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Seemingly simple yet surprisingly difficult to probe, excess protons in water constitute complex quantum objects with strong interactions with the extended and dynamically changing hydrogen-bonding network of the liquid. Proton hydration plays pivotal roles in energy transport in hydrogen fuel cells and signal transduction in transmembrane proteins. While geometries and stoichiometry have been widely addressed in both experiment and theory, the electronic structure of these specific hydrated proton complexes has remained elusive. Here we show, layer by layer, how utilizing novel flatjet technology for accurate x-ray spectroscopic measurements and combining infrared spectral analysis and calculations, we find orbital-specific markers that distinguish two main electronic-structure effects: Local orbital interactions determine covalent bonding between the proton and neigbouring water molecules, while orbital-energy shifts measure the strength of the extended electric field of the proton. © 2022 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.

Climate change is generally expected to have a positive effect on weathering rates, due to the strong temperature dependence of the weathering process. Important feedback mechanisms such as changes in soil moisture, tree growth and organic matter decomposition can affect the response of weathering rates to climate change. In this study, the dynamic forest ecosystem model ForSAFE, with mechanistic descriptions of tree growth, organic matter decomposition, weathering, hydrology and ion exchange processes, is used to investigate the effects of future climate scenarios on base cation weathering rates. In total, 544 productive coniferous forest sites from the Swedish National Forest Inventory are modelled, and differences in weathering responses to changes in climate from two Global Climate Models are investigated. The study shows that weathering rates at the simulated sites are likely to increase, but not to the extent predicted by a direct response to elevated air temperatures. Besides the result that increases in soil temperatures are less evident than those in air temperature, the study shows that soil moisture availability has a strong potential to limit the expected response to increased temperature. While changes in annual precipitation may not indicate further risk for more severe water deficits, seasonal differences show a clear difference between winters and summers. Taking into account the seasonal variation, the study shows that reduced soil water availability in the summer seasons will strongly limit the expected gain in weathering associated with higher temperatures.

Ion accelerators have demonstrated tremendous versatility in their research applications throughout several decades. Starting predominantly as nuclear physics tools, they subsequently provided novel insights into fundamental atomic physics. Nowadays small and medium size accelerators are routinely employed in several branches of materials science. As research questions increasingly drive the need for analyses and material modification experiments performed in-situ and/or in-operando, facilities must adapt to service such a need. In this work, we highlight capabilities for in-situ and in-operando composition depth profiling and materials modification, developed with instrumentation at the Tandem Laboratory at Uppsala University. An overview of available ion sources and accelerators is given. We then exemplify the specific capabilities of the available end stations for materials synthesis, sample modification and device operation either during simultaneous ion beam based characterization or with such characterization performed in-situ before and after the application of various modification steps. Describing specific recent examples and potential future applications, we illustrate the impact of the present national research infrastructure.

