Issue Number 26

GAS SURFACE NEWS

December 1999

Editors Note GSDList and Thank you to all those who replied to the survey earlier this year on the Web Page future of Gas-Surface News. We have received enough support to suggest that publishing on the Web would be viable so this is the last issue posted This issue of the out to the entire address list. We will continue with the policy of asking Newsletter is also available Institutes to pay subscriptions so that all in that Institute who are interested on the Web site. To test may have access to GSNews at no extra charge. This policy also allows your ability to read and very small groups and individuals who are not part of a group, to receive the download check Newsletter free. In order to spread the costs fairly, however, it is still http://www.phchem.uni- important to increase our subscriptions base. We hope more Institutes will be able to pay, we will increase the subscription from £50 to £60 (first essen.de/gsd/ You will increase in 4 years) and we will take efforts to reduce our costs. On the need Adobe Acrobat back page you will find a list of all the Institutes already paying annual Reader (you can download subscriptions. If your own institute is not amongst them, you are asked to this free from the Adobe consider whether they could be added. If the list is not extended, we will be Web site Ð Version 4 is unable to cover our costs. preferable)).

As part of this increased efficiency I propose to completely re-draw the Gas-Surface Dynamics address list and GSDList (Email Server). After 9 years there are many Email Server - available to addresses that are no longer correct. EVERYONE is asked to complete the all those on the Gas- REPLY SLIP ON THE BACK PAGE and return it (via post or email) to myself. If you do not have access to the Web, please remember to tick the Surface News Mailing list. box to receive a copy by post. Just send your message to [email protected] I look forward to hearing from you all and meanwhile Ð enjoy this issue and essen.de. please invite any new members of your group to join the mailing list. The next issue is planned for early April. (Continued on back page....)

I N S I D E T H I S I S S U E 2 Research Reports- Leiden Inst of Chemistry, University of Leiden (Mischa Bonn, Prof. Dr Aart Kleyn) 4 Current Research - L.I.S.E. Facultés Universitaires Notre-Dame de la Paix in Namur (Petra Rudolf) 9 Meeting Reports 15 Papers for Publication 17 Job Vacancies and Announcements 23 Diary Page 24 Continuation from Page 1 and Reply Slip Ð EVERYONE MUST REPLY TO CONTINUE SUBSCRIPTION

EditorÐSue Free. Cambridge University Chemistry Dept, Lensfield Road, Cambridge, CB2 1EW, UK. Tel/Fax +44 1223 336536. [email protected]. Web Page containing contact list and other announcements Ð http://www.phchem.uni-essen.de/gsd/ Gas-Surface News

Research Report

Very Small and Very Fast: Studies of Surface Structure and Dynamics Leiden Institute of Chemistry, Leiden University P.O. Box 9502, 2300 RA LEIDEN The Netherlands

With the move of Aart Kleyn from the FOM- the reaction is taking place. In these so-called Institute in Amsterdam to head the “Surface and pump-probe experiments, one femtosecond laser Catalysis” Group at the Leiden Institute of pulse (pump pulse) is used to switch the reaction Chemistry in Leiden, the scope of the research on, and a second (the probe pulse) is used to there has broadened considerably. It was, of investigate changes in the electronic absorption course, quite broad to begin with: Ben spectrum: The products exhibit different absorption Nieuwenhuys has supervised, for many years, a lines from the reactants, and the transition from one group doing research focused on both supported to the other can be observed. Interestingly, one catalysts, -real catalysts in reactors -and on surface makes use of the finite speed of light in such science investigations on model catalytic systems. experiments: the probe pulse is guided over a mirror Present topics include "non-linear processes on that can be moved back and forth. Increasing the surfaces, STM investigations of multicomponent path length of the probe pulse by 1 µm causes a surfaces and catalytic oxidation reactions on delay of 3.33 fs (speed of light: c = 3x108 m/s), so multicomponent catalysts. A recent overview was that spectroscopic images of the system can be presented in GSN 18 {April 1997}. Aart is now taken at pre-selected times, simply by moving that further introducing molecular beams into the mirror back and forth. The beautiful experiments by Leiden Group. Zewail and co-workers not only identified transition states and reaction intermediates for model What is more, with Aart’s arrival in Leiden, an reactions, but also clarified the mechanism for some amplified femtosecond (1 fs = 10-15 s) laser important chemical reactions. These experiments system, which was being used in Leiden for the were all carried out in the gas phase, in pulsed study of ultrafast processes in liquids, became molecular beams. available for experiments on surfaces due to the retirement of a senior staff member of a When one wants to transfer the same techniques to neighboring group. Aart then asked the investigate the dynamics of reactions at surfaces, undersigned, at that time working as a post-doc in there are a few complicating factors. First of all, one the group of Martin Wolf with Prof. Ertl at the has to get a UHV system leak-tight and Fritz-Haber-Institute in Berlin, to join his group in characterization equipment operative and Leiden to set up a new experiment to investigate simultaneously get the femtosecond laser system to the dynamics of surface reactions directly by work. Anyone who has worked in either surface means of time-resolved surface spectroscopy. I science or optics knows that to get one going is hard have already been working on that type of enough. Recent years, however, have seen a steady experiment in Berlin. increase in the reliability of commercial laser systems, and indeed, there have recently been Ahmed Zewail, at the California Institute of several studies successfully combining the two. Technology recently won the Nobel in Chemistry for his ground-breaking work using femtosecond A second complication is that the electronic levels lasers to investigate chemical reaction dynamics. are strongly smeared, shifted and broadened, when Zewail and co-workers were the first to a molecule or atom is close to a metal surface. This demonstrate the possibility of real-time is caused by the strong electronic coupling between monitoring the reactants turning into products as the electrons of the molecules on the surface and the

Page - 2 - Gas-Surface News metal electron gas. The absence of well-defined (UCLA, Berkeley) for conventional (not time- resonances makes it hard to investigate such a resolved) SFG spectroscopy.[4] Time-resolved SFG system using electronic transitions in the visible or could provide an additional wealth of information UV to probe the reaction dynamics. A third on catalytic systems under reactive conditions. complication arises when one realizes that a monolayer of molecules at the surface is hard to We have a few vacancies for PhD students and detect optically, since it is optically very thin. The post-docs for this project. Those who are interested optical thickness of a system is defined as the should contact us. absorption cross section per sample unit length multiplied by the sample thickness. It is Mischa Bonn impossible to see changes in absorption due to the reaction when one sees no absorption to begin Leiden Institute of Chemistry with because there is only one layer of molecules. Leiden University P.O. Box 9502 The latter two problems can be overcome by the 2300 RA LEIDEN very elegant technique of time-resolved Sum- The Netherland Frequency-Generation (tr-SFG). The technique of [email protected] tr-SFG is essentially femtosecond RAIRS (Reflection Absorption InfraRed Spectroscopy): It allows one to record the vibrational spectrum of [1] J.A. Prybyla, H.W.K. Tom and G.D. Aumiller, adsorbates with very high sensitivity (signals from Phys. Rev. Lett. 68, 503 (1992). coverages below 10-3 monolayers of CO have [2] M. Bonn, S. Funk, Ch. Hess, D. N. Denzler, C. been observed) and very high time resolution Stampfl, M. Scheffler, M. Wolf and G. Ertl, Science (~100 fs). In analogy to the Zewail experiments, 285, 1042 (1999). the surface reaction is switched on by a pump [3] A. Bandara, J. Kubota, K. Onda, A. Wada, S.S. pulse, and the time evolution of the adsorbate is Kano, K. Domen and C. Hirose, J. Phys. Chem. B followed by means of time-resolved SFG. If we 102, 5951 (1998). take the desorption of NO from Ru(0001) as an [4] X. Su, P.S. Cremer, Y.R. Shen and G.A. example of a simple surface reaction, we know Somorjai, Phys. Rev. Lett. 68, 503 (1992). that the frequency of the N-O stretch vibration will change from 1825 cm-1 at the surface to 1876 cm-1 in the gas-phase. The temporal evolution of the vibrational frequency will give us information on how long it takes for molecules to desorb, after excitation of the substrate. It has already been demonstrated that important information on reaction dynamics and energy flow at surfaces can be obtained from such experiments [1, 2], specifically with time-resolved (in that case: picosecond) SFG [3]. In Leiden, we initially plan to study simple, elementary surface reactions, such as the desorption of NO from a metal surface. It should be noted, however, that this research is not limited to UHV: A very interesting trait of SFG is that, in contrast to RAIRS, it is specifically surface- sensitive. The vibrational signal can come from the surface only, so that the signal remains uninfluenced by gas in front of the surface. It is therefore very well-suited for the study of (prototype) metal catalysts under ambient pressures and/or reactive conditions. This has been demonstrated recently by Somorjai and Shen

