Health promoting healthcare environments, from inside to outside : a case study of patients' use and experience of the Radiotherapy department in Lund, Skåne University Hospital

Utgångspunkten för denna studie var att undersöka den fysiska vårdmiljöns betydelse för patienters hälsa och välbefinnande. Dessutom fanns ett intresse av att se på vilket sätt en vårdmiljös utformning kan påverka upplevelsen och användningen av den. Studiens syfte var att undersöka patienters upplevelse och användning av den fysiska vårdmiljön på Strålbehandlingen i Lund. Detta gjordes från insidan till utsidan för att få ett helhetsgrepp om vårdmiljön, där både inomhus- och utomhusmiljön inkluderades. Undersökningen utfördes med hjälp av en evidensbaserad modell, fyra zoner av kontakt med utemiljön (Bengtsson, 2015). Denna principmodell syftar att undersöka och beskriva miljökvaliteter i alla zoner av vårdmiljön där kontakt med utemiljön finns. Modellen är avsedd att användas i designprocesser för att belysa hur planering och utformning av vårdinrättningar kan påverka omfattningen samt kvaliteten av kontakten med utemiljön. Förståelsen för brukarnas behov i relation till den fysiska vårdmiljön är central. Vidare är modellen unik då den inkluderar inomhusmiljön, som del av ett utomhusperspektiv, något som var viktigt i den här studien. Modellen består av: • Zon 1. Innemiljö i kontakt med utemiljö, genom fönster • Zon 2. Övergångszon mellan inne- och utemiljö, t.ex. entréhallar, balkonger, terrasser • Zon 3. Utemiljö i direkt anslutning till en byggnad, t.ex. tillhörande park eller trädgård • Zon 4. Yttre omgivning, dvs. omgivande landskap Frågeställningarna i arbetet bestod av följande: Kan alla fyra zoner av kontakt med utemiljön identifieras på Strålbehandlingen? Hur fungerar det att använda modellen fyra zoner av kontakt med utemiljön på Strålbehandlingen? Hur ser personalen att patienterna upplever samt använder Strålbehandlingens olika miljöer (zoner)? Hur upplever samt använder patienterna Strålbehandlingens olika miljöer (zoner)? Vilka är målgruppens specifika behov i varje zon, och hur ser sambandet mellan utformning, användning och upplevelse ut? Datainsamlingen gjordes med hjälp av modellen fyra zoner av kontakt med utemiljön i en kombination med flera olika metoder. Insamlingen av det empiriska materialet inleddes med en förundersökning (muntlig korrespondens och rundvisning). Efter det användes platsanalys, observation samt semistrukturerade intervjuer, där både fokusgrupp med personal samt individuell intervju med patient ingick. Studien var kvalitativ i sin karaktär och utgick från ett fenomenologiskt perspektiv där utgångspunkten är teorineutral, förutsättningslös och där människors upplevelser är det centrala. Det var därför viktigt att deltagarna fick tala så fritt som möjligt, för att på så sätt öppna upp för möjligheten att generera ny kunskap. Stimulusmaterial i form av fotografier samt en övergripande intervjufråga användes för att tydliggöra studiens huvudsakliga fokus. Initiala resultat visade att det fanns ett behov av att addera en extra zon till modellen fyra zoner av kontakt med utemiljön. Med Zon 0- innemiljö utan kontakt med utemiljö, kunde Strålbehandlingens alla miljöer (inomhus och utomhus) inkluderas. I studiens resultatdel presenteras fem teman som kartlägger patienters behov av den fysiska vårdmiljön i relation till de olika zonerna: Orientering och Tillgänglighet/Trygghet, Inbjudande och Behaglig/Bekväm miljö, Sysselsättning och Distraktion, Kontakt med utemiljön samt Sociala aspekter. Dessa teman visar hur patienterna upplever och använder zonerna på ett varierande sätt samt att olika miljökvaliteter är viktiga i olika delar av vårdmiljön. Patienterna har således behov och önskemål som är direkt kopplade till specifika delar av den fysiska miljön. Denna kunskap kan vara värdefull i ett designsammanhang, där förståelsen för brukarnas behov är grundläggande för en god och hälsofrämjande miljö. Ett klart samband mellan platsens utformning och patienternas användning och upplevelse av den har därmed observerats i studien. Studien visar vidare på betydelsen av att testa modeller för evidensbaserade designprocesser i olika typer av vårdmiljöer och med olika patientgrupper. Genom att använda modellen fyra zoner av kontakt med utemiljön i en ny typ av vårdmiljö (strålbehandlingsavdelning) har kunskap samlats in som kan bidra till utvecklingen av modellen och ge en fördjupad förståelse av zonerna. Dessutom kan förståelsen för patienternas behov i relation till vårdmiljöns skilda zoner gynna dialoger i designprocesser då nya vårdmiljöer planeras. Slutligen fokuserar studien på en väldigt specifik patientgrupp, cancerpatienter som genomgår strålbehandling, vilket gör att resultatet i synnerhet skulle kunna användas som underlag i designprocesser för vårdmiljöer inriktade på denna patientgrupp.The focus of this study was to investigate the physical healthcare environment and its significance for patients' health and wellbeing. Also important was whether a relationship between