Diss. (sammanfattning) Linköping : Univ., 2002. / Härtill 5 uppsatser.

The present thesis is a theoretical study of several x-ray spectroscopies { x-ray absorption, xray photoelectron, radiative and non-radiative resonant Raman scattering spectroscopy. The main focus point is investigating the role of the nuclear dynamics in molecules (naphthalene, biphenyl, the water dimer, HCl) on these spectra. The theoretical tools we use consist of the basic equations of the relevant x-ray spectroscopy. Wave packet methods are also used. The molecular parameters needed for our simulations are obtained through suitable quantum chemical calculations, mainly based on either wave function or density functional methods. Our simulations are compared with experimental data, where available. Simulations of x-ray absorption and x-ray photoionization spectra for naphthalene and biphenyl show that the spectral shapes are heavily inuenced by the joint e ect of two factors { chemical shifts and excitations of vibrational progression. In both of the studied molecules, similar vibrational modes are excited, giving rise to a signi cant vibrational broadening of the spectra. Comparison between the two molecules and also comparison to the reference case { benzene, provides useful insight into the molecular behavior under core excitation. In a further step, we consider the O1s x-ray photoelectron spectrum of the water dimer. A substantial broadening of the two bands originating from the donor and the acceptor oxygen is found. It is caused by excitations of soft intermolecular vibrational modes, associated with the hydrogen bond. Another strong inuence of the nuclear dynamics is clearly seen in the resonant x-ray Raman scattering of HCl. Vibrational collapse is observed experimentally and con rmed theoretically for two cases: resonant excitation of the K line and o -resonant excitation of the elastic peak. These two collapses can be strictly realized for excitations in the hard x-ray region. Our considerations show that using this technique, one can eliminate the broadenings caused by the lifetime of the core excited state and the vibrational broadening, and hence, considerably increase the spectral resolution. Finally, we predict an interference e ect in the resonant Auger scattering from xed-inspace molecules. By exciting a molecule to a dissociative state and measuring the angular distribution of the Auger electrons in coincidence with the molecular ion, one can observe this e ect. The interference pattern can be used after Fourier transformation for extracting structural data about the studied system. / QC 20101215

This licentiate thesis deals with quantum chemistry methods for large systems. In particular, the thesis focuses on the efficient construction of the Coulomb and exchange matrices which are important parts of the Fock matrix in Hartree--Fock calculations.The methods described are also applicable in Kohn--Sham Density FunctionalTheory calculations, where the Coulomb and exchange matrices areparts of the Kohn--Sham matrix. Screening techniques for reducing the computational complexity of bot Coulomb and exchange computations are discussed, as well as the fast multipole method, used for efficient computation of the Coulomb matrix. The thesis also discusses how sparsity in the matrices occurring in Hartree--Fock and Kohn--Sham Density Functional Theory calculations can be used to achieve more efficient storage of matrices as well as more efficient operations on them. As an example of a possible type of application, the thesis includes a theoretical study of Heisenberg exchange constants, using unrestricted Kohn--Sham Density Functional Theory calculations. / QC 20101123

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<p>This essay is a study that takes interest in technical and technological change essential to philosophy of science. What is shown is the importance of an active attitude towards this change, by the articulation of the question: Does technical development lead to new ontological questions for science? - and by the answer that such questions do appear.</p><p>It is clear that passive assumptions in this matter might prohibit science in the proceeding search for truth.</p><p>By examples of ways in which technical development helps and challenges science, it is concluded that scrutiny of the relationship between technical development and ontological suppositions and hypotheses within science is well motivated.</p> / <p>Denna uppsats är en studie vilken intresserar sig för teknisk och teknologisk förändring essentiell för vetenskapsfilosofi. Det som påvisas är betydelsen av ett aktivt förhållningssätt till denna förändring, genom formuleringen av frågan: Leder teknisk utveckling till nya ontologiska frågor för vetenskapen? - och genom svaret att sådana frågor uppstår.</p><p>Det framgår att passiva antaganden angående detta kan förhindra vetenskapen i det fortskridande sanningssökandet.</p><p>Genom exempel på sätt som teknisk utveckling hjälper och utmanar vetenskapen, framträder slutsatsen att granskning av förhållandet mellan teknisk utveckling och de ontologiska antagandena och hypoteserna inom vetenskapen är väl motiverad.</p>

