Schedule

Wednesday, 6/26/24, from 11:00am to12:00pm
Accelerate your concept of science
Dr. Christine Darve
European Spallation Source, Lund, Sweden

Abstract: “Accelerate Your Concept of Science” is a short course introducing the role of particle accelerators in modern science and their application in various careers. Participants will learn about particle accelerators and their impact on research and society. The course provides immersive modules and discussions on integrating accelerator science into STEM education, using examples from major facilities like CERN and the ESS.

Learning Objectives:

• Utilize large facilities to contextualize STEM teaching.
• Engage students with modern science through free digital tools.
• Understand particle accelerators and their societal contributions.

Bio: Dr. Christine Darve is an Engineering Scientist at the European Spallation Source (ESS) in Lund Sweden. She earned her Ph.D. in Superfluid Helium from Northwestern University, Illinois, after completing a Diplôme d’Ingénieur in Thermo-Mechanics of Systems and Materials at UTBM, France, in 1996. Dr Darve’s career at CERN in Geneva Switzerland, included significant contributions from the design to the operation of cryogenic systems. She then worked at Fermilab near Chicago for 12 years, contributing to the US-LHC collaborations through the design and testing of superconducting magnet cryostats. Since 2020, she has been with the In-Kind Management Division at ESS, following an 8-year tenure in the Accelerator Division where she led the design and integration of superconducting Radio-Frequency cavity Work Packages and the linear accelerator. Dr. Darve is the Chair of the International Union of Pure and Applied Physics Working Group 14 (IUPAP-WG14) and a former Chair of the Forum on International Physics (FIP) at the American Physical Society (APS). She co-founded the African School of Fundamental Physics and Applications (ASP) in 2010 and initiated Massive Open Online Courses incl. the Nordic Particle Accelerator Program (NPAP). A fellow of the APS since 2016, she also received the CERN Alumni Directorate Award in 2024.

Tuesday 7/2/27, from 10:00-11:00am
Controlling light with nanostructures
Dr. Andriy Shevchenko
Aalto University, Finland

Abstract: The lecture briefly covers the basics of interaction of light with nanoparticles (including Rayleigh and Mie scattering, plasmon resonances, near-field enhancement of light, and some standard applications of nanoparticles in optics), discusses higher-order electromagnetic multipoles (including their use to achieve optical magnetism, negative refraction, enhanced spatial dispersion, and exceptionally high intensity enhancement of light), and introduces the concept of dark states of light (employing electromagnetic anapoles and bound states in the continuum as examples). The lecture frequently uses the results obtained by the Optics and Photonics group led by the lecturer.

Bio: Andriy Shevchenko holds D.Sc. (Tech.) in optics (Helsinki University of Technology, Finland, 2004). In 2007, he was appointed as a docent in optical physics. Starting from 2020, he holds the position of a Senior University Lecturer at Aalto University, Finland. He leads the research of the Optics and Photonics group at Aalto University. His research and teaching interests include electromagnetism, nano-optics, optical imaging, laser physics, statistical optics, and optical metamaterials. He authored 83 refereed articles published in respectful international scientific journals and more than 100 conference contributions. Since 2019, he serves as a Topical Editor for Optics Letters (Light-matter Interaction at Nanoscale and Optical Metamaterials).

7/ 5/2024, from 12:00pm
Final Examination of Dave Austin for the degree of Doctor of Philosophy in Physics
Dissertation title: FIRST PRINCIPLES STUDIES OF NANOSCALE PHENOMENA AT SURFACES: FROM CHARACTERISTICS OF SINGLE ATOM CATALYSTS TO MOLECULAR STRUCTURE FORMATION
Zoom: zoom link

Abstract: The dissertation focuses on gaining a theoretical understanding of selected phenomena at surfaces that benefit from the novel electronic structure induced at surfaces through the adsorption of atoms and molecules. Of note are the physical and chemical properties of singly dispersed metal atom sites on oxide surfaces that have the potential to be cost-effective catalysts for reactions of technological and fundamental importance. Also of interest are hybrid organic-inorganic interface-driven novel molecular structure formations that display evidence of electron confinement. It utilizes density functional theory (DFT) based calculations to predict and simulate atomic-scale behaviors. The results aim to contribute to understanding reaction mechanisms and factors that enhance catalytic activity and the engineering of functional nanostructures.

One study examines the pathways for water-gas shift reaction for singly dispersed platinum atoms coordinated with a 10-phenanthroline-5,6-dione ligand adsorbed on a titanium oxide surface and compared it to that in the absence of the ligand. Vacancies in the titanium oxide surface are found to be important, and their role in controlling the reaction pathway is delineated.  It is shown that the ligand helped stabilize the platinum atom, thus reducing carbon monoxide poisoning and promoting a more efficient reaction that would otherwise have been the case. In another set of studies, vibrational frequencies of carbon monoxide are used to identify the local geometric and electronic structure of singly dispersed platinum atoms on ceria calcinated at two different temperatures, which display marked different propensities for carbon monoxide and ammonia oxidation.

Another study focuses on the electronic structure of bistable molecules with potential applications as a molecular switch. This is motivated by STM measurements, which show two stable configurations of the organic molecule diazodiphenlethane on Cu(111). DFT calculations establish the existence of the two stable configurations, one electrically conductive and the other not. It is shown that these two configurations have very different electronic structures, one showing characteristics of strong hybridization with the surface and the other retaining features of the gas phase molecule.