the design of a healthcare facility, and patients’ use and experience of that facility, could be distinguished. The aim of this study was to investigate patients' use and experience of the physical healthcare environment at the Radiotherapy department in Lund (Sweden). This was done from the inside to the outside to get an overall view of the environment, in which both the indoors and outdoors were included. Information was gathered using the evidence-based model four zones of contact with the outdoors (Bengtsson, 2015). This principal model aims holistically to include physical qualities in all areas (zones) of an environment where contact with the outdoors exists. The model is intended to be used in design processes to highlight how planning and design of healthcare facilities can affect the level and quality of contact with the outdoors. An important part is also to understand the users’ needs in relation to their physical environment. Finally, the model is unique in that it includes the indoors, as part of studying the outdoors, which was important in this study. The model consists of the following zones of contact with the outdoors: • Zone 1. From inside the building, through a window • Zone 2. Transition zone between indoors and outdoors, e.g. entrance halls, balconies and terraces • Zone 3. Immediate surroundings, e.g. associated garden or park • Zone 4. The wider neighbourhood i.e. surrounding landscape The research questions in this study thus consisted of the following: Can all four zones of contact with the outdoors be identified in the Radiotherapy department? How does it work to use the model four zones of contact at the Radiotherapy department? How would the staff describe patient’s experience and use of the different spaces (zones) at the Radiotherapy department? How do the patients experience and use the different spaces (zones) at the Radiotherapy department? What are the patient group's specific needs in each zone, and what is the relationship between the design, use and experience like? Data collection was done using the model four zones of contact in a combination with several different methods. The collection of empirical material began with a preliminary investigation (verbal correspondence and guided tour). After that the methods used were site analysis, observation and semi-structured interviews, both focus groups with staff and individual interview with a patient. The study is qualitative in its nature and had a phenomenological perspective- a neutral and unbiased approach where the human experience is central. It was crucial to view the participants as experts on the subject and let them speak freely in order to open up for the possibility of generating new knowledge. Stimulus material in the form of photographs and one comprehensive interview question was used to clarify the study and the interviews principal focus. Initial results showed that there was a need to add an extra zone to the model four zones of contact. With the addition of the new Zone 0- indoor environment without contact with the outdoors, the entire environment (indoors and outdoors) of the Radiotherapy department could be included in the study. In the result part of this study five themes were introduced. They represent patients' needs in relation to the different zones of the healthcare environment: Orientation and Accessibility/Security, Inviting and Pleasant/Comfortable environment, Preoccupation and Distraction, Contact with the outdoor environment and Social aspects. These themes show how patients use and experience the zones in different ways. Also, that distinct qualities of the physical environment are important in different parts of the healthcare environment. This means that patients have needs and preferences that are directly connected to specific parts of the physical environment. Knowledge like this can be valuable in a design context, where the understanding of users' needs are fundamental to good and supportive healthcare environment. A connection between the design of a healthcare facility and patients use and experience of it have thus been observed in this study. The study furthermore highlights the importance of testing models for evidence-based design processes in different types of healthcare environments and with different patient groups. By using the model four zones of contact with the outdoors in a new type of healthcare setting (a radiotherapy department) knowledge has been gathered that could contribute to the development of the model and further understanding of the zones. Additionally, the study suggests that understanding patients' needs in relation to the different zones of a healthcare environment can be a way to promote dialogues in the design process when new facilities are being planned. Finally, the study focuses on a very specific group of patients, cancer patients undergoing radiotherapy, which suggests that the results could be used as a basis for discussion in design processes of healthcare environments focused on the same patient group