This essay is a study that takes interest in technical and technological change essential to philosophy of science. What is shown is the importance of an active attitude towards this change, by the articulation of the question: Does technical development lead to new ontological questions for science? - and by the answer that such questions do appear. It is clear that passive assumptions in this matter might prohibit science in the proceeding search for truth. By examples of ways in which technical development helps and challenges science, it is concluded that scrutiny of the relationship between technical development and ontological suppositions and hypotheses within science is well motivated. / Denna uppsats är en studie vilken intresserar sig för teknisk och teknologisk förändring essentiell för vetenskapsfilosofi. Det som påvisas är betydelsen av ett aktivt förhållningssätt till denna förändring, genom formuleringen av frågan: Leder teknisk utveckling till nya ontologiska frågor för vetenskapen? - och genom svaret att sådana frågor uppstår. Det framgår att passiva antaganden angående detta kan förhindra vetenskapen i det fortskridande sanningssökandet. Genom exempel på sätt som teknisk utveckling hjälper och utmanar vetenskapen, framträder slutsatsen att granskning av förhållandet mellan teknisk utveckling och de ontologiska antagandena och hypoteserna inom vetenskapen är väl motiverad.

This thesis reports a state-of-the-art theoretical study of photophysical properties of organic charge-transfer aromatic molecules. These molecules are building blocks of molecular functional materials used in modern photonics technology and play essential roles in chemistry and biology in general. A good understanding of these systems is thus important. The theoretical results for permanent dipole moments of some substituted benzenes have been obtained using the coupled cluster singles and doubles (CCSD) method. The performance of density functional theory (DFT) for the geometry and electronic properties has been compared with that of traditional ab initio methods, such as Hartree-Fock, second-order Möller Plesset perturbation theory (MP2), CCSD and CCSD(T). Limitations of the DFT methods for charge transfer molecules have been demonstrated. The multi-configuration self-consistent field (MCSCF) method has been applied to understand properties of the triplet states of benzene derivatives by studying their phosphorescence with the inclusion of contributions from vibronic coupling. It has also been employed to calculate the photophysics of the thioxanthone molecule containing three benzene rings in combination with the CASPT2 method, resolving a long-standing problem concerning the possible stable conformations of the molecule. With knowledge of the building blocks a series of porphyrin derivatives with exceptionally large two-photon absorption cross sections were designed, and proposed for use in bioimaging applications. The static and dynamic properties of a few zinc and platinum organometallic compounds, being possible candidates for optical limiting devices, have also investigated. / QC 20101011

