Giorgio Paolucci

Sincrotrone Trieste S.C.p.A.

The ID10 beamline of the SESAME (Synchrotron‐light for Experimental Science and Applications in the Middle East) synchrotron light source in Jordan was inaugurated in June 2023 and is now open to scientific users. The beamline, which was designed and installed within the European Horizon 2020 project BEAmline for Tomography at SESAME (BEATS), provi...

SESAME and a consortium of five Helmholtz Centers are designing and installing a state-of-the-art soft X-Ray undulator beamline at the SESAME light source in Amman, Jordan. Funding is provided by the Helmholtz Association over a four year project cycle that started in January 2019. This is an interim report covering the first 36 months of the proje...

XAFS/XRF is a general-purpose absorption spectroscopy beamline at the Synchrotron-light for Experimental Science and Applications in the Middle East (SESAME), Jordan. Herein, its optical layout is presented along with its powerful capabilities in collecting absorption and fluorescence spectra within a wide energy range (4.7–30 keV). The beamline is...

The Materials Science (MS) beam­line at SESAME (Synchrotron-light for Experimental Science and Applications in the Middle East), dedicated to the X-ray powder diffraction technique, started its operational phase in December 2020 by hosting its first users. The MS endstation comprises a two-circle diffractometer coupled with a PILATUS 300K area dete...

SESAME (Synchrotron-light for Experimental Science and Applications in the Middle East) is the only synchrotron light facility in the Middle East and neighboring regions, officially opened in 2017. Among the identification and construction of the first operational beamlines, infrared spectromicroscopy was selected as one of the two beamlines to be...

We present a detailed description of the SESAME Materials Science (MS) beamline for X-ray diffraction (XRD) applications, presently under construction in Allan, Jordan. The beamline is based on components previously installed at the Swiss Light Source, but modifications in the beamline design have been introduced to match the characteristics of the...

Elettra is one of the first 3rd-generation storage rings, recently upgraded to routinely operate in top-up mode at both 2.0 and 2.4 GeV. The facility hosts four dedicated beamlines for crystallography, two open to the users and two under construction, and expected to be ready for public use in 2015. In service since 1994, XRD1 is a general-purpose...

The third generation sources of soft X-rays, ALS and ELETTRA, have been producing data in surface and interface science for over two years. The impact of their ultrahigh brightness is quite evident, particularly as far as photoemission techniques are concerned. We illustrate this point with a short review of very recent examples from ELETTRA, in th...

From November 24–26, 2008, the annual Elettra Users Meeting was held at the International Centre for Theoretical Physics in Trieste. The event followed the now customary formula of two scientific workshops, each of just over a day, with the relatively brief Users Assembly between the two. This year's workshops focused on two important objectives of...

The electronic structure of semimagnetic (Cd, Mn) Te involves the Mn3d states which strongly affect disorder, localized correlations, and hybridization. The model introduced here is LCAO, itinerant and incorporates both chemical disorder and magnetic moment fluctuations. Its predictions, obtained using the CPA, are compared with extensive photoemis...

Spin-flip electronic transitions have been recently observed in ferromagnetic metals by electron energy loss spectroscopy (EELS) with spin analysis. The strong energy dependence of the exchange excitation process involved allows the identification of these transitions also by ordinary EELS by taking the ratio of spectra obtained with low energy and...

A unique approach of synthesizing the electric double layer at a metal-electrolyte interface under ultra-high vacuum conditions is briefly outlined. Results are presented of a study of water adsorption on clean Cu (110) using ultra-violet photoelectron spectroscopy (UPS), low energy electron diffraction (LEED), thermal desorption spectroscopy (TDS)...

A joint X-ray photoelectron spectroscopy (XPS) and near edge X-ray absorption fine structure (NEXAFS) investigation of the adsorption of phenylacetylene (PA, C6H5CCH) on the surface of Rh(100) single crystal was carried out by evaporating PA on the clean metal surface in the monolayer and multilayer regimes.The experimental results indicate that th...

The changes in the surface composition of a Pt(50)Rh(50)(100) alloy due to an ongoing 2H(2) + O(2)-->2H(2)O chemical reaction have been studied in situ. Exploiting the high-energy resolution and surface sensitivity of synchrotron radiation core-level spectroscopy it was possible to monitor the population of the two transitions metals atoms at the g...