Coordination and thermodynamic properties of aqueous protactinium(V) by first-principle calculations

Protactinium (Z = 91) is a very rare actinide with peculiar physico-chemical properties. Indeed, although one may naively think that it behaves similarly to either thorium or uranium by its position in the periodic table, it may in fact follow its own rules. Because of the quite small energy gap between its valence shells (in particular the 5f and 6d ones) and also the strong influence of relativistic effects on its properties, it is actually a challenging element for theoretical chemists. In this article, we combine experimental information, chemical arguments and standard first-principle calculations, complemented by implicit and explicit solvation, to revisit the stepwise complexation of aqueous protactinium(V) with sulfate and oxalate dianionic ligands (SO4^2- and C2O4^2-, respectively). From a methodological viewpoint, we notably conclude that it is necessary to at least saturate the coordination sphere of protactinium(V) to reach converged equilibrium constant values. Furthermore, in the case of single complexations (i.e. with one sulfate or oxalate ligand bound in the bidentate fashion), we show that it is necessary to maintain the coordination of one hydroxyl group, thought of in the [PaO(OH)]^3+ precursor, to obtain coherent complexation constants. Therefore, we predict that this hydroxyl group is maintained in the formation of 1:1 complexes while we confirm that it is withdrawn when coordinating three sulfate or oxalate ligands. Finally, we stress that this work is a first step toward the future use of theoretical predictions to elucidate the enigmatic chemistry of protactinium in solution

The effect of the environment on symptom dimensions in the first episode of psychosis: a multilevel study

Background: The extent to which different symptom dimensions vary according to epidemiological factors associated with categorical definitions of first-episode psychosis (FEP) is unknown. We hypothesized that positive psychotic symptoms, including paranoid delusions and depressive symptoms, would be more prominent in more urban environments. / Method: We collected clinical and epidemiological data on 469 people with FEP (ICD-10 F10–F33) in two centres of the Aetiology and Ethnicity in Schizophrenia and Other Psychoses (AESOP) study: Southeast London and Nottinghamshire. We used multilevel regression models to examine neighbourhood-level and between-centre differences in five symptom dimensions (reality distortion, negative symptoms, manic symptoms, depressive symptoms and disorganization) underpinning Schedules for Clinical Assessment in Neuropsychiatry (SCAN) Item Group Checklist (IGC) symptoms. Delusions of persecution and reference, along with other individual IGC symptoms, were inspected for area-level variation. / Results: Reality distortion [estimated effect size (EES) 0.15, 95% confidence interval (CI) 0.06–0.24] and depressive symptoms (EES 0.21, 95% CI 0.07–0.34) were elevated in people with FEP living in more urban Southeast London but disorganized symptomatology was lower (EES –0.06, 95% CI –0.10 to –0.02), after controlling for confounders. Delusions of persecution were not associated with increased neighbourhood population density [adjusted odds ratio (aOR) 1.01, 95% CI 0.83–1.23], although an effect was observed for delusions of reference (aOR 1.41, 95% CI 1.12–1.77). Hallucinatory symptoms showed consistent elevation in more densely populated neighbourhoods (aOR 1.32, 95% CI 1.09–1.61). / Conclusions: In people experiencing FEP, elevated levels of reality distortion and depressive symptoms were observed in more urban, densely populated neighbourhoods. No clear association was observed for paranoid delusions; hallucinations were consistently associated with increased population density. These results suggest that urban environments may affect the syndromal presentation of psychotic disorders

City dweller aspirations for cities of the future: How do environmental and personal wellbeing feature?

