X-Ray Spectroscopy — The Driving Force to Understand and Develop Catalysis

Catalysis is involved in about 90% of manmade chemicals. The development of novel or improved catalysts requires fundamental understanding of the commanding steps of a catalytic reaction. In simple terms, a catalytic transformation depends on the coupling between catalyst electronic structure and reagents’ molecular orbitals. Herein, we report a spectroscopic technique capable of determining the electronic structure of metal containing catalysts under working conditions. The technique is called photon-in photon-out X-ray spectroscopy and can be employed to characterize materials, unveil substrate adsorption parameters, and follow changes in electronic structure during catalytic reactions

Model organizacyjny związku komunalnego. W kierunku uelastycznienia ustawowej regulacji

The whole article is built around the thesis stating that the legal regulation of the organizational model of the municipal union is inflexible, which hinders the practical use of the institution. Local government laws using cogent norms do not give space to cooperating municipalities and/or counties to implement "tailor-made" organizational solutions, i.e. taking into account the conditions of the area (geographical, political, economic, social, etc.). These laws should therefore be amended. In addition to the normative analysis and de lege lata conclusions, several demands to the legislator were also presented, each exemplified by a proposed statutory provision.Artykuł zbudowano wokół tezy stanowiącej, że ustawowa regulacja modelu organizacyjnego związku komunalnego jest sztywna, co utrudnia praktyczne wykorzystanie instytucji. Ustrojowe ustawy samorządowe posługujące się normami o charakterze kogentywnym nie pozostawiają miejsca współdziałającym gminom i/lub powiatom na wdrażanie rozwiązań organizacyjnych „szytych na miarę”, czyli uwzględniających uwarunkowania danego obszaru (geograficzne, polityczne, gospodarcze, społeczne itd ). Należy zatem te ustawy w określony sposób zmienić Obok analizy normatywnej i wniosków de lege lata zaprezentowano także kilka postulatów do ustawodawcy, a każdy egzemplifikowano propozycją przepisu ustawowego

Performance of a laboratory von Hámos type x-ray spectrometer in x-ray absorption spectroscopy study on 3d group metals

With the recent progress regarding the development of x-ray instrumentation, compact x-ray spectrometers are becoming more and more popular as they allow x-ray absorption spectroscopy (XAS) and x-ray emission spectroscopy (XES) studies at the research institutes laboratories. Such setups provide a cost-effective tool for routine sample characterization with unlimited access and are of great utility in feasibility studies preceding the experiments at synchrotrons and x-ray free-electron lasers (XFELs). Herein, we present the operation and capabilities of the von Hamos type x-ray spectrometer in x-ray absorption spectra measurement for various 3d metal elements. Results allowed us to establish the photon counting performance of the setup, demonstrating a possible range of applications of the in-house x-ray spectroscopy apparatus

Heterogeneous Catalysis Experiments at XFELs. Are we Close to Producing a Catalysis Movie?

The advent of X-ray free electron lasers enabled scientist to achieve the goal of producing a movie of a catalytic transformation. This perspective highlights the technical developments both on facilities and X-ray spectroscopy that brought us a bit closer to attain the main goal. However there are a couple of issues that need to be solve, namely sample stability and selective triggering. Graphical Abstract

Novel reference-free methods for the determination of the instrumental response of Laue-type bent crystal spectrometers

We report on novel reference-free methods to determine the instrumental resolution of transmission-type bent crystal spectrometers. The novel methods are based on the measurements of a selected X-ray line in several orders of diffraction. It is shown that the angular broadening of the spectrometer and the natural linewidth of the selected transition can be obtained directly from the novel methods. No reference X-ray line or γ-ray line is needed. The precision of the results is about 10 times better than the one obtained with the standard method consisting of measuring a reference X-ray line and keeping fixed in the fit the natural width of this line at the value taken from available databases. The novel methods are illustrated for a DuMond-type bent crystal spectrometer with the Kα1 X-ray line of Gd measured in the first five orders of diffraction

Double K-shell photoionization and hypersatellite x-ray transitions of 12⩽Z⩽23 atoms

Single-photon double K-shell ionization of low-Z neutral atoms in the range 12⩽Z⩽23 is investigated. The experimental method was based on measurements of the high- resolution Kαh hypersatellite x-ray spectra following the radiative decay of the K-shell double-vacancy states excited by monochromatic synchrotron radiation. The photon energy dependence of the double K-shell ionization was measured over a wide range of photon energies from threshold up to and beyond the maximum of the double-to- single photoionization cross section ratios. From the high-resolution x-ray emission spectra the energies and linewidths of the hypersatellite transitions, as well as the Kαh1:Kαh2 intensity ratios, were determined. The relative importance of the initial-state and final-state electron-electron interactions to the K-shell double photoionization is addressed. Physical mechanisms and scaling laws of the K-shell double photoionization are examined. A semiempirical universal scaling of the double- photoionization cross sections with the effective nuclear charge for neutral atoms in the range 2⩽Z⩽47 is established

Laboratory von H\'amos X-ray Spectroscopy for Routine Sample Characterization

High energy resolution, hard X-ray spectroscopies are powerful element selective probes of the electronic and local structure of matter, with diverse applications in chemistry, physics, biology and materials science. The routine application of these techniques is hindered by the complicated and slow access to synchrotron radiation facilities. Here we propose a new, economic, easily operated laboratory high resolution von H\'amos type X-ray spectrometer, which offers rapid transmission experiments for X-ray absorption, and is also capable of recording X-ray emission spectra. The use of a cylindrical analyzer crystal and a position sensitive detector enabled us to build a maintenance free, flexible setup with low operational costs, while delivering synchrotron grade signal to noise measurements in reasonable acquisition times. We demonstrate the proof of principle and give examples for both measurement types. Finally, tracking of a several day long chemical transformation, a case better suited for laboratory than synchrotron investigation, is also presented

Współpraca THINK TANKÓW z organami administracji publicznej przy stanowieniu prawa

The paper “Cooperation between THINK TANKS and public administration in legislation process” presents the problem of think tanks participation in the process of administrative legislation. Nowadays their contribution to the execution of public functions of legislation is undoubtedly very beneficial. It is also preferred to use the results of parallel activities of administrative authorities and think tanks. As the analysis of existing legislation shows, the think tanks that are involved in the legislative process may use a wide variety of legal institutions. In addition, they possess a valuable base of experts and financial resources. To summarize, this paper shows that cooperation with think tanks allows the administration to achieve higher quality services at lower financial cost

X‐Ray Spectroscopy on Biological Systems

In the field of biological studies, next to the standard methods, new tools are offered by contemporary physics. X‐ray spectroscopic techniques enable probing electronic structure of occupied and unoccupied states of studied atom and distinguish the oxidation state, local geometry, and ligand type of elements that occur in biological material. Direct analysis using X‐ray spectroscopy avoids many chemical preparation steps that might modify biological samples. The information obtained gives us insight into important biochemical processes all under physiological conditions. In this chapter we focus our attention to the application of X‐ray spectroscopy to the study of biological samples, with special emphasis on mechanisms revealing interaction between DNA and different cytotoxic agents and in the determination of changes in oxidation state of different elements in pathologically altered human cells and tissue