This dissertation covers the development and calibration of the Jovian plasma Dynamics and Composition analyzer (JDC). JDC is together with five other sensors a part of the Particle Environment Package (PEP), one of the payloads of the European Space Agency's JUpiter ICy moons Explorer (JUICE) mission. The JUICE mission is designed to broaden our understanding of the Jovian system including Jupiter, the four Galilean moons (Io, Europa, Ganymede and Callisto) and Jupiter's vast magnetosphere. JUICE is planned to launch in 2023. The PEP payload will study the plasma environment around Jupiter and its moons in great detail. As one of the sensors of PEP, JDC will measure the energy distribution of positive and negative ions as well as electrons in an energy range from a few eV/q up to 35keV/q. The field of view covered by JDC spans over a full hemisphere. JDC also determines the mass of particles using the time-of-flight principle. Alternatively, there is the possibility to determine the distribution of particle arrival times to study their distribution in the time domain. In this thesis, ion-optical, mechanical, electrical, thermal, radiation shielding and instrument operation related design solutions are presented and discussed. Special attention was paid to the performance of the channel electron multipliers used as time-of-flight start detectors. To verify their performance throughout the whole mission, a full lifetime test for these detectors was successfully performed. As a result of this test a qualitative performance model for channel electron multipliers was developed. Another experiment included in this work is the determination of the residual gas pressure evolution inside of JDC. A sufficiently low residual gas pressure is required for safe operation of JDC's high voltage systems. Finally, the performance of the JDC linear electric field reflectron was verified using a dedicated prototype. The last part of this work describes the methods used for instrument, Den här avhandlingen behandlar utvecklingen och kalibreringen av instrumentetJovian plasma Dynamics and Composition analyzer (JDC). JDC utgör tillsammans med fem andra sensorer Particle Environment Package (PEP), som är ett av experimenten på European Space Agency:s rymdsond Jupiter Icy moons Explorer (JUICE). JUICE uppdrag är att bredda och fördjupa vår kunskap om Jupiter-systemet. Rymdsonden ska skjutas upp 2023 och studera Jupiter, Jupiters magnetosfär och de fyra Galileiska månarna (Io, Europa, Ganymedes och Callisto). Instrumentpaketet PEP är konstruerat för att undersöka plasmamiljön kring Jupiter och dess månar i detalj. Sensorn JDC har som sin specifika uppgift att observera energifördelningen hos positiva och negativa joner samt elektroner i ett energiområde från några få eV/q (elektronvolt per laddningsenhet) upp till 35 keV/q. JDC:s synfält är en hel hemisfär och instrumentet använder flygtidsprincipen för att bestämma massorna hos de partiklar som observeras. Det finns också en möjlighet att istället registrera partiklarnas ankomsttider för att titta på fördelningen i tidsdomänen. I avhandlingen presenteras jonoptiska, mekaniska, elektriska och termiska konstruktionslösningar för JDC. Aspekter relaterade till strålningsskärmning och drift av instrumentet diskuteras också. Vi tittar särskilt på prestandan hos de kanalelektronmultiplikatorer som används som startdetektorer i flygtidssystemet. För att undersöka hur de kommer att fungera under den långa expeditionen har ett livstidstest utförts. Utgående från resultaten har en kvalitativ prestandamodell tagits fram. Ett annat experiment som avhandlingen behandlar är undersökningen av hur residualgastrycket utvecklas inuti JDC. För att de högspänningssystem som finns inuti instrumentet ska fungera utan risk för överslag måste trycket vara tillräckligt lågt. Slutligen diskuteras användningen av en särskild prototyp för att verfiera funktionaliteten hos den så kallade ’reflektronen’, en av JDC:s centrala delar., Various Pagination.

In this work, we report on a new lead(II) coordination complex [Pb2L2(CH3CN)(ClO4)2]·2H2O (1·2H2O), which was readily synthesized from a mixture of Pb(ClO4)2·3H2O and 1-(pyridine-2-yl)benzylidene-4-phenylthiosemicarbazide (HL). The crystal structure analysis of 1·2H2O evidenced that the lead(II) cation is N,N',S-chelated by the tridentate pincer type L with formation of a [PbL]+ coordination species, which dimerizes through a couple of reciprocal bridging Pb–S bonds, yielding the [Pb2L2]2+ complex cation. The metal centers within this cation are linked by two Pb∙∙∙N tetrel bonds through the bridging acetonitrile molecule with the formation of a [Pb2L2(CH3CN)]2+ building unit. These units are glued by reciprocal Pb∙∙∙S tetrel bonds, yielding a 1D supramolecular polymeric chain. The lead(II) cations interact also with disordered oxygen atoms of both the minor and major occupancies of the perchlorate anions either through covalent Pb–O bonds or Pb∙∙∙O tetrel bonds, respectively. 1D polymeric chains resemble an expanded hexagonal projection and span along the a axis, yielding a grid-like crystal packing, where the cavities are filled by lattice water molecules. The interactions have been studied using DFT calculations and characterized by using the quantum theory of atoms-in-molecules (QTAIM) and the non-covalent interaction plot (NCIplot) computational tools. © 2022 The Author(s)

The hydrogen-bonding interaction is studied in imidazolium-based mesogenic ionic liquids in their isotropic, smectic, and solid phases and in a nanoconfined state by proton solid-state nuclear magnetic resonance (NMR). In the smectic phase, the more basic anions form stronger hydrogen bonds. A small decrease of H-bonding in the mesophase with respect to that in the isotropic phase is associated with the presence of a layered assembly with high orientational order and limited conformational freedom. Hydrogen bond strength is not sensitive to the cation structural modification as long as the aprotic nature of the material is preserved. The strong cation-anion hydrogen bonding observed in the smectic phases provides direct support for the presence of ionic sublayers which form in ionic liquid crystals regardless of the location and alignment of the charged group in the cation, particularly irrespective of whether the charged group occupies a terminal or central position in the cation structure. A comparison of the results obtained in isotropic, liquid-crystalline, and solid states shows that in the bulk materials the dynamic state of ions ranging from high reorientational and translational freedom to partial orientation and positional order to full immobilization, respectively, has no strong impact on the cation-anion hydrogen bond strength. On the other hand, nanoconfinement of ionic liquid crystals led to hydrogen bond disruption due to competing interactions of anions with a solid interface., QC 20230602