This paper explores city dweller aspirations for cities of the future in the context of global commitments to radically reduce carbon emissions by 2050; cities contribute the vast majority of these emissions and a growing bulk of theworld's population lives in cities. The particular challenge of creating a carbon reduced future in democratic countries is that the measures proposed must be acceptable to the electorate. Such acceptability is fostered if carbon reduced ways of living are also felt to bewellbeing maximising. Thus the objective of the paper is to explore what kinds of cities people aspire to live in, to ascertain whether these aspirations align with or undermine carbon reduced ways of living, as well as personal wellbeing. Using a novel free associative technique, city aspirations are found to cluster around seven themes, encompassing physical and social aspects. Physically, people aspire to a city with a range of services and facilities, green and blue spaces, efficient transport, beauty and good design. Socially, people aspire to a sense of community and a safe environment. An exploration of these themes reveals that only a minority of the participants' aspirations for cities relate to lowering carbon or environmental wellbeing. Far more consensual is emphasis on, and a particular vision of, aspirations that will bring personal wellbeing. Furthermore, city dweller aspirations align with evidence concerning factors that maximise personal wellbeing but, far less, with those that produce lowcarbonways of living. In order to shape a lower carbon future that city dwellers accept the potential convergence between environmental and personal wellbeing will need to be capitalised on: primarily aversion to pollution and enjoyment of communal green space

Approches combinées ab initio et par spectroscopie de luminescence résolue en temps pour l'étude des l'interactions uranium-ligand

Uranyl complexes have been the subject of many research works for fundamental chemistry of actinides, environmental issues, or nuclear fuel cycle processes. The formation of various uranium(VI) complexes, with ligands in solution must be characterized for a better understanding of U(VI) speciation. Uranyl-ligand interactions and symmetry of the complexes both affect the electronic structure of U(VI), and thus its luminescence properties. Time-resolved laser induced fluorescence spectroscopy (TRLFS) is one of the widely used techniques to get insights on the closest chemical environment of the uranyl ion in samples, owing to its high sensitivity and selectivity. However, the luminescence spectra fingerprints hold information within and beyond the first-coordination sphere of uranyl(VI), that needs to be more deeply investigated by supplementary techniques.A promising route for data interpretation consists in creating a synergy between TRLFS and ab initio-based interpretations. Luminescence spectra of uranyl complexes in solution typically show well-spaced vibronic progressions that overlap with the pure electronic transition from the excited state to the ground state. This has driven the theoretical methodology implementation. In the frame of this thesis, time-dependent density functional theory (TD-DFT) with hybrid and range-separated functionals is used to model the electronic structure of uranium(VI) complexes. This represents an effective theoretical approach with a reasonable computational cost and accuracy, compared with computationally expensive wave-function based methods, in a relativistic context. It enabled to characterize the main spectral parameters and the first low-lying excited state of uranyl compounds with different ligands and counterions after the photo-excitation, and to compute with a high accuracy the vibronic progression in order to guide the interpretation of experimental results.In particular we focused our efforts on characterizing the influence of the organic or inorganic closest chemical environment of the uranium(VI)-based complexes. We studied 1) the influence of the extracting agent such as Aliquate 336 and solvent effect on uranyl tetrahalides; 2) inorganic Ca2+ and Mg2+ counterions on uranyl triscarbonates; and 3) monoamide ligands (di-2-ethylhexyl-isobutyramide) on uranyl binitrate complexes. Their electronic structures and main spectroscopic properties have been estimated by both TRLFS and ab initio techniques. The theoretical approach enabled to calculate the main luminescence emissions of the complexes with the corresponding assignment of the electronic transitions and vibronic modes involved. For all the studied complexes, a good agreement between theory and experiment was found, allowing to build a full picture about the capabilities of the methods.Les complexes d'uranyle ont fait l'objet de nombreux travaux de recherche pour la chimie fondamentale des actinides, les enjeux environnementaux ou les procédés du cycle du combustible nucléaire. La formation de divers complexes d'uranium(VI), avec des ligands en solution doit être caractérisée pour une meilleure compréhension de la spéciation de U(VI). Les interactions uranyl-ligand et la symétrie des complexes modifient la structure électronique de U(VI) et donc ses propriétés de luminescence. La spectrofluorimétrie laser résolue en temps (SLRT) est l'une des techniques largement utilisées pour obtenir des informations sur l'environnement chimique proche de l'ion uranyle dans les échantillons, en raison de sa sensibilité et de sa sélectivité élevées. Cependant, les signatures des spectres de luminescence contiennent des informations liées à la première sphère de coordination de l'uranyle et au-delà, et méritent d'être étudiée de manière plus approfondie par des techniques adaptées.Une voie prometteuse pour l'interprétation des données consiste à créer une synergie entre SLRT et les interprétations ab initio. Les spectres de luminescence des complexes d'uranyle en solution montrent généralement des progressions vibroniques bien espacées qui se chevauchent avec la transition électronique pure provenant de l'état excité à l'état fondamental. Ceci a conduit la mise en œuvre de notre méthodologie théorique. Dans le cadre de cette thèse, la théorie fonctionnelle de la densité dépendante du temps (TD-DFT) avec des fonctionnelles hybrides et séparées par une plage est utilisée pour modéliser la structure électronique de complexes d'uranium(VI) dans un contexte relativiste. Cela a permis de caractériser les principaux paramètres spectraux et le premier état excité de plusieurs composés d'uranyle avec différents ligands et contre-ions, et de calculer avec une grande précision la progression vibronique afin de guider l'interprétation des résultats expérimentaux.En particulier, nous avons concentré nos efforts sur la caractérisation de l'influence de l'environnement chimique le plus proche des complexes à base d'uranium(VI). Nous avons étudié 1) l'influence d'un agent d'extraction tel que l'Aliquate 336 et l'effet du solvant sur les tétrahalogénures d'uranyle; 2) les contre-ions inorganiques Ca2+ et Mg2+ sur les triscarbonates d'uranyle ; et 3) les ligands monoamide (di-2-éthylhexyl-isobutyramide) sur les complexes de binitrate d'uranyle. Leurs structures électroniques et leurs principales propriétés spectroscopiques ont été estimées par les deux techniques SLRT et ab initio. L'approche théorique a permis de calculer les principales émissions de luminescence des complexes avec l'affectation correspondante des transitions électroniques et des modes vibroniques impliqués. Pour tous les complexes étudiés, un bon accord entre la théorie et l'expérience a été obtenu, permettant de construire une image plus complète des capacités des méthodes