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Laboratoire Interdisciplinaire de Spectroscopy Electronique, (LISE)

Facultés Universitaires Notre-Dame de la Paix, Rue de Bruxelles 61, B-5000 Namur, Belgium By Petra Rudolf The group of currently 2 Ph.D. students (Ingrid Marenne and Francesca Cecchet), 3 postdoctoral researchers (Annette Wingen, Celine De Nadaï and Caroline Whelan), and a lecturer (Petra Rudolf) is involved the study of the vibrational and electronic properties of new carbon-based materials such as and carbon nanotubes and of of supramolecular assemblies such as catenanes and rotaxanes. We have become an all-female group only very recently, when Charles-André Fustin and Michael R. C. Hunt finished their respective Ph.D and postdoctoral researcher appointments. We are part of a rather large laboratory, the Laboratoire Interdisciplinaire de Spectroscopy Electronique or LISE, consisting of four professors, two in physics and two in chemistry, five permanent scientific staff, 4 technical staff, 7 postdoctoral researchers, 9 phd students and a variable number of graduate students.

Introduction on the LISE conductor/ ceramic /organic layer combinations are explored. Capitalising on 25 years experience with electron spectroscopies (XPS-ESCA, HREELS, AES, Most techniques available at the LISE are electron UPS, and synchrotron radiation), and electron spectroscopies. Recently added techniques are diffraction, the LISE's research projects cover the STM/AFM (UHV), FT-IR, FT-Raman and UV- preparation, modification and characterisation of Vis spectroscopies. An important new surfaces and interfaces. Some fundamental goals development at the LISE in the past two years was are the determination of elemental composition the set-up of an electrochemistry laboratory. and crystallographic structure of the surface, the identification of the chemical bonds, the In addition, the LISE is active in designing and concentration profiles of elements at an interface, building electron spectrometers (MilliScan and and the composition maps at a surface (with a CDEELS). Furthermore integrated systems have lateral resolution of 10 µm). been built for fabrication, treatment and analysis of materials under UHV conditions (Integrated Many research projects carried out at the LISE, UHV Thin Films System, Plasma Treatment which I do not detail here, are chosen in view of Device, etc.). Moreover, several softwares have possible future applications, and some also been developed for instrument control, data comprise the behaviour of surfaces or thin films acquisition and data treatment. under laser, ion and plasma irradiation. Particular emphasis is laid on microelectronics The LISE is a member of the Institute for Studies (semiconductors, superlattices, including in Interface Sciences (ISIS) of the FUNDP and superconductors and heterostructures), structural many international networks, and is involved in materials (ceramics, polymers, including carbon joint research projects with other laboratories in fibres, composites and biopolymers), and catalysts academia and industry. (car exhaust cleanup). The LISE specialises in the preparation and characterisation of interfaces The large concentration of people working in the between these materials and typical metal/ semi- ISIS, both theoretically and experimentally, and

Page Number - 4 - Gas-Surface News the great variety of analytical tools available make groups the interested reader is referred to the LISE Namur an exciting place to do Surface Science. WebPages For further information on activities of the other http://www.fundp.ac.be/~lise .

Figure 1: C1s photoemission spectra for

1 ML C60 on Ni(110), Pt(111) and

Ag(111) and for a thick C60 film deposited on Ni(110). The right panel shows an enlargement of the shake-up region for the same samples

Research on Fullerenes Depending on the system in question, the increases in the C 1s width above that of the The study of interactions between fullerenes and multilayer in principle reflect the following surfaces has developed into a major area of re- effects: C atomic sites with significantly different search on this third allotropic form of carbon. Two environments; creation of electron-hole pairs; aspects motivate this interest: firstly, from a coupling to the charge carrier plasmon. The latter technological point of view, the substrate-induced two are dominant in cases involving significant modification of the electronic and structural charge transfer, such as C60/Ag(111), for which properties of C60 layers is an important question to EELS data show a high intensity of low-energy be addressed if this new material is to find an electronic excitations and the charge carrier application in the electronics industry. Secondly, plasmon at 0.9 eV. We note that in the C 1s the variety of both bond strength and bond lineshape the coupling to the charge carrier character observed in the interaction between C60 plasmon is difficult to resolve. Typical for the and a substrate is exceptional and still far from covalently bound MLs in which little or no charge being completely understood from a fundamental transfer occurs (such as C60/Pt(111) shown here) point of view. The bond which this molecule are narrow C 1s lines. This observation tends to forms with a substrate can be of very weak van rule out a significant role for inequivalent C sites, der Waals type on surfaces such as for example which can be tentatively explained by the very GeS,i or result in a very strong charge transfer of efficient intramolecular screening of local charges. up to 11 electrons/molecule when adsorbed on K A further source of information is the shake-up multilayers.ii On all metallic surfaces investigated structure, blown up in the right panel of Fig. 1. so far,iii,iv fullerenes are chemisorbed, but the This structure corresponds to coreionised final degree of hybridisation of the C60 molecular states in which a valence electron is promoted orbitals with the substrate electronic states and the from an occupied to an unoccupied level and is amount of charge transfer differs greatly from therefore similar to a convolution of the occupied substrate to substrate as illustrated also by the C1s and unoccupied parts of the valence band. The photoemission spectra shown in figure 1. broadening of the shake-up structures in the other

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ML films can be regarded as a measure for the Cu(100) reveal that a non-IR active mode bonding interaction with the substrate. becomes active upon adsorption and that its frequency shifts proportionally to the charge These changes brought upon the electronic transferred from the metal to the molecule by structure of the molecule by adsorption have about 5cm-1 per electron. Additionally, as shown important consequences for the thermal stability in figure 2, the adsorption is accompanied by a of adsorbed fullerenes.v, vi While all coverages on broadband reflectance change which is interpreted top of the first physical monolayer of C60 do not as due to the scattering of conduction electrons of interact with the substrate and therefore all start to the metal surface by the adsorbate. The reflectance desorb at about 455 K, the first layer can either change allows the determination of the friction desorb at slightly higher temperature as on coefficient of the C60 molecules which is rather Ag(111), or decompose as on Pt(111) or Ni(110) small (corresponding to an inverse lifetime of the in a kinetically limited process. We have shown frustrated translation of the adsorbate due to that this destruction occurs via conversion of a creation of electron-hole pairs τ ~ 102 ps), relatively weakly bound state arising from room consistent with a marked metallic character of the temperature adsorption into a strongly bound state adsorbed molecules. in competition with . Currently we are exploring the interaction of het-

Molecular desorption. On Mo(110) a progression erofullerenes such as C59N and of endofullerenes through 4 distinct chemisorbed states is observed, such as Sc2@C84 with metal surfaces. from weakly bound through the immediate precursor to fragmentation, with increasing hybridisation between molecule and substrate.vi Research on Catenanes and Rotaxanes In recent years, new synthetic developments have made possible the preparation of molecules with non trivial architectures and topologies. Catenanes in which two macrocycles are threaded like the rings of a chain and rotaxanes in which a macrocycle is threaded onto a bar with stoppers at both ends, by right belong to this arena and have been the focus of a concerted effort carried out by many important laboratories world wide. The fundamental question arising from the newly acquired synthetic capabilities is whether these species, either as a class or individually, can have an impact in the real world as parts of devices whose design and construction would not be Figure 2: Infrared spectra in the 400-2500 cm-1 region of a accomplished without their exploitation. Several

Cu(100) surface collected during C60 deposition at room of the interlocked structures prepared so far can temperature. A broadband reflectance change as well as one indeed change the relative positions of their -1 absorption band at 1440 cm are clearly seen. component parts under external stimulus: the macrocycles of the catenane can circumrotate one Another very interesting aspect of surface science another like the rings of a macroscopic chain, the with fullerenes is a surprisingly rich scenario for macrocycle of a rotaxane can change position the vibrational dynamics of chemisorbed C60. Our along the bar and this adds a degree of freedom Infrared spectroscopy studies with synchrotron not available to other systems. To date elegant and vii radiation of C60 on Ag(111), Au(110) and incisive work has been performed with the intent