The synthesis and crystallographic site occupancy were investigated for MgAl2O4 with and without mechanical activation of the precursor powders. Heating to 1200 °C or higher resulted in the formation of a single spinel phase regardless of whether the powders were mechanically activated or not. Neutron diffraction analysis was used to determine cation site occupancy and revealed that mechanical activation resulted in a lower degree of cation site inversion compared to the nonactivated materials, which indicated that the powders were closer to thermodynamic equilibrium. This is the first study to characterize the effects of mechanical activation on crystallographic site occupancy in magnesium aluminate spinel using neutron diffraction. © 2022 by the authors.

To reduce undesired iron leaching in Fenton reaction and to realize reusability of catalyst, chitosan-coated activated carbon cloth support loaded with nano zero-valent iron (ACC–CH–nZVI) was applied as a heterogeneous Fenton catalyst to treat melanoidin wastewater. Chitosan coating on ACC by chemical crosslinking results in 6% chitosan on ACC subsequently loading 3.5% iron. At optimum conditions, ACC–CH–nZVI leads to 88.4% and 76.2% of color and chemical oxygen demand (COD) removal, respectively, upon treating synthetic melanoidin wastewater of 8000 mg/l COD. The corresponding weight ratio of consumed H2O2 to COD is 1.02, far below the stoichiometric ratio 2.125, indicating the economic value of this catalyst. Reusability of ACC–CH–nZVI is demonstrated for five cycles of treatment with minimal iron leaching (<2%). The high removal efficiency and very low levels of iron leaching suggests that ACC–CH–nZVI is a highly efficient and cost-effective catalyst for Fenton-like oxidation of non-biodegradable organic wastes in water., QC 20201202

In this work we report a new Hg(II) coordination compound [Hg(HL)(SCN)2], which was readily obtained from a mixture of Hg(SCN)2 and N'-(1-(pyridin-2-yl)ethylidene)nicotinohydrazide (HL). The metal cation is chelated by the organic ligand in a N,N',O tridentate manner through the 2-Py and amide nitrogen donors, and carbonyl oxygen atom. The coordination sphere is filled by the sulfur donors of two thiocyanate anions, thus yielding a pentacoordinated geometry, which is best described as being about 64% along the pathway of distortion from the ideal square pyramidal toward trigonal bipyramidal structure. In addition, the metal center forms two types of the Hg⋯N spodium bonds, which are formed with the 3-Py nitrogen atom of a symmetry related molecule and with the nitrogen atom of one thiocyanate ligand of another molecular unit. These Hg⋯N spodium bonds enlarge the coordination environment of the metal cation in between a capped trigonal prism close to pentagonal bipyramid. In addition a 1D zig-zag-like polymeric chain is formed, which is further reinforced by bilateral C–H⋯O hydrogen bonds. These chains are interlinked through N–H⋯N hydrogen bonds and additionally glued by π⋯π interactions between the 2-Py rings. Thus, considering all the Hg⋯N spodium and N–H⋯N hydrogen bonds, a supramolecular 2D layer is formed with a binodal 3,4-connected hcb topology. The 2D layers are interlinked through a myriad of π⋯π interactions. According to the Hirshfeld surface analysis, the crystal packing of [Hg(HL)(SCN)2] is mainly characterized by intermolecular H⋯H, H⋯C, H⋯N and H⋯S contacts comprised from 15.9 to 22.3%, followed by less significant H⋯O, C⋯C, C⋯N, N⋯S and Hg⋯N contacts comprised from 2.8 to 6.3%. The intermolecular H⋯C, H⋯N, H⋯O, H⋯S and C⋯C contacts are highly favoured in the molecular surface of [Hg(HL)(SCN)2], while the N⋯S contacts are less favoured, and remaining contacts are significantly impoverished. Finally, density functional theory (DFT) calculations at the