Similarly, DFT calculations lead to the formation of striking patterns for the overlayer of the organic molecule 4,7-dibromobenzo[c]-1,2,5-thiadiazole on Au(111), whose calculated images provide a rationale for those observed by scanning tunneling microscopy. DFT calculations of the band structure and electronic-structure analysis help unravel a unique pattern known as a Kagome lattice. The molecule’s modulation of the Au surface is traced to be the reason for the electron confinement despite a weak interaction between the molecular layer and the Au surface. The above examples lead to the main thesis that the local atomic environment and the accompanying electronic structure are responsible for the ensuing novel properties of these intriguing systems.

Hydrogen Production from Renewable Energies: Fundamental Insights into the Long-Term Stability of Electrode Coatings in Water Electrolysis

Dr. Herbert Over

Physical Chemistry Department, Justus Liebig University Giessen, Germany

Abstract: I will begin with a general discussion of why we need to shift from burning fossil fuel to renewable energy sources, where electrical energy instead of heat is the primary energy carrier. In this transformation process of decarbonizing the economy and society, the hydrogen production from renewable energy sources plays a crucial role in establishing a future hydrogen economy. Hydrogen is used to store electrical energy for extended periods of time and can be converted back to electrical energy by using fuel cells, but more importantly, hydrogen serves as the chemical feedstock needed to convert highly oxidized carbon molecules (such as CO2 or lignin) into value-added hydrocarbons without emitting CO2. From renewable energy sources, hydrogen is produced by acidic water electrolysis, which can cope with the intermittency of solar and wind power. One of the major technical challenges in water electrolysis is the missing long-term stability of the electrode coating, especially that of the anode. I will discuss the operation of the acidic water electrolyzer and how to gain fundamental insights into the corrosion process of state-of-art anode coating materials based on iridium and ruthenium. Designing appropriate model systems and employing dedicated experimental techniques from surface science, we are able to follow the corrosion process and share our fundamental knowledge with theoreticians.

Resume Dr. Herbert Over:

– Studied and finished electro engineering at the Applied university (FH) Bingen: 1976-1980

– Studied and finished physics at the technical university (TU) Berlin from 1980-1989

– Studied and finished mathematics at the TU Berlin from 1981-1990

– Ph. D. thesis in chemistry, free university (FU) Berlin 1991 under the supervision of Prof. G. Ertl (Nobel Laureate in chemistry, 2007)

– Postdoc at University in Milwaukee, Wisconsin, USA (surface physics): 1992-1993

– Habilitation at the FU Berlin, physical chemistry, 1996

– Since Jan. 2002: Professor in physical chemistry at the Justus Liebig University in Giessen with research focus on surface chemistry, thermal catalysis and electrocatalysis (water electrolysis), tightly combining experiment with theory.

– About 220 peer-reviewed papers mostly in ACS journals, H index: 65

Model catalysis from ultra-high vacuum to operando conditions: Solving grand challenges on the nanoscale

Dr. Lars Mohrhusen

Carl von Ossietzky Universität Oldenburg, D-26129 Oldenburg, Germany

Contact: lars.mohrhusen@uol.de

Abstract: To overcome some of the current challenges, especially in the energy transition, heterogeneous catalysis is a key technology. More than 90 % of all products in the chemical industry rely on catalytic processes, and thus the annual global catalyst market easily crosses the 30 billion-dollar range, not necessary to mention the huge value creation based on such processes.

The utilization of greenhouse gasses such as CO2 as a carbon source to form valuable chemicals as a feedstock for e.g. fuels or polymers is one of the most prominent examples in the focus of current research. Ideally, one would use the power of sunlight to drive this reaction. However, for this we are still lacking the appropriate catalyst materials, that are cheap and available, stable and nontoxic, but very reactive and ideally selective. In my group, we target to derive such materials based on rational material design.

In the industry, heterogeneous catalysts are often developed in a trial-and-error approach, as the harsh conditions within the industrial reactor plants (some hundred °C, 10 -300 bars) usually prevent the use of sophisticated methods that would allow the required atomic level understanding. In addition, the optimal catalysts usually are very complex multielement mixtures that are dynamic under reaction conditions. In consequence, working catalysts often appear as a black box. Distinct mechanism of how specific catalysts work often remain unclear for decades, as well as the reasons of deactivation that limit a catalyst’s lifetime. To overcome these limitations, we perform experimental modeling by using well-defined (single crystal) samples under ultra-high vacuum (< 10-9 mbar) or so-called operando conditions (usually few mbars). Combining insights from spectroscopy, microscopy and reactivity studies can gain a comprehensive picture. In this talk, I will briefly introduce the concept of the so-called “surface science approach” or “experimental modeling” and show, how this will for example help us to save energy in the production of chemicals, to make the industry more sustainable by using alternative feedstocks for modern fuels and improve the lifetime of limitedly available noble-metal components.

CV Dr. Lars Mohrhusen:

Synthesis and Characterization of Nanostructured Materials for solar driven Photocatalysis

Dr. Rania Adam

Carl von Ossietzky Universität Oldenburg, Germany

Abstract: Nanostructured materials for solar driven photocatalysis such as photodegradation of organic pollutants and photoelectrochemical (PEC) water oxidation for hydrogen production are very attractive because of the positive impact on the environment. Metal oxides-based nanostructures are widely used in photocatalysis due to their unique properties. But single nanostructured material might suffer from low efficiency and instability in aqueous solutions under solar light. These facts make it important to have an efficient and reliable nanocomposite for the photocatalysis. The combination of different nanomaterials to form a composite configuration can produce a material with improved properties.

Two photocatalysis application are examined with nanocomposites material based on Zinc oxide, and Copper oxide semiconductors. These applications are: the photodegradation of organic dyes, and PEC water splitting.

The characterization and photocatalysis experiment results showed remarkable enhancement in the photocatalysis performance of the synthesized nanocomposites.