The adsorption dynamics and geometry of phenylacetylene (PA) on Cu(100) was investigated by means of X-ray photoemission (XPS), near edge X-ray absorption (NEXAFS) spectroscopies and by quantum chemical calculations. The clean metal surface was exposed to PA vapors and the C1s core level spectrum evolution was monitored by means of time-resolved XP...

Macromolecular arrays containing Zn-diethynylporphyrin coordinated to platinum tethers were studied using near-edge X-ray absorption fine structure (NEXAFS) spectroscopy at the N K-edge. Porphin (Pf), 2,8,12,18-tetraethyl-5,15-diethynyl-3,7,13,17-tetramethylporphyrin (PfNH) and 2,8,12,18-tetraethyl-5,15-diethynyl-3,7,13,17-tetramethylporphyrinatozi...

The influence of potassium, in the submonolayer regime, on the adsorption and coadsorption of CO2 and H on a stepped copper surface, Cu(115), has been studied by photoelectron spectroscopy, temperature-programmed desorption, and work-function measurements. Based on the fast recording of C 1s and O 1s core-level spectra, the uptake of CO2 on K/Cu(11...

The experimental determination of the composition and structure of gas–solid surface interface at different stages of surface reactions is a crucial point in elucidating the reaction mechanism. This requires a quantitative surface sensitive technique, providing information on how the substrate surface, adsorbed species and their bonding configurati...

The nature of bonding in amorphous carbon nitride was studied with core level spectroscopies such as x-ray absorption, photoemission, and Auger electron spectroscopy, using synchrotron radiation as the excitation source. The changes in local structure were systematically studied as a function of sample preparation conditions. The correspondence bet...

A near‐edge x‐ray absorption fine structure (NEXAFS) spectroscopy investigation on the electronic structure of some novel π‐conjugated organometallic polymers is presented. The investigated materials consist of Pt and Pd(II) complex units linked together through σ‐bonded organic spacers of ethynyl‐thiophene type in a polymeric array. The C K‐edge N...

The local adsorption geometry of the low-coverage, short-range-ordered layer formed upon oxygen adsorption on the Rh(110) surface at 120 K has been quantitatively characterized by photoelectron diffraction measurements and multiple-scattering cluster calculations. The results of the structural analysis are compatible with a model where the oxygen a...

Using high resolution core level photoemission, we investigated the disordering transition of the fullerene molecules at the (111) surface of C (60) films. The experimental evidence of a two-step mechanism for the rotational disordering of surface fullerene molecules is provided. The data are consistent with a recent model in which the rotational d...

The mechanism of oxygen incorporation in Ag is still poorly known. As recently demonstrated [Phys. Rev. B 63 (2001) R1404], oxygen adatoms removal by CO oxidation leaves the Ag(001) surface in a modified state in which oxygen segregation from the bulk and the formation of a surface oxide phase can be induced by further CO exposure. Here we show tha...

The design and first tests of a new supersonic molecular beam are presented. The instrument is dedicated to study in a controlled way the interaction of atoms and molecules with solid surfaces in combination with high-resolution core level photoemission at the SuperESCA beamline of ELETTRA, the third-generation synchrotron radiation source in Tries...

We followed in real time the thermal reaction of fullerene molecules with the Si(111) surface by means of fast photoemission spectroscopy. The formation of SiC via C60 fragmentation on Si(111) is used as a key example of the capability of fast photoemission, associated with a fine temperature control, in determining the nature of thermally induced...

For the latest generation of SR sources, local bump orbit feedback systems are being developed for the improvement of the stability of the delivered radiation. The high brightness beamlines using undulator radiation are the most sensitive to electron beam oscillations. Therefore, Photon Beam Position Monitors (PBPM) are being built as detectors of...

Resonant photoemission from GdCu2 and Gd5Si4 has been investigated in the photon energy range of the Gd 4d→4f threshold. The emission from the valence Cu 3d and core Cu 3p and Si 2p levels has been studied to check the presence of the multiple atom resonance effect. The anti-resonance on the Cu 3d level has been observed, similar to the one observe...