THE SOCIOSPATIAL DISTRIBUTION OF PSYCHOTIC SYMPTOMS AND DIMENSIONS

Den sociala omgivningens påverkan på vår mentala hälsa är viktig att försöka förstå. Mycket forskning har ägnats åt att undersöka hur omgivningen påverkar antalet personer som insjuknar med olika typer av psykiatriska diagnoser. Få har dock undersökt hur omgivningen påverkar symptombilden inom psykiatriska tillstånd som till exempel psykotiska sjukdomar. Psykos är ett tillstånd som kan innefatta till exempel hallucinationer och vanföreställningar, ofta i kombination med andra psykologiska symptom. Med hjälp av data från 469 personer med förstaepisods-psykos från sydöstra London och Nottingham kunde Demjaha et al. identifiera fem huvudsakliga symptomdimensioner inom det psykotiska sjukdomsspektrumet: mani, förvrängd verklighetsuppfattning, negativa symptom, depressiva symptom samt desorganisation. Med hjälp av olika statistiska metoder undersökte vi sedan, för samma urvalsgrupp, omgivningens påverkan på dessa fem symptomdimensioner. Vi fann att nivåerna av förvrängd verklighetsuppfattning var högre i London än i Nottingham. En utökad analys antydde att denna effekt var starkare för de personer som diagnosticerats med en så kallad icke-affektiv psykotisk sjukdom (såsom schizofreni) jämfört med så kallad affektiv psykotisk sjukdom (såsom depression med psykos). Det fanns även tecken på ökad nivå av depressiva symptom i London och ökad nivå av desorganisation i Nottingham. Inga skillnader observerades för mani eller negativa symptom. Det har spekulerats att stimuli från omgivningen kan påverka risken att utveckla så kallade positiva psykotiska symptom. Vårt fynd att högre nivåer av förvrängd verklighetsuppfattning kunde identifieras i en mer urban miljö (London jämfört med Nottingham) passar väl med denna idé. Resultaten i detta arbete indikerar att denna effekt främst verkar gälla för icke-affektiva psykotiskta sjukdomstillstånd, vilket skulle kunna tyda på olika etiologiska bakgrunder (uppkomstorsaker) för icke-affektiva och affektiva sjukdomstillstånd