Page Number - 6 - Gas-Surface News of characterising various types of catenanes and states over the many chromophores of the rotaxanes. However, in its near totality, it was catenane can occur. carried out in solution and only a very small fraction of effort was concerned with the solid From there we moved on to the thin-film growth state properties. In our work we try to bridge he of this catenane. The molecules were deposited fundamental gap due to the lack of solid state onto gold single crystals by sublimation under characterisation, which is the first mandatory step UHV or by dipping the substrate into a solution of towards real applications. The molecules we work the catenane. Sublimation yielded well-ordered on are synthesised by D. A. Leigh and his group at films (albeit with domain diameters of only about the Centre for Supramolecular and 100 Å) while dipping produced only disordered Macromolecular Chemistry of the University of films.x The vibrational spectra acquired by Warwick, U.K.. For the interpretation of our HREELS indicated that the first layer of catenanes results we closely collaborate with F. Zerbetto and is chemisorbed. This result, confirmed by XPS his group at the Department of Chemistry ‘G. data,xi implies that the macrocycles are immo- Ciamician’ of the University of Bologna, Italy bilized on the surface and that the “mechanical who carry out theoretical studies on these systems. bond” which holds them together is no longer dynamic. We started out with the characterisation of the vibrational properties of the simplest benzylic Of interest for possible applicational aspects is amide [2] catenane by infrared spectroscopyviii: the therefore the development of techniques to grow very nature of the molecule - in which several two dimensional ordered arrays of catenanes and similar groups interact either via bonds or via rotaxanes such that these molecules are still able space - results in a system with a high sensitivity to move. In a recent study we report our first to the environment which is typical of the attempts in this directionxii: the characterisation of catenane only and is not present in the parent thiol-terminated catenane and rotaxane thin films macrocycle. We then carried out studies of the self-assembled from the liquid phase on Au(111) low-lying electronic states of the same moleculeix using HREELS and XPS. The HREELS study giving support to the theoretical picture which shown in figure 3 has revealed shows that partial delocalisation of the electronic

Figure 3: HREELS spectra collected θ θ in specular ( i = r = 45¡) and off- θ θ specular ( i = 45¡, r = 25¡) scattering geometries at a primary beam energy of 6.0 eV from thiol- terminated GlyGly rotaxane, GlyGly thread and benzylic amide [2]catenane (a) adsorbed at 300 K on Au(111) and (b) following annealing of the layers for 45, 45 and 120 minutes at ~500 K, respectively. Typical energy resolution of the elastic peak was 80-160 cm-1 in terms of the full width half maximum.

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the absence of a preferred molecular orientation indicates the formation of larger domains with a for rotaxane and catenane adlayers at room chemisorption via the carbonyl on the gold surface temperature which can be explained by the in the case of rotaxane and catenane. Variations in complex structure of such molecules. Only the sulfur 2p signal intensities revealed molecular catenane which is di-thiol terminated seems to rearrangement resulting in a tilt of the molecules, form some domains but without any long range favoured by partial desorption, to the extent that a order. XPS results have confirmed the occurrence flat-lying configuration becomes probable. Based of thiolate formation for each molecule. Self- on these first results, the catenane looks promising assembly of di-thiol terminated catenane follow- for the development of novel self-assembled ing 14 hours immersion results in the formation of monolayers in contrast with the rotaxane. Further a monolayer of molecules oriented principally experiments are in progress in order to determine parallel, as obtained in case of sublimated the optimum experimental conditions to obtain catenane on gold, and not perpendicular to the more ordered monolayers. surface. The study of the effects of annealing

REFERENCES i G. Gensterblum, K. Hevesi, B. Y. Han, L. M. Yu, J.-J. Pireaux, P. A. Thiry, R. Caudano, A. A. Lucas, D. Bernaerts, S. Amelincks, G.VanTendeloo, G.Bendele, T.Buslaps, R.L.Johnson, M.Foss, R.Feidenhans’l and G.Le Lay., “Growth mode and electronic structure of the epitaxial C60(111)/GeS(001) interface”, Phys. Rev. B50 (1994) 11981. ii A. J. Maxwell, P. A. Brühwiler, S. Andersson, N. Mårtensson, and P. Rudolf, “Electronic Structure of KXC60 compounds with x>6”, Chem. Phys. Lett. 247 (1995) 257. iii P. Rudolf, M. Golden, and P. A. Brühwiler, "Studies of Fullerenes by the Excitation, Emission, and Scattering of Electrons", J. Elect. Spec. and Rel. Phen. 100 (1999) 409. iv P. Rudolf, " C60 adsorption on metal surfaces" invited review paper in Electronic Properties of Novel Materials: Fullerenes and Nanostructures, eds. H. Kuzmany, J. Fink, M. Mehring, and S. Roth, World Scientific Publishing Co. Ltd., Singapore (1996) p.263. v M. Pedio, K. Hevesi, N. Zema, M. Capozi, P. Perfetti, R. Gouttebaron, J.-J. Pireaux, R. Caudano and P. Rudolf, " C60/metal surfaces: Adsorption and Decomposition", Surf. Sci. 437 (1999) 249. vi M. R. C. Hunt, A. Rajogopal, R. Caudano and P. Rudolf, "Temperature-dependent chemisorption of C60 on Mo(110): Precursors to cage destruction", Surf. Sci., in press. vii P. Dumas, M. Hein, A. Otto, B. N. J. Persson, P. Rudolf, R. Raval and G. P. Williams, "Friction of molecules on metallic surfaces: experimental approach using synchrotron infrared spectroscopy", Surf. Sci. 433-435 (1999) 797. viii M. Fanti, C. A. Fustin, D. A. Leigh, A. Murphy, P. Rudolf, R. Caudano, R. Zamboni and F. Zerbetto, "The high-frequency vibrations of the simplest benzylic amide [2]catenane", J. Phys. Chem. A109 (1998) 5782-5788. ix A. M. Brouwer, W. J. Buma, R. Caudano, M. Fanti, C.-A. Fustin, D. A. Leigh, A. Murphy, P. Rudolf, F. Zerbetto, J. M. Zwier, "Experimental and theoretical studies of the low-lying electronic states of the simplest benzylic amide [2]catenane", Chem. Phys. 238 (1998) 421. x C. A. Fustin, P. Rudolf, A. F. Taminiaux, F. Zerbetto, D. A. Leigh and R. Caudano,"Growth and Characterisation of Benzylic Amide [2]Catenane Thin Films", Thin Solid Films 327-329 (1998) 321. xi C. A. Fustin, R. Gouttebaron, P. Rudolf, F. Zerbetto, D. A. Leigh, and R. Caudano, "Photoemission Study of Benzylic Amide [2]Catenane Films, Influence of Potassium Intercalation", submitted. xii C. De Nadaï, C. M. Whelan, C. Perollier, G. Clarkson, D. A. Leigh, R. Caudano and P. Rudolf, "The self-assembly of mechanically interlocked and threaded rings: A HREELS and XPS study of thiol-functionalised catenane and rotaxane molecules on Au(111) ", Surf. Sci. in press.

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Meeting Report Ð Euro-Conference

“Elementary steps in fast catalytic oxidation reactions” Hotel Mercure, Lelystad, Flevoland, NL - October 2-6 1999

Heterogeneous catalysis is of great importance for the town Lelystad, a town built 30 years ago in the 'polder' (petro) chemical industry. Practically all the chemical Flevoland. Flevoland is the youngest part of the processes are steered by catalysts. Most of the Netherlands and covers 225000 ha of new land which industrially used catalysts have been developed via was part of the 'Zuiderzee'. empirical knowledge and 'trial and error' experiments during the past 80 years. More stringent environmental Organizing committee: legislations or the demand for a more efficient use of the feedstock continuously requires improved/new Bernard Nieuwenhuys (Leiden), chairman catalysts. This, however, is not an easy task, since Gert-Jan Kramer (Shell, Amsterdam) heterogeneously catalysed reactions are extremely Bernd Riedmuller (Amolf, Amsterdam) complex. Basic research is needed to develop taylor- Corine de Wolf (Leiden) made catalysts. Dave King and Sue Free (Cambridge) Hella Knegtel (Leiden) In the past 20 years, our basic insight into gas-surface interactions has improved tremendously. This insight Total number of participants: 36 (7 women, and 29 has been obtained by the study of well defined model men), 8 with the Netherlands nationality, 7 with the systems. The complexity of these model systems has German, 5 Greek, 3 British, 3 Italian, 3 Spanish, 2 increased, thus decreasing the gap between surface Danish, 1 Belgium, 1 Swedish, 1 Irish, 1 Finnish and 1 science and industrial catalysis. It is, therefore, with the Czech nationality. The Eu funds available for anticipated that in the coming decade the role of this meeting were put to good use subsidizing most of surface science in the development of heterogeneous the expenses for travel and accommodation for 26 catalysis will become more important. young scientists and, partly for 8 senior invited speakers.

