A5057247629- Molecular Junctions and Nanostructures
- Advanced Chemical Physics Studies
- Surface Chemistry and Catalysis
- Porphyrin and Phthalocyanine Chemistry
- Electron and X-Ray Spectroscopy Techniques
- Surface and Thin Film Phenomena
- Catalytic Processes in Materials Science
- Photochemistry and Electron Transfer Studies
- Magnetism in coordination complexes
- X-ray Spectroscopy and Fluorescence Analysis
- Organic Electronics and Photovoltaics
- Electrocatalysts for Energy Conversion
- Spectroscopy and Quantum Chemical Studies
- Quantum and electron transport phenomena
- nanoparticles nucleation surface interactions
- Conducting polymers and applications
- Magnetic properties of thin films
- Semiconductor materials and devices
- Electronic and Structural Properties of Oxides
- 2D Materials and Applications
- Chemical and Physical Properties of Materials
- Fullerene Chemistry and Applications
- Advanced Photocatalysis Techniques
- Graphene research and applications
- CO2 Reduction Techniques and Catalysts
Uppsala University
2012-2022
Karlstad University
2015
Kista Photonics Research Center
2009
Helmholtz-Zentrum Berlin für Materialien und Energie
2009
Linköping University
2008
KTH Royal Institute of Technology
2003-2006
AlbaNova
2002-2006
Lawrence Berkeley National Laboratory
2005
Stockholm University
2002-2004
Elettra-Sincrotrone Trieste S.C.p.A.
1994-1998
We address the adsorption of water on Pt(111) using x-ray absorption, emission, and photoelectron spectroscopy along with calculations in framework density functional theory. Using direct relationship between electronic structure adsorbate geometry, we show that first layer all molecules bind directly to surface each other through in-layer H bonds without dissociation, creating a nearly flat overlayer. The are adsorbed alternating metal-oxygen (M-O) metal-hydrogen (M-HO) bonds.
For the electrochemical hydrogen evolution reaction (HER), electrical properties of catalysts can play an important role in influencing overall catalytic activity. This is particularly for semiconducting HER such as MoS2 , which has been extensively studied over last decade. Herein, on-chip microreactors on two model catalysts, and semimetallic WTe2 are employed to extract effects individual factors study their relations with It shown that electron injection at catalyst/current collector...
A joint experimental and theoretical work to explain the electronic geometrical structure of an in situ prepared film iron phthalocyanine (FePc) on silicon (100) is presented. FePc molecular films have been characterized by core valence photoemission spectroscopy (PES) x-ray absorption (XAS), results interpreted simulated density functional theory (DFT) calculations. C1s N1s PE spectra analyzed taking into account all chemically nonequivalent C N atoms molecule. In Fe2p3∕2 it has possible...
Abstract Using the MoS 2 ‐WTe heterostructure as a model system combined with electrochemical microreactors and density function theory calculations, it is shown that heterostructured contacts enhance hydrogen evolution reaction (HER) activity of monolayer . Two possible mechanisms are suggested to explain this enhancement: efficient charge injection through large‐area heterojunctions between WTe effective screening mirror charges due semimetallic nature The dielectric effect proven minor,...
There exists an extensive literature on the electronic structure of transition-metal phthalocyanines (TMPcs), either as single molecules or adsorbed surfaces, where explicit intra-atomic Coulomb interactions strongly correlated orbitals are included in form a Hubbard U term. The choice is, to large extent, based solely previous values reported for similar systems. Here, we provide systematic analysis influence electron correlation and magnetism several TMPcs (MnPc, FePc, CoPc, NiPc, CuPc)....
The shake-up transition energies of the carbon $1s$ photoelectron spectrum metal-free phthalocyanine $({\mathrm{H}}_{2}\mathrm{Pc})$ have been calculated by means time-dependent density functional theory, for which an equivalent core approximation is adopted. Model calculations $\mathrm{C}\phantom{\rule{0.2em}{0ex}}1s$ states benzene are in excellent agreement with latest experimental results. complex structures associated aromatic and pyrrole carbons computed, as well their ionization...
We analyse the valence electronic structure of cobalt phthalocyanine (CoPc) by means optimally tuning a range-separated hybrid functional. The is performed modifying both amount short-range exact exchange (α) included in functional and range-separation parameter (γ), with two strategies employed for finding optimal γ each α. influence these parameters on structural, electronic, magnetic properties CoPc thoroughly investigated. found to be very sensitive range which included. obtained using...
The Super-ESCA beamline has been designed for high resolution core level spectroscopy of adsorbates on single crystal surfaces using soft x-ray synchrotron radiation. It receives the light from an 81 period undulator with 5.6 cm and 4.5 m length in storage ring ELETTRA. tunability this insertion device, at a electron energy 2.0 GeV connected modified SX700 monochromator allows performance experiments photon range 100–2000 eV. This is now operational first absorption spectra are presented...
The electronic structure of a vapor-sublimated thin film metal-free phthalocyanine (H2Pc) is studied experimentally and theoretically. An atom-specific picture the occupied unoccupied states obtained using x-ray-absorption spectroscopy (XAS), core- valence-level x-ray photoelectron (XPS), density-functional theory (DFT) calculations. DFT calculations allow for an identification contributions from individual nitrogen atoms to experimental N1s XAS valence XPS spectra. This comprehensive study...