Electrolytic deposition (ELD) and electrophoretic deposition (EPD) are relevant methods for creating functional layers of solid oxide fuel cells (SOFCs). This review discusses challenges, new findings and prospects for the implementation of these methods, with the main emphasis placed on the use of the ELD method. Topical issues concerning the formation of highly active SOFC electrodes using ELD, namely, the electrochemical introduction of metal cations into a porous electrode backbone, the formation of composite electrodes, and the electrochemical synthesis of perovskite-like electrode materials are considered. The review presents examples of the ELD formation of the composite electrodes based on porous platinum and silver, which retain high catalytic activity when used in the low-temperature range (400–650 °C). The features of the ELD/EPD co-deposition in the creation of nanostructured electrode layers comprising metal cations, ceramic nanoparticles, and carbon nanotubes, and the use of EPD to create oriented structures are also discussed. A separate subsection is devoted to the electrodeposition of CeO2-based film structures for barrier, protective and catalytic layers using cathodic and anodic ELD, as well as to the main research directions associated with the deposition of the SOFC electrolyte layers using the EPD method. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

Lead halide perovskites have become a leading material in the field of emerging photovoltaics and optoelectronics. Significant progress has been achieved in improving the intrinsic properties and environmental stability of these materials. However, the stability of lead halide perovskites to ionising radiation has not been widely investigated. In this study, we investigated the radiolysis of lead halide perovskites with organic and inorganic cations under X-ray irradiation using synchrotron based hard X-ray photoelectron spectroscopy. We found that fully inorganic perovskites are significantly more stable than those containing organic cations. In general, the degradation occurs through two different, but not mutually exclusive, pathways/mechanisms. One pathway is induced by radiolysis of the lead halide cage into halide salts, halogen gas and metallic lead and appears to be catalysed by defects in the perovskite. The other pathway is induced by the radiolysis of the organic cation which leads to formation of organic degradation products and the collapse of the perovskite structure. In the case of Cs0.17FA0.83PbI3, these reactions result in products with a lead to halide ratio of 1 : 2 and no formation of metallic lead. The radiolysis of the organic cation was shown to be a first order reaction with regards to the FA+ concentration and proportional to the X-ray flux density with a radiolysis rate constant of 1.6 × 10-18 cm2 per photon at 3 keV or 3.3 cm2 mJ-1. These results provide valuable insight for the use of lead halide perovskite based devices in high radiation environments, such as in space environments and X-ray detectors, as well as for investigations of lead halide perovskites using X-ray based techniques., QC 20220318

Ameso-functionalization strategy has successfully been applied to the synthesis of novel 1,3,7-triazapyrene derivatives of calixarenes. The key synthetic step in these transformations providing the direct C-C bond formation is nucleophilic substitution of hydrogen (SNH) in 1,3,7-triazapyrene. General photophysical characteristics for these macrocyclic compounds, as well as features in emission properties upon addition of various metal cations have been elaborated. Studies using NMR spectroscopy have also shown a mutual effect of both calix[4]arene and 1,3,7-triazapyrene moieties on the coordination process. The complex stoichiometry and binding constants for Al3+and Fe3+guests have been explored with titration experiments. © The Royal Society of Chemistry 2021.

Biochars have been shown as promising materials for cadmium remediation. However, the different precursors and the pyrolysis process operating conditions can yield very different surface functional groups, and as a result, different cadmium sorption mechanisms can be observed in biochars. Herein we present the results of cadmium sorption on biochars produced from the pyrolysis of different agro-residues, namely, coffee husk, quinoa straw, and oil palm kernel shell. The adsorption isotherms were used to determine the influence of the biochar's physicochemical characteristics to their sorption behavior. The biochars prepared from quinoa residues showed much higher cadmium uptakes than the other biochars. The concentration of base cations was found to be a critical factor for cadmium sorption. Although the quinoa biochars presented large uptakes, it was found that base cations were supported on the biochars and could be removed by leaching. Results from this study suggest that concentration of base cations on biochars could be used as predictors of the biochar capabilities for the removal of cadmium in aqueous solution. Copyright © 2020 American Chemical Society.

Biochars have been shown as promising materials for cadmium remediation. However, the different precursors and the pyrolysis process operating conditions can yield very different surface functional groups, and as a result, different cadmium sorption mechanisms can be observed in biochars. Herein we present the results of cadmium sorption on biochars produced from the pyrolysis of different agro-residues, namely, coffee husk, quinoa straw, and oil palm kernel shell. The adsorption isotherms were used to determine the influence of the biochar's physicochemical characteristics to their sorption behavior. The biochars prepared from quinoa residues showed much higher cadmium uptakes than the other biochars. The concentration of base cations was found to be a critical factor for cadmium sorption. Although the quinoa biochars presented large uptakes, it was found that base cations were supported on the biochars and could be removed by leaching. Results from this study suggest that concentration of base cations on biochars could be used as predictors of the biochar capabilities for the removal of cadmium in aqueous solution. Copyright © 2020 American Chemical Society.