Topics of the conference: a) Fundamental studies on Report adsorption and reactions on surfaces related to oxidation catalysis.b) Oxidation catalysis. Surface science studies have provided a wealth of information on the elementary steps in catalytic The subject of this workshop was 'elementary steps reactions. However, as was nicely shown by Robert in fast catalytic oxidation reactions'. Much research Schlögl (FHI/Berlin) for partial oxidation reactions over is done to improve existing (for example, ethene Cu and Ag, the active site cannot always be represented epoxidation) and to develop new processes (for by single crystal model catalysts. Metastable structures example, catalytic conversion of methane to synthesis containing the ’active site’ are formed under catalytic gas). In addition to partial oxidation reactions, total reaction conditions. catalytic oxidation is of great importance to protection of the environment (for example, automotive catalysis). Ben Nieuwenhuys (Leiden) started with a brief Much fundamental research on the dynamics of related introduction on the topic of catalytic oxidation reactions systems is done in Europe at several universities and on noble metal and transition metal oxide catalysts. The national laboratories. major part of his talk dealt with the question ‘how can the performance of a noble metal catalyst in low The purpose of the workshop was to stimulate temperature oxidation be improved’? It was shown that contacts between researchers in the fields of surface the combination of a noble metal with a transition metal science and applied heterogeneous catalysis. oxide, in particular CuOx and MnOx, can yield very active catalysts. Peter Thormählen (Göteborg) showed that

Venue: Hotel Mercure Lelystad, located in the new catalysts based on Pt and CoOx, although exhibiting a

Page Number - 9 - Gas-Surface News very high activity in the individual reactions, deactivate catalysis. Norbert Kruse (Brussels) discussed the under real reaction conditions (Automotive catalysis). formation of long chain alcohols from syngas over Co Another lecture dealing with noble metal-transition based catalystys. In addition, the formation of nickel metal oxide catalyst was presented by Bart carbonyl over various Ni surfaces was discussed. The

Zwijnenburg (Delft). It is a challenge to develop a adsorption and dissociation of C2N2 on Rh(110) was process for the direct oxidation of propene to propene discussed by Federica Bondino (Trieste). Luca Rumiz epoxide. Bart showed that the epoxide is formed with (Trieste) discussed the adsorption of CO on Rh(111) on low yield but high selectivity from propene and H2 + O2 the basis of time-resolved XPS studies with emphasis on over Au/TiO2 catalystys. Ruud Grisel (Leiden) the population of CO adsorbed on atop and hollow sites. presented another talk dealing with oxidation reactions over Au-metal oxide catalysts: a comparison of the A large number of talks were focused on the catalytic behaviour of these catalysts in CO and CH4 oxidation. partial oxidation (CPO) of methane. Bernd Riedmuller (Amsterdam) discussed the dissociative adsorption of Phil Davies (Cardiff) presented STM results of O and N methane on the stepped Pt(533) surface Gert Jan on Cu surfaces: formation of O + N islands, ‘mobile’ Kramer (Shell/Amsterdam) presented a nice overview of Cu-O chains which ‘lock’ the surface preventing the present knowledge on CPO. Carlo de Smet expansion of the lattice needed for formation of (Eindhoven) discussed O assisted subsurface O. O2 adsorption and dissociation on silver surfaces was the main topic of Aart Kleyn’s lecture CH4 dissociation and presented results of kinetic (Leiden). The possible presence of physically modelling of CPO on a Pt gauze catalyst in the presence adsorbed O2 and its relation to the weakly of transport phenomena. Ib Chorkendorff (Lyngby) chemisorbed O2 (precursor for oxygen dissociation) discussed in detail the collaborative research of the were discussed. Costas Vayenas and Dimitros Danish team concerning the elementary steps in Tsiplakides (Patras) discussed the origin of methane activation: molecular beam studies, STM and electrochemical promotion in catalysis and showed calculations. many examples of electrochemical promotion in adsorption and catalytic reactions on metal surfaces: An excursion to the Shell and Technology Centre in ethene oxidation to the epoxide and aldehyde. Thomas Amsterdam was organized by Gert Jan Kramer: an Bär (Brussels) discussed the mechanism of NO overview of research at Shell and a tour showing decomposition on silver and showed nice FIM images experimental facilities. Herman Kuipers presented a illustrating NO-induced structural changes of silver tips. lecture on “New prospects for technology in Shell: CPO, FIM was also used by Thierry Visart de Bocarme fuel cells and the hydrogen future." (Brussels) to examine the catalytic oxygen-hydrogen reaction on Rh. Alessandro Baraldi (Trieste) discussed Overall this meeting represented the state of the art in the information that surface core level shifts can the subject elementary steps in fast catalytic oxidation. provide on the first step of oxidation reactions: The attempt to bring together surface scientists, adsorption of oxygen. In particular the adsorption of theoreticians and catalysis scientists was a great oxygen on Rh and Ru surfaces were discussed. success and resulted in lively discussions. Angelos Michaelides (Belfast) showed that DFT can be used to predict the catalytic reaction pathways for hydrogenation of C (CH, CH2, CH3, and CH4) and N Ben Nieuwenhuys, chairman (NH, NH2, NH3) and the reversed reactions. Leiden University Leiden Institute of Chemistry Results of DFT slab calculations were also presented P.O.Box 9502 by David King (Cambridge) for Co (1010) + CO + K. 2300 RA Leiden/The Netherlands On the basis of these results a new model was email: [email protected] proposed for promoter action in heterogeneous

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Reactive Surfaces Symposium - 9-10th September 1999

Report by Stephen Jenkins (Department of Chemistry, Cambridge)

If a man may be judged by the quality of his friends, then surely a scientist must be judged by the quality of his students, colleagues and collaborators. On the evidence of the attendance list for Professor David King's 60th birthday symposium on the 9th and 10th of September, his reputation as one of the world's leading surface scientists will be secure for many years to come.

Organised by one of Dave's former students, Professor Mike Bowker, the “Reactive Surfaces” meeting brought to Cambridge a selection of delegates that would put many an international conference to shame; all linked by the fact that at some point or other their careers overlapped with Dave's. From Norman Sheppard, who gave Dave his first lecturing job at the University of East Anglia in the late 60s, to the post-grads and post-docs of his current research group, it seemed everybody had an anecdote to reveal, if not a colleague to embarrass.

The lectures themselves were an enlightening cross-section of surface science at the end of the 20th century, with such notables as John Yates and Bob Madix contribuing keynote addresses; the latter putting in an appearance as the elusive mystery guest. Perhaps unsurprisingly, the King & Wells method for measuring sticking probability was consistently identified by many speakers as one of Dave's most outstanding and enduring contributions to the field. Unfortunately, pace precludes a more detailed report on the scientific content of a very varied and stimulating meeting.

Varied and stimulating would also be apt descriptions of the reception and dinner at Downing College, of which Dave is Master. The occasion brought a much appreciated opportunity for Dave's colleagues, past and present, to catch up on old friendships. For many in his current research group there was also the novelty of matching names known only from article by-lines to actual faces.

And so to the final day, on which Dietrich Menzel and Richard Lambert gave the keynote speeches. In the end, however, the only appropriate way to draw a meeting like this to a close was with a speech from the man himself, and Dave duly obliged, wishing mainly to emphasise that the event should certainly not be seen as a swan-song. Watch this space....

The “Reactive Surfaces” conference was sponsored by BP International, Elsevier Science, ICI Technology, Johnson Matthey, Omicron Surface Science, Unilver Research and Vacuum Generators.

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European Research Conference on Electronic Structure of Solids and Surfaces: Challenges in predictive descriptions of reaction dynamics and growth properties at surfaces Lenggries (Bavaria), Germany, 18-23 September 1999

Chairperson: Axel Gross (TU Munich,) Vice-Chairpersons: Gianfranco Pacchioni (University of Milan) Thorsten Kluener (FHI Berlin)

The theoretical description of reactions and (Queen's University, Kingston, Canada) growth properties at surfaces is an important discussed the construction of non-local research field owing to its fundamental aspects as exchange-correlation functionals. In the well as its technological relevance. For a construction of these functionals there is still predictive description of processes at surfaces some variational freedom, a fact that was also the reliable determination of the interaction of pointed out later in the conference by Bjork atoms and molecules with surfaces is a Hammer (Aalborg University, Denmark). Axel prerequisite. Due to the improvement of electronic Becke prefers to use this freedom to adjust a structure theory algorithms and the increase in small set of variational parameters in order to computer speed in the last years there has been reproduce a set of known results, but there are tremendous progress in mapping out whole other schools of thought that avoid to use any potential energy surfaces for these processes. adjustable parameters. Furthermore, the The main goal of this conference was therefore to extension of DFT to treat polarizabilities and bring together experts in the field of electronic excited states is of strong current interest. Two structure theory calculations with theoreticians possible methods, time-dependent who work in the field of reaction dynamics and density functional theory and the GW growth processes at surfaces. More approximation were presented by Evert Jan specifically, the aim was to review the current Baerends (Vrije Universiteit Amsterdam, The status of the field and to inspire fruitful Netherlands) and Rex Godby (University of York, collaborations between these two groups of UK), respectively. Although these methods can scientists which used to be rather separate in the be quite successful for small systems, the past. Equally important for the theoretical determination of electronically excited states for treatment of processes at surfaces is the close extended systems still represents a considerable contact to the experiment. Hence another challenge. significant aspect of this conference was the participation of experimentalists working in this DFT calculations only provide the potential field. energy for a set of discrete configurations. In dynamical simulations, however, a continuous To set the stage, the conference was opened with representation of the potential energy surface a session on fundamental aspects of electronic (PES) is needed. The talks of Doug structure calculations and density functional Doren (University of Delaware, USA) and Horia theory (DFT). The reliability of DFT calculations is Metiu (University of California at Santa Barbara, mainly determined by the accurate treatment of USA) were concerned with schemes for the the many-body effects. Axel D. Becke interpolation of ab initio energies. A neural

Page Number - 12 - Gas-Surface News network model for inter-atomic interactions was determined by the Free Energy which includes presented by Doug Doren, while Horia Metiu entropic effects and not just by the bare barrier introduced a directed genetic programming heights. This session was closed by the talk of scheme for finding the best analytical fit to a set Anne Chaka (Lubrizol Corp., USA) with the of given data. Both schemes are rather provocative title Quantum Mechanics and the successful in reproducing the PES for low- Automobile. She demonstrated that nowadays dimensional problems, however, their applicability DFT is already used by the chemical industry to for problems with a large number of freedoms illuminate the chemical processes underlying the (say, more than 10) still has to be proven. performance of lubricants and additives.

The sessions covering methods for the There is one main difference between chemical application of ab initio data to simulate processes reactions at surfaces and in the gas phase: at on surfaces were opened by Geert-Jan Kroes surfaces energy can be very efficiently dissipated (Leiden University, The Netherlands). He showed by excitation of phonons or electron-hole pairs that the benchmark system for the activated while in the gas phase there are usually no dissociation of molecules at surface - hydrogen dissipation channels open. However, the on copper - can now be treated in a detailed theoretical treatment of dissipation, in particular manner by six-dimensional quantum within a quantum mechanical framework, still dynamics methods using a PES derived from represents a major computational challenge. Two DFT calculations. These calculations allow a complimentary approachs were discussed by quantitative comparison with experiment so that Ronnie Kosloff (Hebrew University, Jerusalem, also the accuracy of the DFT-derived PES can be Israel) and Shiwu Gao (Chalmers University, checked. Didier Lemoine (Universite de Lille, Gothenborg, Sweden). Ronnie Kosloff introduced France) demonstrated the importance of the high- a finite surrogate Hamiltonian to generate the true dimensionality in the simulation of scattering short time dynamics of a primary system coupled processes by showing that the so-called to a bath. Using the resurfacing of hydrogen to a supernumerary rotational rainbows which appear Ni surface he demonstrated the applicability of in low-dimensional simulation of NO this approach if the temperatures are not too scattering from Ag(111) disappear if also the large and the time scales are not too long. Shiwu surface corrugation is considered. Gao, on the other hand, presented a dissipative quantum dynamics method within the reduced density matrix formalism. This method, which can The first talk in the session about growth and deal with high temperatures but is still restricted etching, corrosion and lubrication was given by to low dimensions, was applied to the Harald Brune (EPF Lausanne, Switzerland). He photoinduced reaction of oxygen on Pt(111). An reviewed the field of STM experiments to study alternative approach to determine reaction rates nucleation and growth on homogeneous and in thermal equilibrium situations was presented by inhomogeneous substrates. Due to the atomic Hannes Jonnson (University of Washington, resolution of the STM, these experiments can Seattle, USA). He focused on quantum transition yield a detailed information about the microscopic state theory in terms of Feynman path integrals processes, in particular if the experiments are and its application to hydrogen dissociative combined with ab initio calculations. The adsorption. theoretical treatment of atomic growth processes was the topic of the talk by Talat Rahman (Kansas State University, USA). She stressed the As already mentioned above, the determination of importance of finite temperature effects in the electronically excited states still represents a simulation of growth processes. For many major challenge. But equally challenging is the systems the fact what are the most favourable inclusion of electronic transitions in the simulation processes at a certain surface temperature is of reaction dynamics. The semiclassical treatment

Page Number - 13 - Gas-Surface News of electronic transitions in molecular dynamics simulations was the topic of the talk by John Tully The talks were supplemented by two poster (Yale University, New Haven, CT, USA), while sessions. All posters were introduced by a three- Peter Saalfrank (University College London, UK) minute, one-slide presentation which was well presented a quantum mechanical description of received. The conference was closed by desorption processes induced by electronic concluding remarks of Volker Heine transitions. The semiclassical treatment can (Cavendish Laboratory, Cambridge, UK). He easily be extended to higher dimensions emphasized the tremedous progress that but treats the electronic transition only in an has been made in the last years in DFT approximative manner. The quantum mechanical calculations as far as the size of the systems that description, on the other hand, can treat the can be treated is concerned. This was especially electronic transition properly, but is still limited to reflected in the posters that were presented at the low dimensions. The contact to experiment in this conference. DFT calculations have become an session was provided by Katharina Al-Shamery indispensable tool in the theoretical treatment of (University Oldenburg, Germany) who gave a reaction dynamics and growth processes at detailed report on laser induced desorption surfaces. Still there are many open problems, in experiments from oxide surfaces. particular in the treatment of electronically excited states, as was demonstrated in this conference. In this field the experimentalists are far ahead of Dave King (University of Cambridge, UK) the theoreticians. presented molecular beam experiments of important catalytic processes on Pt surfaces. He also emphasized the important role that DFT Overall it seems that bringing together experts calculations can play in combination with from different fields at this conference was quite a experimental results for a microscopic success. The nice atmosphere in the Arabella understanding of these processes. This was Brauneck Hotel in Lenggries which allowed many furthermore demonstrated in the talk by Notker relaxed and informal scientific discussions Roesch (Technical University Munich, Germany) certainly contributed to this success. The who focused on oxide supported metal species excursion to Munich was also an excellent investigated by DFT calculations using the cluster opportunity to get to know each other, in some approach to represent the surface. Bjork Hammer cases with unexpected results. Last but not least, (Aalborg University, Denmark) showed that the the smooth preparation of the conference by the reactivity at stepped surface can be enhanced EURESCO staff in Strasbourg, in particular dramatically compared to flat surfaces. He Rhona Heywood, was very important for the demonstrated how this enhanced reactivity can success of the meeting. Hopefully many be understood microscopically by carefully fruitful collaborations will originate from this analyzing DFT results. As already conference. Since DFT calculations represent mentioned above, he also pointed out that there such a versatile tool to investigate microscopic is an intrinsic uncertainty in the construction of the details in the interaction of atoms, molecules and exchange-correlation functional in the generalized solids, it is desirable that the EURESCO series gradient approximation which can lead to Electronic Structure will be continued in the changes of up to 0.3 eV in the barrier heights of future, probably visiting other fields like biological the reactions he considered. The last talk of the systems, coherent control or semiconductor conference was given by Mario Rocca (University technology, just to name a few. of Genova, Italy) who showed experimentally how complicated the seemingly simple system oxygen on Ag(100) can be.