We exploit the capabilities of photoelectron diffraction (PED) to provide quantitative information on the local structure of the first layers of clean and adsorbate-covered surface systems. Selected studies of low-energy PED are presented, highlighting the advantages of the angle-scanning approach. In the first experiment, we evaluate the clean Rh(...

The combination of new-undulator-based synchrotron radiation sources with state-of-the-art electron detection systems has allowed major improvements in the study of gas-surface interactions. In particular, the high photon flux, high energy resolution and high data acquisition speed have rendered it possible to use x-ray photoelectron spectroscopy (...

Core level and valence band photoemission spectroscopies show that, for an ordered C60 monolayer chemisorbed on Ag(100), metallic phases are formed at any Na doping level, following a rigid band filling behavior, until the conduction band is completely filled with 6 electrons/molecule. These observations, which contrast with the bulk phases behavio...

By means of synchrotron radiation photoemission spectroscopy, we have investigated the adsorption and desorption processes of the SO2 molecule on a rutile TiO2(110)-(1×1) surface. We have recorded the S2p core-level photoemission peaks for different SO2 exposures at a substrate temperature of 120 K in order to get information about the divers speci...

The temperature dependence of the surface resistivity for a metallic K(3)C(60) ordered film in the nonsuperconducting state has been obtained by reflection electron energy loss spectroscopy. We demonstrate that the normal state electronic and transport properties of the top molecular layer of K(3)C(60) are similar to the corresponding properties me...

High-resolution core-level photoemission measurements for ethyne (HCCH) and 2-butyne (H3C–CC–CH3) on the Ni(1 1 1) surface reveal the presence of vibrational excitations for both adsorbates, similar to those observed in recent gas-phase core-level photoemission investigations. The vibrational line splitting for ethyne is 300±50 meV (). A binding...

The Rh(110)-c(2×2)-CN phase has been examined by means of scanning tunneling microscopy (STM) and full dynamical low-energy electron diffraction (LEED). From STM large c(2×2) domains are observed. The detailed LEED-IV structural analysis indicates that CN is located in the grooves of the (110) surface, approximately atop second layer rhodium atoms....

The latest generation SR sources have severe constraints for the stability of the delivered radiation. The high brightness beamlines using undulator radiation are most sensitive to electron beam oscillations. Therefore, photon beam position monitors for undulator radiation are being built as detectors of beam movement and as references for feedback...

The photochemistry induced at 40 K by synchrotron radiation at 400 eV in CH4 molecules adsorbed on Pt(1 1 1) was studied by high resolution fast XPS. The photoreactions were monitored by acquiring the C1s core level spectrum as a function of time for methane adlayers with coverage ranging from submonolayer to multilayer regime. We have observed mol...

This paper reports an ultra-violet photoemmision spectroscopy study on K3C60 in the temperature range 30–600 K. The experiment shows that the temperature dependence of the conduction band is consistent with the behaviour of a strongly correlated metal. In addition, the photoemission intensity near the Fermi edge decreases as the temperature is incr...

Core level and valence band photoemission spectroscopies show that for an ordered single layer of C60 chemisorbed on a clean Ag(1 0 0) surface metallic phases are formed at any Na doping level, following a rigid band filling behaviour, until the conduction band is completely filled with 6 electrons/molecule. These observations, that contrast with t...

We have investigated the adsorption of the SO2 molecule on a TiO2(1 1 0) single crystal at a substrate temperature of 120 K by means of core level synchrotron radiation photoemission. By studying the S 2p and O 2s core level peaks, we show that from the first adsorption stages up to the saturation coverage, SO2 adsorbs molecularly on the TiO2(1 1 0...

High-resolution measurements are reported of the surface core-level shift (SCLS) of the 3d level for the Rh(111) surface as a function of oxygen coverage Θ on the surface. These measurements are analyzed by density-functional theory calculations of the initial- and final-state contributions to the shifts. The calculations are found to reproduce wel...

We have applied the tool of resonant photoemission at the L3 absorption edge to thin Mn layers deposited on Cu(100). This allows us to study the transition from atomic to solid-state phase by following the 3d-band formation through the localization of a photon-excited electron in the presence of a 2p core hole. We have observed localized behavior f...