Approches combinées ab initio et par spectroscopie de luminescence résolue en temps pour l'étude des l'interactions uranium-ligand

Uranyl complexes have been the subject of many research works for fundamental chemistry of actinides, environmental issues, or nuclear fuel cycle processes. The formation of various uranium(VI) complexes, with ligands in solution must be characterized for a better understanding of U(VI) speciation. Uranyl-ligand interactions and symmetry of the complexes both affect the electronic structure of U(VI), and thus its luminescence properties. Time-resolved laser induced fluorescence spectroscopy (TRLFS) is one of the widely used techniques to get insights on the closest chemical environment of the uranyl ion in samples, owing to its high sensitivity and selectivity. However, the luminescence spectra fingerprints hold information within and beyond the first-coordination sphere of uranyl(VI), that needs to be more deeply investigated by supplementary techniques.A promising route for data interpretation consists in creating a synergy between TRLFS and ab initio-based interpretations. Luminescence spectra of uranyl complexes in solution typically show well-spaced vibronic progressions that overlap with the pure electronic transition from the excited state to the ground state. This has driven the theoretical methodology implementation. In the frame of this thesis, time-dependent density functional theory (TD-DFT) with hybrid and range-separated functionals is used to model the electronic structure of uranium(VI) complexes. This represents an effective theoretical approach with a reasonable computational cost and accuracy, compared with computationally expensive wave-function based methods, in a relativistic context. It enabled to characterize the main spectral parameters and the first low-lying excited state of uranyl compounds with different ligands and counterions after the photo-excitation, and to compute with a high accuracy the vibronic progression in order to guide the interpretation of experimental results.In particular we focused our efforts on characterizing the influence of the organic or inorganic closest chemical environment of the uranium(VI)-based complexes. We studied 1) the influence of the extracting agent such as Aliquate 336 and solvent effect on uranyl tetrahalides; 2) inorganic Ca2+ and Mg2+ counterions on uranyl triscarbonates; and 3) monoamide ligands (di-2-ethylhexyl-isobutyramide) on uranyl binitrate complexes. Their electronic structures and main spectroscopic properties have been estimated by both TRLFS and ab initio techniques. The theoretical approach enabled to calculate the main luminescence emissions of the complexes with the corresponding assignment of the electronic transitions and vibronic modes involved. For all the studied complexes, a good agreement between theory and experiment was found, allowing to build a full picture about the capabilities of the methods.Les complexes d'uranyle ont fait l'objet de nombreux travaux de recherche pour la chimie fondamentale des actinides, les enjeux environnementaux ou les procédés du cycle du combustible nucléaire. La formation de divers complexes d'uranium(VI), avec des ligands en solution doit être caractérisée pour une meilleure compréhension de la spéciation de U(VI). Les interactions uranyl-ligand et la symétrie des complexes modifient la structure électronique de U(VI) et donc ses propriétés de luminescence. La spectrofluorimétrie laser résolue en temps (SLRT) est l'une des techniques largement utilisées pour obtenir des informations sur l'environnement chimique proche de l'ion uranyle dans les échantillons, en raison de sa sensibilité et de sa sélectivité élevées. Cependant, les signatures des spectres de luminescence contiennent des informations liées à la première sphère de coordination de l'uranyle et au-delà, et méritent d'être étudiée de manière plus approfondie par des techniques adaptées.Une voie prometteuse pour l'interprétation des données consiste à créer une synergie entre SLRT et les interprétations ab initio. Les spectres de luminescence des complexes d'uranyle en solution montrent généralement des progressions vibroniques bien espacées qui se chevauchent avec la transition électronique pure provenant de l'état excité à l'état fondamental. Ceci a conduit la mise en œuvre de notre méthodologie théorique. Dans le cadre de cette thèse, la théorie fonctionnelle de la densité dépendante du temps (TD-DFT) avec des fonctionnelles hybrides et séparées par une plage est utilisée pour modéliser la structure électronique de complexes d'uranium(VI) dans un contexte relativiste. Cela a permis de caractériser les principaux paramètres spectraux et le premier état excité de plusieurs composés d'uranyle avec différents ligands et contre-ions, et de calculer avec une grande précision la progression vibronique afin de guider l'interprétation des résultats expérimentaux.En particulier, nous avons concentré nos efforts sur la caractérisation de l'influence de l'environnement chimique le plus proche des complexes à base d'uranium(VI). Nous avons étudié 1) l'influence d'un agent d'extraction tel que l'Aliquate 336 et l'effet du solvant sur les tétrahalogénures d'uranyle; 2) les contre-ions inorganiques Ca2+ et Mg2+ sur les triscarbonates d'uranyle ; et 3) les ligands monoamide (di-2-éthylhexyl-isobutyramide) sur les complexes de binitrate d'uranyle. Leurs structures électroniques et leurs principales propriétés spectroscopiques ont été estimées par les deux techniques SLRT et ab initio. L'approche théorique a permis de calculer les principales émissions de luminescence des complexes avec l'affectation correspondante des transitions électroniques et des modes vibroniques impliqués. Pour tous les complexes étudiés, un bon accord entre la théorie et l'expérience a été obtenu, permettant de construire une image plus complète des capacités des méthodes