Page Number - 14 - Gas-Surface News

Papers for Publication

• VI Pazzi, P Philipsen, EJ Baerends, GF • SB Darling, AT Hanbicki, TP Pearl and SJ Tantardini: "Oxygen Adsorption on Ag(110): Sibener: “Rational Design of Interfacial DFT Band Structure Calculations and Structure: Adsorbate-Mediated Templating”, Dynamical Simulations", Surf. Sci. (in press) J. Phys. Chem. B (in press) • O Krauth, G Fahsold, N Magg and A Pucci: • TP Pearl and SJ Sibener: “Proximity Heater "Anomalous infrared transmission of for the Elevated Temperature In Situ Vacuum adsorbates on ultrathin metal films: Fano Scanning Tunneling Microscopy of Metal effect at the percolation threshold", Phys. Rev. Surfaces,“ Rev. Sci. Instrum. (in press) Lett. (submitted) • AT Hanbicki, SB Darling, DJ Gaspar and SJ. • G Fahsold, A Bartel, O Krauth, N Magg and Sibener: “Influence of Steps on the Interaction A Pucci: "IR-optical properties of ultrathin Fe Between Adsorbed Hydrogen Atoms and a films on MgO(001) beyond the percolation Nickel Surface”, J. Chem. Phys. (in press) threshold", Phys. Rev. B (submitted) • Wei Li, MJ Stirniman and SJ Sibener: “The • G Fahsold, A Priebe, N Magg and A Pucci: Effect of Cluster Formation on Mass "An IR-Transmission Spectroscopical Study Separation in Binary Molecular Beams,” J. of the Influence of Substrate Surface Defects Chem. Phys. (submitted) on the Morphology and the Electronic • ME Viste, KD Gibson and SJ Sibener: Structure of Ultrathin Fe Grown on “Heterogeneous Combustion of Benzene on MgO(001)", Thin Solid Films (submitted) Rh(111): Kinetics and Dynamics of CO And • G Fahsold, G König, A Pucci and K-H Rieder: CO2 Production”, J. of Catalysis (submitted - "Growth of Fe on MgO(001) studied by 1999). Helium-atom scattering," Phys. Rev B • J Hahm and SJ Sibener: “Cylinder Alignment (submitted) in Annular Structures of Microphase • VI Pazzi, PHT Philipsen, EJ Baerends and GF Separated Polystyrene-B-Polymethylmeth- Tantardini: “Oxygen adsorption on Ag(110): acrylate,” Submitted as a Letter to Langmuir DFT band structure calculations and (1999) dynamical simulations,” Surf. Sci. (in press) • L Diekhöner, A Baurichter, H Mortensen and • KD Gibson, M Viste, EC Sanchez and SJ AC Luntz: “Observations of metastable Sibener: "Physical and Chemical Properties of atomic nitrogen adsorbed on Ru(0001),” High-Density Atomic Oxygen Overlayers J. Chem. Pbys. (submitted) Under UHV Conditions: (1x1)-O/Rh(111)," J. • M Casagrande, S Lacombe, L Guillemot and Chem. Phys. (in press) VA Esaulov: “Electron transfer processes in • KD Gibson, JI Colonell and SJ Sibener: “The the interaction of fluorine with a chlorine

Decomposition of NO2 on Rh(111): Product covered Ag(111) surface,” Surf. Sci. (in NO Velocity And Angular Intensity press) Distributions” Surf. Sci. (in press) • M Casagrande, S Lacombe, L Guillemot and • JA Slezak, BD Zion and SJ Sibener: VA Esaulov: “On ISS and chlorine adsorption “Enhanced Oxidation Rate of Ni(111) by on silver,” Surf. Sci. (in press) Atomic Oxygen,” Surf. Sci. Lett. (in press)

Page Number - 15 - Gas-Surface News

• L Guillemot, S Lacombe and VA Esaulov chemisorption - Specific adsorption on step “Time dependent characteristics of electron defect sites on Pt surfaces”, (submitted) tunnelling processes in H-, O- and F- • M Mavrikakis, P Stoltze and JK N¿rskov: formation on Ag(111),” NIM B (submitted) “Making gold less noble”, (submitted) • B Hellsing, J. Carlsson, L Walldén and • RM Watwe, HS Bengaard, JR Rostrup- SÅ Lindgren "Phonon-induced decay of a Nielsen, JA Dumesic and JK N¿rskov: quantum-well hole: 1 ML Na on Cu(111)", “Theoretical studies of stability and reactivity Phys Rev. B (in press) of CHx species on Ni(111)”, (submitted) • L. Lous, L Österlund and B. Hellsing: • C Bendtsen, OH Nielsen and LB Hansen: "Electron Structure and Kinetics of K on “Solving large nonlinear generalized ," J. Chem. Phys. (submitted). eigenvalue problems from Density Functional • J Carlsson and B Hellsing, "First principles Theory calculations in parallel,” (submitted) investigation of the quantum well system Na • LS Byskov, JK N¿rskov, BS Clausen and H on Cu(111)", Phys. Rev. B (submitted) Topsøe: “H2 activation on a transition metal • HS. Bengaard, I Alstrup, I Chorkendorff, S sulfide - The role of flexibility”, (submitted) Ullmann, J.R Rostrup-Nielsen and JK • S Helveg, JV Lauritsen, E Lægsgaard, I Nørskov: “Chemisorption of methane on Stensgaard, JK N¿rskov, BS Clausen, H Ni(100) and Ni(111) surfaces withpreadsorbed Topsøe and F Besenbacher: “The atomic-scale potassium”, J. Catal. (accepted) structure of single-layer MoS2 nano-clusters,” • T Rasmussen, T Vegge, T Leffers, (submitted) OB Pedersen and KW Jacobsen: "Simulation • L. Österlund, M Pedersen, I Stensgaard, E of structure and annihilation of screw Lægsgaard and F Besenbacher: “Quantitative dislocation dipoles," Phil. Mag. A (accepted) determination of adsorbate-adsorbate • J Schiøtz and T Vegge: “Computer interactions,” (submitted) simulations of the mechanical properties of • L Petersen, L Bürgi, H Brune, F.Besenbacher metals," Science Progress (accepted) and K Kern: Comment on "Observation of • JH Larsen and I Chorkendorff: “From two-dimensional Fermi contour of a fundamental studies of reactivity on single reconstructed Au(111) surface using Fourier crystals to the design of catalysts,” Surf. Sci. transform scanning tunneling microscopy" by Rep. (accepted) D Fujita, K Amemiya, T Yakabe, H Nejoh, T • J Nerlov, S Sckerl, J Wambach and I Sato and M Iwatsuki [Surf.Sci 423, 160 (1999)], (submitted) Chorkendorff: “Methanol synthesis from CO2, • CO, and H2 over Cu(100) and Cu(100) TR Linderoth, S Horch, L Petersen, S Helveg, modified by Ni and Co”, J. Appl. Cat A M. Schønning, E Lægsgaard, I Stensgaard and (accepted) F Besenbacher: “Energetics and dynamics of • Morgenstern, E Lægsgaard, I Stensgaard, F Pt dimers on Pt(110)-(1x2),” (submitted) Besenbacher, M Böhringer, R Berndt, F • K H¿jrup Hansen, T Worren, S Stempel, E Mauri, A de Vita, R Car and W-D Schneider: Lægsgaard, M Bäumer, H-J Freund, F “Stability of two-dimensional nanostructures,“ Besenbacher and I Stensgaard: “Palladium