Growing attention has been drawn in the past years to the \alpha-phase (1/3 monolayer) of Sn on Ge(111), which undergoes a transition from the low temperature (3x3) phase to the room temperature (\sqrt3 x \sqrt3)R30° one. On the basis of scanning tunnelling microscopy experiments, this transition was claimed to be the manifestation of a surface cha...

The dissociative oxygen chemisorption on the Ru(101¯0) surface has been studied by monitoring the changes of the O1s and Ru3d5/2 core levels and by measuring the evolution of the diffraction pattern during oxygen exposure at 270 K. The sensitivity of core level binding energies to different geometrical configurations, together with the measurements...

We show that in presence of subsurface oxygen, CO oxidation of oxygen precovered Ag(001) modifies the surface in such a way that CO adsorption is stabilized up to crystal temperatures of 160 K. When diffusion is activated new surface oxide phases form, characterized by oxygen both in surface and in subsurface sites and by a high density of states j...

A beamline for advanced dichroism (BACH), to perform light polarization dependent experiments in the 35–1600 eV photon energy range is under construction at the ELETTRA Synchrotron Radiation Source in Trieste, Italy. The radiation source, based on two APPLE-II helical undulators, is designed for high photon flux and high resolving powers. The photo...

The detection of the real photon beam trajectory as delivered to the users, by a third generation SR facility, is of paramount importance for the effectiveness of the most sensitive experimental measurements. Photon beam position monitors (PBPM) have been developed for this purpose. The most common is the so-called blade-type-monitor which is based...

The structure and magnetic properties of ultrathin Rh layers deposited on highly oriented pyrolitic graphite (HOPG) have been investigated by means of core-level photoemission and scanning tunneling microscopy. The Rh growth on HOPG follows the Volmer-Weber mode at 300 K for any coverage, while Rh may form a commensurate p(1×1) ordered structure wh...

The main features of a thermomodulation system have been singled out by analysing the thermal response of a bulk sample. Its dependence on the physical parameters of the system and on the external perturbation has been summarised in a series of curves. A high-efficiency arrangement suitable for measurements at room temperature is presented. The cri...

The normal state temperature dependence of a metallic K3C60 phase pure film has been investigated by means of core levels and valence band photoemission, carbon K edge x-ray absorption, and electron energy loss spectroscopies and compared with that of a Mott–Hubbard insulating K4C60 film. The anomalous temperature behavior of K3C60, in the range 30...

A beamline named BACH (Beamline for Advanced diCHroism), thought to perform light polarization dependent experiments like adsorption and photoemission spectroscopy as well as X-ray scattering, is under commissioning at the ELETTRA Synchrotron Radiation Source in Trieste, Italy. It will be based on a Padmore VASGM (Variable Angle SGM) monochromator...

The various components in the N 1s photoemission spectra of amorphous carbon nitride are identified by measuring their photon energy dependence and comparing the experimental results with ab initio multiple scattering calculations. The intensity modulations with photon energy are due to the extended x-ray absorption fine structure effects.

Spectroscopic investigations on the electronic structure of thin films of various Zn-porphyrinato/Pt assemblies, consisting of a Zn-porphyrinato (ZnPf) macrocycle inserted between bis(phosphine)platinum(II) centres, were carried out by means of synchrotron radiation-induced near-edge x-ray absorption fine structure (NEXAFS) spectroscopy at the thir...

In this letter we present a chemical shift photoelectron diffraction (CS-PED) study of the c(4×2) phase of CO on Pt(111), in which two molecular species are present. The angular dependence of both chemically shifted C1s core levels was independently determined in a high resolution photoemission experiment. By means of a full multiple scattering ana...

Oxygen adsorption on Ru(101̄0) is studied using the evolution of the 3d5/2 photoemission surface core-level shift as a function of coverage. We show that the measurements are sensitive to changes occurring to atoms in both the first and the second layer. This permits a direct demonstration that oxygen adsorbs on this surface in the three-fold hexag...

High-resolution synchrotron radiation photoemission has been used to investigate the formation of the Cu(110)+c(2×2)-Si surface alloy. The complex spectra of the Si2p core-level are analyzed as multiple component spectra for different Si coverages and annealing temperatures of the surface alloy. The results show that c(2×2) islands are formed from...