Molecularly imprinted polymers have emerged as cost-effective and rugged artificial selective sorbents for combination with different sensors. In this study, quaternary ammonium cations, as functional monomers, were systematically evaluated to design imprinted polymers for glyphosate as an important model compound for electrically charged and highly water-soluble chemical compounds. To this aim, a small pool of monomers were used including (3-acrylamidopropyl)trimethylammonium chloride, [2-(acryloyloxy)ethyl]trimethylammonium chloride, and diallyldimethylammonium chloride. The simultaneous interactions between three positively charged monomers and glyphosate were preliminary evaluated using statistical design of the experiment method. Afterwards, different polymers were synthesized at the gold surface of the quartz crystal microbalance sensor using optimized and not optimized glyphosate-monomers ratios. All synthesized polymers were characterized using atomic force microscopy, contact angle, Fourier-transform infrared, and X-ray photoelectron spectroscopy. Evaluated functional monomers showed promise as highly efficient functional monomers, when they are used together and at the optimized ratio, as predicted by the statistical method. Obtained results from the modified sensors were used to develop a simple model describing the binding characteristics at the surface of the different synthesized polymers. This model helps to develop new synthesis strategies for rational design of the highly selective imprinted polymers and to use as a sensing platform for water soluble and polar targets. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

A detailed study on the single-molecule ferroelectric property of Preyssler-type polyoxometalates (POMs), [M3+P5W30O110](12-) (M = La, Gd, and Lu), is performed by density functional theory calculations. Linked to one H2O molecule, the cation (M3+) encapsulated in the cavity of the Preyssler framework is off-centered, and it generates a permanent dipole, which is essential for a ferroelectric ground state. Accompanied with a 180 degrees rotation of H2O, the switching of M3+ between two isoenergetic sites on both sides of the cavity results in a calculated barrier of 1.15 eV for Gd3+, leading to the inversion of electric polarization. The height of the barrier is in good agreement with the experimentally measured barrier for the Tb3+ ion, whose ionic radius is similar to Gd3+. The total polarization value of the crystal is estimated to be 4.7 mu C/cm(2) as calculated by the modern theory of polarization, which is quite close to the experimental value. Considering that the order of contributions to the polarization is M3+-H2O > counter-cations (K+) > [P5W30O110](15-), the interconversion of M3+-H2O between the two isoenergetic sites is predicted to be the main origin of ferroelectricity with a polarization contribution of 3.4 mu C/cm(2); the K+ counter-cations contribute by 1.2 mu C/cm(2) and it cannot be disregarded, while the framework appears to contribute negligibly to the total polarization. Our study suggests that a suitable choice of M3+-H2O could be used to tune the single-molecule ferroelectricity in Preyssler-type polyoxometalates.

We report on the development of a novel laser crystal with broadband emission properties at similar to 2 mu m - a Tm3+, Li+-codoped calcium tantalum gallium garnet (Tm:CLTGG). The crystal is grown by the Czochralski method. Its structure (cubic, sp. gr . la (3) over bard, a = 12.5158(0) angstrom) is refined by the Rietveld method. Tm:CLTGG exhibits a relatively high thermal conductivity of 4.33 Wm(-1) K-1. Raman spectroscopy confirms a weak concentration of vacancies due to the charge compensation provided by Li+ codoping. The transition probabilities of Tm3+ ions are determined using the modified Judd-Ofelt theory yielding the intensity parameters Omega(2) = 5.185, Omega(4) = 0.650, Omega(6) = 1.068 [10(-20) cm(2)] and alpha = 0.171 [10(-4) cm]. The crystal-field splitting of the Tm3+ multiplets is revealed at 10 K. The first diode-pumped Tm:CLTGG laser generates 1.08 W at similar to 2 mu m with a slope efficiency of 23.8%. The Tm3+ ions in CLTGG exhibit significant inhomogeneous spectral broadening due to the structure disorder (a random distribution of Ta5+ and Ga3+ cations over octahedral and tetrahedral lattice sites) leading to smooth and broad gain profiles (bandwidth: 130 nm) extending well above 2 mu m and rendering Tm:CLTGG suitable for femtosecond pulse generation. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement