Experiment: introduction to XPS

• Anna Regoutz (University of Oxford)

Room: Physicum A106

Experiment: XPS instrumentation (1)

• Ad Ettema (Scienta Omicron)

Room: Physicum A106

Experiment: XPS instrumentation (2)

• Andreas Thissen (SPECS Surface Nano Analysis)

Room: Physicum A106

Theory: introduction to DFT with a focus on surface species (1)

• Lukas Hörmann (University of Vienna)

Room: Physicum A106

Theory: the Δ-Self-Consistent-Field method

• J. Matthias Kahk (Institute of Physics, University of Tartu)

Room: Physicum A106

Experiment: XPS and HAXPES

• Anna Regoutz (University of Oxford)

Room: Physicum A106

Theory: introduction to DFT with a focus on surface species (2)

• Lukas Hörmann (University of Vienna)

Room: Physicum A106

Theory: the Δ-Self-Consistent-Field method (continued)

• J. Matthias Kahk (Institute of Physics, University of Tartu)

Room: Physicum A106

Experiment: synchrotron radiation

• Marco Kirm (Institute of Physics, University of Tartu)

Room: Physicum A106

Experiment: Auger processes and photofragmentation

• Marta Berholts (University of Tartu)

Room: Physicum A106

Experiment: XPS combined with ion detection for deeper insight into photodynamics

• Edwin Kukk (University of Turku)

Room: Physicum A106

From core to valence states: a comprehensive experimental and theoretical photoelectron spectroscopy study of proteinogenic amino acids

• Shiyang (Ann) Lu

Room: Physicum A106 Amino acids (AAs) are fundamental building blocks of life. In the solid state, AAs are of considerable scientific and technological interest due to their widespread use in the food and pharmaceutical industries. Despite this, most spectroscopy studies focus on gas-phase species or surface adsorbates, while crystalline AAs remain underexplored, largely because of experimental challenges associated with radiation damage. A detailed understanding of chemical bonding in solid-state AAs, encompassing both intra- and inter-molecular interactions, is nevertheless of great interest. Photoelectron spectroscopy provides access to this information, however, spectra are often complex and difficult to interpret. This motivates a combined experimental-theoretical approach, in which density functional theory (DFT) is used to calculate simulated spectra based on known crystal structures. Composed primarily of light elements, readily available in high purity and crystallinity, and exhibiting systematic variation in key chemical motifs, proteinogenic AAs constitute an ideal model system for validating the robustness of such an integrated experiment-theory framework. Photoelectron spectroscopy measurements, including core, semi-core, and valence states, form the experimental basis with a particular focus on the mitigation of radiation damage. Calculated relative core binding energies show excellent agreement with experiment and enable reliable assignments. Projections of the density of states provide insight into the influence of local coordination and extended crystal structure, yielding a systematic understanding of the electronic structure and bonding in solid-state AAs. This work presents a computationally efficient strategy for unlocking the information encoded in experimental photoelectron spectra and lays the foundation for a broader application of theory-assisted photoelectron spectroscopy.

The ALD of HfO2 Using Ozone as a Co-Reactant

• Zephyr Rosenblod

Room: Physicum A106 We investigated the effect ozone has on the ALD of HfO2 on top of Si substrates, where typically water has been used as a co-reactant. Curiously, despite the potential of ozone, we discovered that molecular oxygen is also a strong co-reactant. By varying temperature and following ambient pressure reactions in real time using PES, we distinguish the subtle contributions of O2 and O3 in ALD chemistry at the surface. This is the first use ozone together with the ALD setup at the SPECIES beamline of MAX IV in Lund, Sweden and promises increased opportunities for future users of the facility.

Theoretical Simulations of Li-S Battery Materials and X-ray Spectroscopic Analysis

• Ayda Gholamhosseinian (Freiburg Center for Interactive Materials and Bioinspired Technologies (FIT), University of Freiburg, Georges-K¨ohler-Allee 105, 79110 Freiburg, Germany.)

Room: Physicum A106 % TITLE {\large{\bf Theoretical Simulations of Li-S Battery Materials and X-ray Spectroscopic Analysis} } % AUTHORS \vskip0.5\baselineskip{\bf \underline {Ayda Gholamhosseinian}$^{1}$, Michael Walter$^{1}$ } % AFFILIATION \vskip0.5\baselineskip{\em$^{1}$(Presenting author underlined) Freiburg Center for Interactive Materials and Bioinspired Technologies (FIT), University of Freiburg, Georges-Köhler-Allee 105, 79110 Freiburg, Germany.\\ \end{center} \noindent % ABSTRACT Lithium–sulfur (Li–S) batteries are promising candidates for energy storage systems due to having a high theoretical capacity (1675 mAh/g)\,\cite{marmorstein2000electrochemical, ji2010advances}, but also face some challenges, such as the polysulfide shuttle effect, which causes the battery capacity to decrease during charge and discharge cycling. There are different approaches to overcoming these challenges \,\cite{li2019comprehensive}, one way is to covalently bond sulfur chains to organic structures\,\cite{li2019comprehensive, simmonds2014inverse} such as Naphthalene Diimide (NDI), and N-methylpyrrolidone (NMP). This covalent C–S bonding not only anchors sulfur, reduces the shuttle effect, but also provides additional redox-active sites from the organic backbone. Furthermore, by controlling the sulfur chain length through inverse vulcanization, we can balance high capacity (longer chains) with improved cycling stability (shorter chains). In the present study, to have a comprehensive picture of the electronic states, we simulate X-ray absorption spectroscopy (XAS), X-ray emission spectroscopy (XES), and resonant inelastic X-ray scattering (RIXS) with density functional theory (DFT) performed using the GPAW code\,\cite{mortensen2024gpaw, johnsen2025explicit}. XAS probes unoccupied electronic states, while $\alpha$-XES corresponds to a core-to-core transition (S $2p \rightarrow 1s$). In contrast, $\beta$-XES involves valence-to-core transitions and therefore provides information on occupied valence states and is more sensitive to the chemical environment \,\cite{ribson2025}. XES spectra are usually measured in the non-resonant region at incident energies around 2800 eV\,\cite{qureshi2021,ribson2025}, much higher than the sulfur K-edge absorption energy of about 2470 eV. In RIXS, the energy of incident and emitted photons is correlated, allowing us to study both occupied and unoccupied states, as well as provide information on sulfur species within complex chemical environments. We compare our simulations to X-ray spectroscopy measurements from our experimental collaborators. Our calculations indicate that variations in the dihedral angle of the sulfur chains and changes in the S–S bond length lead to shifts in the core-excitation energies in the XAS spectra. This combined experimental–theoretical approach provides insight into structure–property relationships and supports the rational design of stable, high-capacity polymer-based cathodes for next-generation Li–S batteries.

Microstructural evolution of CuO, WO3 and CuO-WO3 nanoparticles-based films studied by XPS

• Michal Procházka (New Technologies Research Centre, University of West Bohemia in Pilsen, Univerzitní 8, 301 00 Pilsen, Czech Republic)

Room: Physicum A106 Interest in clean and sustainable technologies is rapidly growing and hydrogen is widely used in this field. With this development, more emphasis is placed on hydrogen gas sensors as hydrogen poses significant risks due to its explosive nature and flammability [1]. Structural parameters and surface properties plays a significant role in interaction of gas with sensor material [2]. Therefore, the nanoparticles of various materials are more and more explored. To understand the surface evolution after annealing in the air we measured XRD, SEM and XPS of CuO, WO3 and CuWO nanoparticles-based films prepared by magnetron-based gas aggregation technique. [1] P. S. Chauhan, S. Bhattacharya, Hydrogen gas sensing methods, materials, and approach to achieve parts per billion level detection: A review, Int. J. Hydrogen Energy. 44 (2019) 26076–26099. https://doi.org/10.1016/j.ijhydene.2019.08.052. [2] H. Zhao, Y. Wang, Y. Zhou, Accelerating the Gas–Solid Interactions for Conductometric Gas Sensors: Impacting Factors and Improvement Strategies, Materials (Basel). 16 (2023). https://doi.org/10.3390/ma16083249.

Theory: The GW method

• Johannes Lischner (Imperial College London)

Room: Physicum A106

Theory: The GW method (continued)

• Johannes Lischner (Imperial College London)

Room: Physicum A106

Experiment: Core level spectroscopy of liquids

• Olle Björneholm (Uppsala University)

Room: Physicum A106

Theory: core level spectroscopy of surface species

• Reinhard Maurer (University of Vienna)

Room: Physicum A106

Theory: XPS of transition metal compounds (1)

• Atsushi Hariki (Osaka Metropolitan University)

Room: Physicum A106

Theory: XPS of transition metal compounds (2)

• Atsushi Hariki (Osaka Metropolitan University)

Room: Physicum A106

Theory: core level satellites in XPS (remote talk)

• John Rehr (University of Washington)

Room: Physicum A106