It is demonstrated that CO dissociates on a potassium-modified Cu(115) surface at 125 K. The dissociation process is conditioned by both the presence of steps and an alkali metal coverage in the range of 0.4<θK<1 ML. Carbonate is formed at 220 K via the Boudouard process CO+CO→CO2+C and reaction with oxygen. Further annealing to 470 K results in de...

The 3d core levels photoemission spectra of Rh(100) show linear magnetic dichroism in angular distribution (LMDAD) upon reversing the magnetic field in chiral experiments only when a small residual magnetic field is left applied to the sample. The intensity of the LMDAD effect does not depend on the magnitude of the applied residual field, but it s...

By means of high-energy resolution photoemission we show that the Rh(100) 3d5/2 surface core-level shift decreases when the surface temperature increases. The effect is interpreted as due to the expansion of the first interlayer distance, because of the different anharmonicity of the bulk and surface interatomic potentials, in agreement with theore...

Three components have been found in the Ru(1010) 3d5/2 core-level spectra. Based on a photoelectron diffraction experiment they have been assigned to emission from the bulk and the first two surface layers. The first layer line is shifted by -480 meV from the bulk peak position and the second layer line by -240 meV. The relative magnitude of the ob...

The structure of some novel oligomeric thiophene-containing π-conjugated Pd(II) complexes, recently prepared in our laboratory, Cl–Pd(PBu3)2-C≡C–C4H2S-C≡C–C4H2S–C≡C–C4H2S–C≡C-Pd(PBu3)2Cl or Pd–TRI and Cl[–Pd(PBu3)2–C≡C–C4H2S–C≡C–]3–Pd(PBu3)2Cl or Pd–DET, were studied by means of x-ray photoelectron spectroscopy. The interface formation between chro...

X-ray photoelectron spectroscopy was used in order to investigate the interface formation between chromium and thin films of a newly synthesised π-conjugated polymer P(PA-pNO2PA); the investigated material is a block copolymer consisting of phenylacetylene (PA) and para-nitro phenylacetylene (pNO2PA) units {[–(CHC–R)n–(CHC–R′)m–]N; RC6H5, R′C6H...

Core level and valence band photoemission, as well as X-ray absorption experiments, as a function of temperature have been performed on the C60 monolayer deposited on Ag(100) and polycrystalline Ag surfaces. Although the interaction of C60 with polycrystalline Ag can be classified as prevalently ionic of intermediate strength, in agreement with the...

The nature of bonding in amorphous carbon nitride was studied by synchrotron-radiation photoemission spectroscopy and near-edge x-ray-absorption fine structure. The experimental data are compared with theoretical calculations of chemical shifts, and the relative importance of initial and final state effects is discussed. Bond lengths are determined...

We present a pulse counting multichannel data acquisition system, characterized by the high number of high speed acquisition channels, and by the modular, embedded system architecture. The former leads to very fast acquisitions and allows to obtain sequences of snapshots, for the study of time dependent phenomena. The latter, thanks to the integrat...

High-resolution synchrotron radiation photoemission and absorption spectroscopies from the C1s core level were used to investigate a K3C60 (111) single-phase ordered film as a function of temperature. It is shown that the gradual slowing down of the molecular motions modifies the line shape of the C1s core level. Below 200 K the core-level data cle...

We propose a procedure based on the photoelectron diffraction technique to evaluate in-plane atomic distances for adsorbate systems and overlayers. A comparison between the experimentally determined angular position of the first order interference maxima in photoelectron diffraction azimuthal scans at the grazing angle and the same quantity calcula...

On the basis of a low energy electron diffraction I-V structural investigation, the surface geometry of the Rh100+2×2-2O phase has been determined. The oxygen is found to adsorb in an unusual threefold site of the rhombi created by the reconstruction of the first rhodium layer, producing a pg symmetry, in agreement with theoretical predictions but...

Clear evidence of magnetic ordering at the Rh(100) surface has been obtained by measuring the linear magnetic dichroism in the angular distribution of the Rh- 3d photoelectrons. The experiment is performed by reversing the orientation of the magnetic moments using an external magnetic field and observing the difference in the core level line shape....