The electronic structure of iron phthalocyanine (FePc) in the valence region was examined within a joint theoretical-experimental collaboration. Particular emphasis placed on determination energy position Fe 3d levels proximity highest occupied molecular orbital (HOMO). Photoelectron spectroscopy (PES) measurements were performed FePc gas phase at several photon energies interval between 21 and 150 eV. Significant variations relative intensities observed, indicating different elemental...
One of the key factors behind rapid evolution molecular spintronics is efficient realization spin manipulation organic molecules with a magnetic center. The state such may depend crucially on interaction substrate which they are adsorbed. In this paper we demonstrate, using ab initio density functional calculations, that stabilization high an iron porphyrin (FeP) molecule can be achieved via chemisorption substrates different species and orientations, viz., Co(001), Ni(001), Ni(110),...
To shed light on the metal 3d electronic structure of manganese phthalocyanine, so far controversial, we performed photoelectron measurements both in gas phase and as thin film. With purpose explaining experimental results,three different configurations close energy to one another were studied by means density functional theory. The comparison between calculated valence band states measured spectra revealed that molecules exhibit a mixed configuration, while film, phthalocyanine finds itself...
Using x-ray emission and photoemission spectroscopies to measure the occupied valence levels in a thin crystalline ice film, we resolve ionization-induced dissociation of water on femtosecond time scale. Isotope substitution confirms proton transfer during core-hole lifetime spite nonresonant excitation. Through ab initio molecular dynamics core-ionized state, spectrum evolution are followed at intervals. The theoretical simulations confirm experimental analysis allow for detailed study...
The adsorption and temperature-dependent decomposition of ${\mathrm{SO}}_{2}$ on Cu(100) Cu(111) have been studied by fast high-resolution core-level photoemission. analysis the S 2p O 1s data shows that molecular dominates at 170 K. On heating ${\mathrm{SO}}_{2}$-covered surfaces to about room temperature, decomposes into SO+O+S. further SO+O recombine form ${\mathrm{SO}}_{2}$, which is only species detected in corresponding temperature-programmed desorption (TPD) experiments. From...
Low temperature scanning tunneling microscopy (STM) studies of metal-free phthalocyanine (H2Pc) adsorbed on highly oriented pyrolytic graphite (HOPG) have shown ordered arrangement molecules for low coverages up to 1 ML. Evaporation H2Pc onto HOPG and annealing the sample 670 K result in a densely packed structure molecules. Arrangements submonolayer, monolayer, monolayer with additional been investigated. The high resolution our investigations has permitted us image single molecule...
The coupling of submonolayer coverages Fe-phthalocyanine molecules on bare and oxygen-covered ferromagnetic Co(001) films was studied by x-ray-absorption spectroscopy, especially the x-ray magnetic circular dichroism, in combination with density functional theory. We observe that moments paramagnetic are aligned even at room temperature, resulting from a to substrate. While magnetization Fe ions directly adsorbed Co surface is parallel film, introduction an oxygen interlayer leads...
In this paper, we report a systematic study on the effect of different van der Waals dispersion correction methods in conjunction with Density Functional Theory adsorption characteristics monolayer metal-free phthalocyanine Au(111). The chosen corrections were DFT-D2, Tkatchenko-Scheffler method and without self-consistent screening, four sparse-matter density functionals. A comparison among was performed results are related to available experimental scanning tunnel microscopy x-ray...
In this article, we analyze the electronic structure modifications of triphenylamine (TPA), a well-known electron donor molecule widely used in photovoltaics and optoelectronics, upon deposition on Au(111) at monolayer coverage. A detailed study was carried out by synchrotron radiation-based photoelectron spectroscopy, near-edge X-ray absorption fine (NEXAFS) scanning tunneling microscopy (STM), ab initio calculations. We detect new feature pre-edge energy region N K-edge NEXAFS spectrum...
The dissociation of CO on size-distributed Rh particles supported a thin alumina film has been studied with high resolution X-ray Photoelectron Spectroscopy (XPS) and Absorption (XAS). Adsorbed dissociates upon heating to temperatures above 300 K. activity is dependent the island size, exhibiting maximum for islands around 1000 atoms. We have identified size-dependent changes in C 1s photoelectron spectra these CO–Rh systems occurring at lower than onset both desorption processes. These are...
Resonantly excited soft x-ray emission spectra of liquid water have been measured at two different angles relative to the polarization direction exciting radiation. The results demonstrate that is much more isotropic than expected for free molecule but trends in remaining anisotropy qualitatively agree. It found sharp oxygen peaks high energy correspond states symmetry.
Triphenylamine (TPA) and its thiophene-analog, N,N-diphenyl-2-thiophenamine (DPTA), are both well-known as electron-donating molecules implemented in optoelectronic devices such organic solar cells LEDs. Comprehensive valence core level photoelectron spectroscopy, well near edge X-ray absorption spectroscopy (NEXAFS), measurements have been performed on gas phase TPA DPTA. The experimental results compared to density functional theory calculations, providing a detailed description of the...