thin, polycrystalline Pd film has been studied. Even though the Pd film is expected to be dominated by (111) facets, some distinct differences compared to single crystalline Pd(111) are observed. A kinetic model for the CO oxidation reaction is presented. It gives good agreement with experiments, both in terms of CO2 reaction probability and CO coverage during reaction conditions. The model assumes a random distribution of the adsorbates, an activation energy for the reaction that decreases with increasing CO coverage, as well as a CO sticking coefficient that in a temperature dependent fashion depends on the oxygen coverage. Single crystal data available from the literature (initial sticking coefficients and heats of adsorption) were mainly used as input parameters. Thus, the model might also be a useful starting point when modeling the catalytic oxidation of CO on single crystal surfaces.
49.	Fahlman, Mats, et al. (författare) Surfaces and interfaces in polymer-based electronics 2002 Ingår i: Surface Science. - 0039-6028 .- 1879-2758. ; 500:1-3, s. 904-922 Tidskriftsartikel (refereegranskat)abstract Research on electronics applications such as light-emitting devices for flat-panel displays, transistors, sensors and even solid state lasers based on conducting polymers is presently under way and in some cases has reached the stage of prototype production. The mechanisms for charge injection and conduction in these materials are being studied, as are the physics of luminescence and its quenching. Lately, research into controlling film morphology through self-organizing techniques also has gained interest. Though the present interest in conducting polymers mainly concerns the pristine semiconducting state, doped conducting polymers are also studied for potential use in many applications. In this paper, we present an overview of some of the central issues in surface and interface science in the field, as well as provide our view on what may lie ahead in the future. Specifically, the importance of metal/polymer, polymer/metal and polymer/polymer interfaces is addressed. We illustrate these using polymer-based light-emitting devices, though the same type of issues appear in other polymer-based applications such as transistors and solar cells. © 2001 Elsevier Science B.V. All rights reserved.
50.	Fornander, H., et al. (författare) A comparison of the CO and D2 oxidation reactions on Pd supported on MgO(100), MgO(110) and MgO(111) 1999 Ingår i: Surface Science. - 0039-6028 .- 1879-2758. ; 440:3, s. 375-386 Tidskriftsartikel (refereegranskat)abstract Oxidation of D2 and CO on oxygen pre-exposed 200 nm thick Pd films, epitaxially grown on MgO(100), MgO(110) and MgO(111), has been investigated in the temperature range 100–300°C. Oxygen initial sticking coefficients have been determined to be close to 1 for the 100 and 110 films, and around 0.8 for the 111 film. The sticking coefficient and reactive sticking coefficient for CO oxidation on Pd/MgO(100) is also close to 1, and the maximum reactive sticking coefficient for hydrogen oxidation is determined to be around 0.9 at temperatures above 200°C. It is shown that the reactivities for the different surfaces vary strongly with surface and oxygen coverage, and the consequence of this for supported particle catalysts is pointed out.

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