J. Appl. Phys. (accepted) nano-crystals on Al2O3: Structure and • CE Tripa, TS Zubkov, JT Yates, M adhesion energy,” (submitted) • Mavrikakis and JK Nørskov: “Molecular N2 L Petersen, B Schaefer, E Lægsgaard, I Stensgaard and F Besenbacher: “Imaging the

Page Number - 16 - Gas-Surface News

surface Fermi contour on Cu(110) with STM,” of liquid surfaces”, Phys. Chem. Com.m (submitted) (submitted) • L Petersen, F Besenbacher and EW Plummer: • S Wright and E Hasselbrink: “Photochemistry “Determining the surface Fermi contour: of disilane adsorbed on an H terminated Fourier transform STM,” (submitted) Si(100) surface,” J. Chem. Phys. (in press) • TH Rod, A Logadottir and JK N¿rskov: • H Arnolds, C Rehbein, G Roberts, RJ Levis “Ammonia synthesis at low temperatures,” and DA King “Femtosecond Near-Infrared (submitted) Laser Desorption of Multilayer Benzene on Pt{111}: Spatial Origin of Hyperthermal • G Papoian, JK N¿rskov and R Hoffmann: “A Desorption,” Chem. Phys. Lett. (in press) comparative theoretical study of the hydrogen and ethyl chemisorption on the Pt(111) • SJ Jenkins and DA King: "Polarisation surface,” (submitted) Promotes Fischer-Tropsch Catalysis,” (submitted) • S Dahl, J Sehested, CJH Jacobsen, E • A V Walker and DA King: “A Molecular Törnqvist and I Chorkendorff: “Surface Beam Study of Methane Dissociative science based microkinetic analysis of Adsorption on Oxygen Precovered Pt{110} ammonia synthesis over ruthenium catalysts”, (1x2),” Surf. Sci. (in press) on the Pt(111) surface," (submitted) • AV Walker and DA King: “The Reaction of • S Dahl, E Törnqvist and I Chorkendorff: Gaseous Oxygen with Adsorbed Carbon on Pt{110} (1x2)”, J. Chem. Phys. (in press) “Dissociative adsorption of N2 on Ru(0001): A surface reaction totally dominated by • WA Brown and DA King: “NO steps,” (submitted) Chemisorption and Reactions on Metal Surfaces: a New Perspective”, J. Phys. Chem. • C Westphal, S Dreiner, M Schuermann, H (submitted) Zacharias: “Holographic reconstruction of • CI Carlisle, DA King, M-L Bocquet, J Cerd Si(111) atom positions from energy- and and P Sautet: “Imaging the Surface and the angle-resolved photoelectron diffraction,” Interface Atoms of an Oxide Film on Ag{111} Surf. Sci. (submitted) by STM: Experiment and Theory”, (submitted) • C Menzel, H Zacharias: “The internal energy of small ammonia clusters in a supersonic • SJ Jenkins and DA King: “Pentaprismane and beam and after scattering off LiF(100),” Hypostrophene from First-principles, with Plane Waves”, Chem. Phys. Lett. (submitted) European Physical Journal D, (submitted) • • Q Ge, SJ Jenkins and DA King: “Surface A.W. Kleyn: “Probing the dynamics of Magnetic Localisation at the Atomic Scale,” chemisorption though scattering and sticking (submitted) in molecular beams,” ed. R. Campargue. Springer Verlag (submitted) • B Berenbak, B Riedmüller, DA Butler, CT Rettner, D.J. Auerbach, S Stolte and AW Kleyn.: “Molecular Beam Study on Interaction Dynamics in a Reactive System: NO on Bare Ru(0001),” Phys. Chem. Chem. Phys. (submitted) • MA Gleeson, J Lourenco, AMC Moutinho, J Los and AW Kleyn: “Ion sputtering as a probe

Page Number - 17 - Gas-Surface News

Job Vacancies

POSTDOCTORAL POSITIONS - Technical University of Denmark

Atomic scale simulations of materials, surfaces and biomolecules Two postdoctoral positions will be available at the Center for Atomic-scale Materials Physics (CAMP) at the Technical University of Denmark from winter/spring 2000 or later. One position is in the area of atomic scale simulations of materials processes using molecular dynamics and density functional methods. The other position is in the area of density functional calculations and modeling of surface chemical and enzymatic processes.

The positions are for two years. The monthly salary is in the range dkr 23.500 - dkr 25.500 (US$ 3600-3900) depending upon qualifications.

Further questions can be addressed to: Professor Jens K. N¿rskov ([email protected]) or Professor Karsten W. Jacobsen ([email protected]) Applications including a CV, publication list and names of three references should be sent as soon as possible to: Helle Wellejus - e-mail: [email protected]

Address: CAMP, Department of Physics, DTU, Building 307, DK-2800 Kongens Lyngby, Denmark More information about the center can be found at: http://www.fysik.dtu.dk

POSTDOCTORAL POSITIONS - Department of Chemistry University of Cambridge Postdoctoral positions are available in Dave King’s group, for an experimental surface scientist with uhv experience. The succesful candidates could work on a novel 4K STM coupled to a pulsed laser system and a molecular beam doser, or our dual supersonic molecular beam scattering system for studies of catalytic mechanisms, or our newest instrument, a fibre-optic LEED instrument for low current, low temperature quantitative structural studies.

Interested candidates should contact Dave King at [email protected]; fax +44(0) 1223 762829; phone +44 (0) 1223 336338

Page Number - 18 - Gas-Surface News

POSTDOCTORAL POSTION

University of Erlangen-Nürnberg,

A Postdoc position in surface science is available at the Institute of Physical Chemistry in the group of Prof. Hans- Peter Steinrueck. The research program of the group focuses on the electronic and geometric structure of bimetallic surfaces and the characterization of their catalytic activity using model reactions. The goal is to obtain very detailed information by using a variety of experimental techniques that include STM, XPS, ARUPS, IV-LEED, TPD and molecular beam methods. Experience in at least one of these techniques is therefore required. Possible research areas are: (1) Electron spectroscopic studies using synchrotron radiation at BESSY-II in Berlin or at MAX- II in Lund, (2) development of a new photoelectron spectrometer for in-situ studies of surface reactions using synchrotron radiation, and (3) investigations of the surface morphology of ultrathin metals layers using variable temperature scanning tunneling microscopy.

Candidates with a PhD in physics or physical chemistry who are interested in joining an interdisciplinary research team should contact:

Prof. Dr. Hans-Peter Steinrück Tel:. (09131) 85-27343, Sekr. (09131) 85-27342 Institut für Physikalische und Theoretische Chemie Fax: (09131) 85-28867 Universität Erlangen-Nürnberg Email: [email protected] Egerlandstrasse 3, D-91058 Erlangen, Germany http://www.chemie.uni-erlangen.de/pc2

2 - POSTDOCTORAL POSITIONS

TMR Network in “Surface Photochemistry” University of Essen and University of Liverpool

Candidates are invited to apply for post-doctoral positions to work in the EU funded TMR network "Surface Photochemistry". Applicants, who will be below 35 years old, should have a PhD in Chemistry or Physics and should be from an EU member state other than Germany (for Essen) or Britain (for Liverpool). The positions are available at the University Essen and the University of Liverpool and the contracts are negotiable from 1 to 3 years.

Further information may be obtained from

http://www.phchem.uni-essen.de/TMR/

Page Number - 19 - Gas-Surface News

PH.D and POSTDOC POSITIONS Ð University of Leiden

A number of positions are available. For further information contact

Dr Mischa Bonn Ð [email protected] Professor Dr Aart Kleyn Ð [email protected] Dr Ben Niewenhuys Ð [email protected]

Leiden Institute of Chemistry - Gorlaeus Labs/Leiden University, PO Box 9502 - 2300 RA Leiden- NL

Femtosecond surface reaction dynamics

1 PhD or post-doc position for the work on ultrafast reaction dynamics with femtosecond lasers. The succesful applicant will employ femtosecond infrared surface spectroscopy to gain important insights into elementary processes at simple liquid surfaces. Collaborations include a.o. dr. Huib Bakker (Amsterdam), and theoretical support from dr. G.J. Kroes (Leiden). - For information, contact: dr. Mischa Bonn.

1 PhD or post-doc position for work on ultrafast reaction dynamics with femtosecond lasers in UHV. This project involves the study of the timescales of elementary reaction steps of simple reactants on metal surfaces. This project is a joint effort with dr. Martin Wolf (Berlin).- For information, contact: dr. Mischa Bonn.

Surface photochemistry

2 PhD or post-doc positions for work on surface photochemistry. The aim of this project is to shed more light on the photochemical reactions that take place at metal and ice surfaces using experimental methods from the fields of basic surface science, physical chemistry and molecular physics. There are several projects running on these topics using two surface science apparatus that share a large collection of lasers with nanosecond until femtosecond pulse duration. - For information, contact: prof. dr. Aart W. Kleyn.

Molecular beams

1 PhD or post-doc position for work on molecular beams. The research will involve molecular beam scattering with state specific detection of product molecules, and femtosecond pump-probe spectroscopy. Contact: prof. dr. Aart W. Kleyn.

Catalysis

1 PhD or post-doc position is available for research of noble metal-transition metal oxide surfaces (STW), in collaboration with prof. dr. A. Bliek (Amsterdam) and prof. dr. J.W.M. Frenken (Leiden). Contact: dr. Ben E. Nieuwenhuys.

1 PhD or post-doc position is available for research in the field of oscillatory behavior of surfaces of surface reactions (NRSC-Catalysis), in collaboration with prof. dr. R.A. van Santen (Eindhoven). For information, contact: dr. Ben E. Nieuwenhuys

Page Number - 20 - Gas-Surface News

Meeting Announcements

19th International Conference on Atomic Collisions in Solids ICACS-19

Paris, France - 29 July - 3 August 2001

ICACS is a biannual meeting, which deals with physical and chemical phenomena induced by the interaction of low and high energy beams of charged or neutral particles with matter: surface and bulk of solids, liquids and biomaterials. The most recent meetings have been held in Odense (Denmark, 1999) and Beijing (China, 1997).

The objectives of the Paris ICACS-19 are to assess the state of the art in the current understanding of a variety of phenomena such as energy losses of ions, radiation damage, sputtering, excitation, ionisation and electron emission as well as collision induced reactions and desorption of charged or neutral atomic and molecular species. Fundamental aspects of electron transfer in particle surface/bulk interactions will be highlighted. While the programme will focus mainly on the interaction of atomic, molecular and cluster projectiles, related processes induced by electron, positron and photon beams, will also be considered. Pertinent materials are pristine or adsorbate covered metals, semiconductors, insulators, as well as polymers, bio-materials and liquids. Macro to nano structures of these materials will be considered. New developments in experimental techniques may be presented.

The emphasis of the meeting is on fundamental processes, but challenging scientific and technological applications in physics, chemistry, biology and medicine will be considered. The programme will consist of oral and poster presentations and sufficient time for informal discussions will be allocated.

Contact : Vladimir A.Esaulov,

Laboratoire des Collisions Atomiques et Moleculaires

bat.351, Universite de Paris Sud

91405 Orsay Cedex

France

phone : (33)1 69 15 76 80 - fax : (33) 169 15 76 71 e-mail: [email protected] http://veof1.lcam.u-psud.fr/idc/icacs19.html

Page Number - 21 - Gas-Surface News

JVC-8 8th JOINT VACUUM CONFERENCE of Croatia, Austria, Hungary and Slovenia 4-9 June 2000 - Pula, Croatia

Organized by the Croatian Vacuum Society with the sponsorship of IUVSTA and Ministry of Science and Technology of Croatia

Scope of the conference: Reporting results of original scientific work in the fields of • Applied Surface Science, • Surface Science, • Electronic Materials • Thin Film • Nanometer Structures, • Vacuum Metallurgy, • Plasma Science and Technique, • Vacuum Science This will be achieved through plenary and invited lectures, oral and poster contributions.

International Organizing Committee: Milorad Milun (conference chairman), - Gyorgy Radnoczi, Hungary, - Herwig Bangert, Austria,- Milko Jaksic, Croatia, - Sandor Bohatka, Hungary, - Ognjen Milat, Croatia, - Manfred Leisch, Austria - Andrej Pregelj, Slovenia Ð Nikola Radic, Croatia, - Vinko Nemanic, Slovenia

International Programme Committee: Nikola Radic (chairman), - Milorad Milun, Croatia, - Rudolf Dobrozemsky, Austria, - Petar Pervan, Croatia, - Monika Jenko, Slovenia, - Branko Pivac, Croatia, - Tivadar Lohner, Hungary, - Herbert Stoeri, Austria, - Vladimir Matolin, Bohemia, - Tamas Szoereny, Hungary, - Marian Vesely, Slovakia, - Anton Zalar, Slovenia

List of plenary lecturers: • Alessandro Borghesi, Universita degli Studi di Milano-Bicocca, Italy • Peter D. Johnson, Brookhaven National Laboratory, USA • Yves Pauleau, L'Institut National Polytechnique de Grenoble, France • Boris Sinkovic, Physics Department, University of Connecticut, USA • Klaus Wandelt, Institute of Physical and Theoretical Chemistry, University Bonn, Germany

There will be also 14 invited speakers whose names will be announced soon.

Conference language: - English Conference venue: The conference will take place in a modern hotel Histria located 5 km from the Pula downtown on a small peninsula Punta Verudela (buses commute every 15 minutes). Beaches surround the hotel on its three sides. Two swimming pools are located right in the hotel. Numerous tennis courts, yacht clubs and other sporting facilities offer a wide palette of opportunities to have a great time during the conference free time. For those who would like to see more of this beautiful piece of land a number of excursions will be organized daily to various popular sites. Pula is an old town with many historical sites and an ancient history.

Pula may be reached by car, bus, train, airplane and ship.

Important dates: Abstract deadline: 1st March 2000 Advanced registration: 1st May 2000

FURTHER INFORMATION http://faust.irb.hr/~jvc8/ contains all relevant information regarding the Conference, Contact address details ÐSee DIARY PAGE

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Diary Page

6th March 2000 Astrophysical Chemistry Group/Royal Astonomical Society, Young Researchers Meeting, London. A one-day meeting aimed primarily at PhD students and Postdocs. Further information at - http://www.nottingham.ac.uk/~pczhjf/astrochem.htm or Helen Fraser - [email protected]

April 3rd Ð 8th 2000 The Second San Luis Symposium on Surfaces, Interfaces and Catalysis, Mar del Plata (Conference and Summer School). Scholarships available for students from USA. Contacts: N. America: W Tysoe at [email protected], Latin America G. Zgrablich at [email protected], Europe: R Lambert - [email protected]. or surface.chem.uwm.edu/conference.html 30th May 2000- 3rd June 2000 8th International Conference on Theoretical Aspects of Heterogeneous Catalysis - CAT 2000, La Colle sur Loup, Alpes-Maritimes, France 30/05/2000 - 03/06/2000. further information from: [email protected]

JVC Ð 8th Joint Vacuum Conference or Croatia, Austria, Hungary and Slovenia, at Pula, Croatia. Organised by the Croatian Vacuum Society with the sponsoship of IUVSTA and Ministry of Science and Technology of Croatia. Conference Chair: M Milun, Institute of Physics, Zabgreb. Further information at - [email protected] or http://faust.irb.hr/~jvc8/ or fax: (+385) Ð1-4680399

10-14 July, 2000 Internatinoal Converence on Solid Films and Surfaces (ICSFS-10), Princeton University, USA. Preliminary information now avaiable on the web: http://www.pmi.princeton.edu/ICSFL/ Email: [email protected]

4-6th September 2000 Faraday Discussion 117 Ð Electron Excited States at Surfaces University of Nottingham, UK. Chairman: Professor S Holloway, (University of Liverpool, UK.) Further Information http://www.rsc.org/lap/confs/faradischome.htm

11th-15th September 2000 Adriatico Research Conference on Lasers in Surface Science, Trieste, Italy. Organisers H-J Freund, TF Heinz and H Zacharias. Further information available from: [email protected]

1st-5th October 2001 Ecasia ’01 9th European Conference on application so Surface and Interface Analysis. Maresilles France. Further Information is at [email protected] or http://www.enscp.jussieu.fr/ECASIA/

SUMMER 2001 Surface Science Summer School. Following the School in Dronten, Netherlands this summer, the next in the series will be held in READING, UK. Chair of Organising Committee: Mike Bowker. Further details to follow.

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