In the latest generation of SR sources, local bump orbit feedback systems are under development for improving the stability of the delivered radiation. Photon Beam Position Monitors (PBPM) are being built as detectors of beam movements and as references for feedback systems. A new generation of PBPMs for undulator beamlines is being designed at ELE...

High-resolution synchrotron-radiation photoemission spectroscopy has been used to investigate the Si 2p core-level peak of the c(2×2) Si-Cu(110) surface alloy. In the photoemission spectrum several components can be clearly distinguished where only one would be expected. In order to know the atomic origin of these shifted components, we have correl...

Surface plasmon dispersion on Pd(110) was investigated along the high-symmetry directions (110) and (001) with angle-resolved electron-energy-loss spectroscopy. A large negative initial dispersion with transferred momentum is found in spite of the strong shift of plasmon and surface plasmon frequencies induced by the presence of the d bands. Their...

We present a software package developed on the LabVIEW platform which controls a synchrotron radiation experimental station for surface science experiments and allows users efficient use of the equipment. In contrast to other programming environments, LabVIEW offers programmers an effective way of integrating the functions of several real instrumen...

The band structure of lead sulphide has been investigated using angle-resolved photoemission, with synchrotron radiation in the photon energy range 25-95 eV as the excitation source. Many spectral features originate from direct transitions, while others are due to 'density of state' features, i.e. they arise from electrons scattered into the observ...

The adsorption and dissociation of NO on the Rh(110) surface were studied by synchrotron radiation X-ray photoemission spectroscopy at temperatures in the range 210–370 K. The O 1s or N 1s spectra were collected every 14 s while the surface was continuously exposed to a steady NO gas pressure. The difference in the binding energies for the atomic o...

New features of the interface between chromium and Pd-DEBP, [-Pd(PBu3)(2)-C=C-C6H4-C6H4-C=C-](n), a pi-conjugated organometallic polymer, were investigated by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Analysis of the Cls peak structure at increasing Cr coverage reveals that chromium reacts preferentially with the con...

Deposition of half atomic layer of Si on the Cu(110) surface leads to the formation of a stable c(2 × 2) superstructure. Our structural study by quantitative analysis of low-energy electron diffraction intensities finds a two-dimensional alloyed top layer in which Si atoms occupy substitutional Cu sites and are displaced inwards by 0.24 Å with resp...

The adsorption and temperature-dependent decomposition of SO2 on Ni(110) has been studied by core-level photoemission and X-ray absorption fine structure measurements. The analysis shows that on adsorption at 160 K SO2 partly decomposes, leaving SO3 and atomic S on the surface. Two different, nearly flat-lying SO2 species are observed which corresp...

Gas phase near-edge X-ray absorption fine structure spectra of phenylacetylene (PA, C6H5–CCH) have been recorded at the carbon K-edge. The experimental data have been interpreted with the help of ab initio calculations: both the ionisation potentials for the C1s electrons and the theoretical C K-edge absorption spectra have been calculated for all...

In this report, it is shown that the availability of synchrotron light from third generation facilities allows the acquisition time of XPS spectra to be cut by more than 2 orders of magnitude while enhancing the energy resolution. In turn, this makes it possible to extract much more detailed information about the composition of the surface layer fr...

High Energy Resolution X-ray Photoelectron Spectrocopy performed at a third generation synchrotron radiation source has been used to investigate the temperature dependence of the O1s and O2s core level photoemission signals from the O-(2x2)p2mg structure on Rh(110). This structure consists of chemisorbed oxygen atoms sitting in three-fold sites in...

High-resolution x-ray photoelectron spectroscopy has been used to investigate the temperature behavior of the O 1s and O 2s core-level photoemission signals from the O-(2×2)p2mg structure on Rh(110). With increasing temperature we observe a continuous shift of the photoemission peaks to lower binding energy. The width of the peaks increases with in...

Deposition of 0.5 Si monolayer (ML) on a Cu(110) surface at room temperature (RT) leads to the formation of a c(2×2) LEED pattern. In order to find out the surface atomic structure of this ordered phase, X-ray photoelectron diffraction (XPD) azimuthal scans at different photon energies and full hemispherical XPD patterns of the Si 2p core level hav...