<p>The spin of an electron often misleadingly interpreted as the classical rotationof a particle. The quantum spin distinguishes itself from classicalrotation by possessing quantized states and can be detected by its magneticmoment. The properties of spin and its collective behavior with otherfundamental properties are fascinating in basic sciences. In many aspectsit offers scope for designing new materials by manipulating the ensemblesof spin. In recent years attention towards high density storage devices hasdriven the attention to the fundamental level were quantum physics rules.To understand better design of molecule based storage materials, studies onspin degrees of freedom and their coupling properties can not be neglected.</p><p>To account for many body effect of two or more electrons consistent withrelativity, an approximation like the Breit Hamiltonian(BH) is used in modernquantum chemical calculations, which is successful in explaining the splitin the spectra and corresponding properties associated with it. Often differenttactics are involved for a specific level of computations. For example themulti-configurational practice is different from the functional based calculations,and it depends on the size of the system to choose between resourcesand accuracy. As the coupling terms offers extra burden of calculating theintegrals it is literally challenging.</p><p>One can readily employ approximations as it suits best for the applicationoriented device computations. The possible methods available in the literatureare presented in chapter 2. The theoretical implementations of couplingfor the multi-reference and density functional method are discussed in detail.The multi-reference method precedes the density functional methodin terms of accuracy and generalizations, however it is inefficient in dealingvery large systems involving many transition elements, which is vital formolecule based magnets as they often possess open shell manifolds. On theother hand existing density functional method exercise perturbations techniqueswhich is extremely specialized for a specific system - highly coupledspins.</p><p>The importance of spin-spin coupling(SSC) in organic radical-Oxyallyl(OXA)was systematically studied with different basis sets and compared with asimilar isoelectronic radical(TMM). The method of spin-spin coupling implementationsare also emphasized. Similar coupling studies were carriedivout for the species HCP and NCN along with spin-orbit coupling(SOC).The splitting of the triplet states are in good agreement with experiments</p>

I och med att den nya läroplanen för gymnasieskolan togs i bruk år 2011 har det blivit större fokus på att tydliggöra kunskapsobjekten där ämnet idrott och hälsa ska erbjuda kunskaper om såväl som i och genom undervisningen. Undervisningen ska därmed syfta till en ökad medvetenhet och djupare förståelse i ämnet. Som en konsekvens av detta har det sedan Gy11 blivit större fokus på reflektion i undervisningen. Mot denna bakgrund är syftet med denna studie att undersöka hur lärare stimulerar till reflektion bland eleverna, och hur lärarna använder sig utav olika typer av feedback för att främja reflektion hos eleverna. Observationsstudier användes där tre lärare observerades under totalt 14 lektioner. Under observationerna framkom det med tydlighet att de reflekterande momenten inte ägde rum så ofta. Vid några av lektionerna visar studien att reflektion iscensatt av läraren inte alls var förekommande eller mycket sparsamt. De gånger stimulans till reflektion skedde så visade det sig oftast vara i samband med neutrala yttranden från läraren till eleverna. Sammanfattningsvis indikerar studien att den aktivitetsdiskurs som dominerar undervisningen verkar begränsa lärares möjligheter att skapa ett reflekterande förhållningssätt i ämnet.

Den här studien handlar om olikheter inom klassens ram. Studiens forskningsansats var mixed metod. Data samlades in via en enkät och intervjuer. I studien undersöktes lärares stundtals utmanande vardag i klassrum där de behöver förhålla sig till hela klassens behov och enskilda elevernas behov samtidigt. Syftet med studien var att undersöka hur några lärare beskriver hur de identifierar, bemöter och agerar utifrån spridningar av behov och förutsättningar i en klass (från teoretiskt svagt begåvade till särbegåvade elever) samt vilket (specialpedagogisk) stöd som dessa lärare ger, får och behöver i form av handledning eller särskilt stöd till enskilda elever i undervisningsgruppen. Studiens resultat visade att lärarna, speciallärarna och specialpedagogerna var medvetna om olikheter i klassrum och att det kan vara en utmaning och möjlighet. Studiens resultat visade även att lärarna uppfattade det svårt att skilja mellan högpresterande och särbegåvade elever. I studien framkom dessutom att särbegåvade elever fungerade som hjälplärare. Förutom detta visade resultatet att lärarna erhöll mer specialpedagogiskt stöd, via handledning och i direkta stödinsatser till individuella elever i deras grupp, gällande elever med teoretiskt svag begåvning, än vad gäller särbegåvade elever. Lärarna menade att det var svårare att välja ut, planera och implementera stödinsatser för teoretiskt svagt begåvade elever än för särbegåvade elever. Studien indikerar att lärare behöver mer specialpedagogisk handledning för att kunna bemöta olikheter inom klassens ram.