Design and simulation of thermal systems, international edition/ Suryanarayana

xiv, 530 hal.: ill.; 23 cm

Chemistry and speciation of protactinium – a first principles study

National audienceIt is of fundamental interest to understand and predict the chemistry of rare radioelements. In this work, we focus on protactinium (Z = 91), an element that is sandwiched in between thorium and uranium in the periodic table. Protactinium may naturally occur in environment (protactini-um-231 results from the decay of naturally occurring uranium-235) and also appear in thorium-based nuclear fuel cycles. From a chemical point of view, protactinium is a crossing point in the actinide series [1] and its chemistry is hard to predict [2,3]. We hypothesize that relativistic quantum chemistry should allow us to understand the enigmatic chemistry of protactinium and even predict it. For our first study, we have chosen to focus on the coordination sphere of protactinium and on the computation of equilibrium constants for experimentally known systems [3–5]. The occur-rence of 1:1, 1:2 and 1:3 complexes of protactinium(V) with sulfate and oxalate ligands is thus studied by means of quantum mechanical calculations, in particular based on density functional theory. The solvent effects, inherent to solution chemistry, are introduced by means of a polariz-able continuum model [6] and the explicit treatment of water molecules (micro solvation).The coordination sphere of protactinium has been obtained by geometry optimizations per-formed both in the gas phase and in solution. It involves an oxygen atom from the Pa=O mono-oxo bond and also oxygen atoms from the bidentate ligands, and in some cases from additional water molecules. The computation of equilibrium constants and comparison with experimental data is more subtle. First, only apparent constants were experimentally determined. Since the oc-currence of a mono-oxo bond was confirmed by EXAFS [5] even in the case of the 1:3 complex with oxalate ligands (corresponding to the stronger complexation), we hypothesize that this bond is also present in all the studied complexes. Second, number of explicitly treated water molecules should not be randomly chosen, it should ideally (i) lead to saturation of the coordination sphere of protactinium and (ii) be sufficient to stabilize the anionic ligands. We find that adding CN+1 water molecules is enough to satisfy both conditions in all the six studied complexes. By doing so and computing ligand-exchange equilibrium constants, we reproduce well the experimental trends for the exchange of 2 and 3 ligands, while the exchange of only one ligand (1:1 complex-es) is still hard to reproduce from computations.We report recent progress concerning the basic chemistry of protactinium. We have shown that its coordination sphere may include up to 8 oxygen atoms (from the original mono-oxo bond and from ligand and solvent molecule complexation) and find an approximate way of determin-ing trends in equilibrium constants, opening the way for future predictions.[1]Wilson R. et al. (2018) Nat. Commun. 9, 622.[2]Wilson R. (2012) Nat. Chem. 4, 586.[3]Le Naour C. et al. (2019) Radiochim. Acta, 107, 979-991.[4]Le Naour C. et al. (2005) Inorg. Chem. 44, 9542.[5]Mendes M. et al. (2010) Inorg. Chem. 49, 9962-9971.[6]Barone et al. (1997) J. Chem. Phys. 107, 3210-3221.<br

Chemistry, spectroscopy and speciation of protactinium

International audienc