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  • 51.
    Andersson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Fysikundervisningens didaktik.
    Acquisition of a collection in context: A case study of the Uppsala Cabinet of Physics2006Inngår i: Proceedings of the XXV Scientific Instrument Symposium: East and West, The Common European Heritage / [ed] Ewa Wyka, Maciej Kluza, Anna Karolina Zawada, 2006Konferansepaper (Fagfellevurdert)
  • 52.
    Andersson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen, Fysikundervisningen didaktik.
    Conference as examination: Meeting a professional scientist culture2008Konferansepaper (Annet vitenskapelig)
  • 53.
    Andersson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Fysikundervisningens didaktik.
    Experimentalfysiken - Motiven bakom 1700-talets förändrade fysikundervisning2007Annet (Annet (populærvitenskap, debatt, mm))
  • 54.
    Andersson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Fysikundervisningens didaktik.
    'Fysikshow?' eller 'Varför måste fysik alltid vara så roligt?'2007Inngår i: Presentation at "Fysikdagarna 2007", Uppsala Universitet, 29-30 October., 2007Konferansepaper (Annet (populærvitenskap, debatt, mm))
  • 55.
    Andersson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Fysikundervisningens didaktik.
    Hur ger man civilingenjörsstudenter positiva upplevelser av utbildningens första termin?2008Konferansepaper (Annet vitenskapelig)
  • 56.
    Andersson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen, Fysikundervisningen didaktik.
    Hur tänker studenterna? Växelspelet mellan individer och utbildningsdiskursen.2008Annet (Annet vitenskapelig)
  • 57.
    Andersson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Fysikundervisningens didaktik.
    Physics Education in Sweden: An Overview2008Inngår i: Presentation at the European Committee for Future Accelerators R-ECFA Meeting, Uppsala, Sweden, 9-10 May, 2008Konferansepaper (Annet vitenskapelig)
  • 58.
    Andersson, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Fysikundervisningens didaktik.
    Undervisning och lärande ur ett identitetsperspektiv2008Inngår i: Presentation to the 'Mentorskollegiet', Uppsala University, 16 October, 2008Konferansepaper (Annet vitenskapelig)
  • 59.
    Andersson, Staffan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Fysikundervisningens didaktik.
    Elmgren, Maja
    Uppsala universitet.
    Betydelsen av den första terminen2008Inngår i: Presentation at the "Förstaårskonferens", Uppsala, Sweden, 25 May, 2008Konferansepaper (Annet (populærvitenskap, debatt, mm))
  • 60.
    Andersson, Staffan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Fysikundervisningens didaktik.
    Gelin, Birgitta
    Uppsala universitet, Universitetsförvaltningen.
    Avhopp från utbildningar i naturvetenskap och teknik vid Uppsala universitet2008Rapport (Annet vitenskapelig)
  • 61.
    Andersson, Staffan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Fysikundervisningens didaktik.
    Linder, Cedric
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Fysikundervisningens didaktik.
    Motives and Achievements of First Year Students in Bologna Physics Programmes at Uppsala University, Sweden2008Inngår i: Poster presented at the European Physics Education Network's (EUPEN) 10th Jubilee General Forum, Polana Brasov, Romania, 4-6 September, 2008Konferansepaper (Annet vitenskapelig)
  • 62.
    Andersson, Staffan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Fysikundervisningens didaktik.
    Linder, Cedric
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Fysikundervisningens didaktik.
    Motives and achievements of first year students in the masters programme in Engineering Physics at Uppsala University2008Inngår i: Paper presented at the Engineering Education Development Conference, Royal Institute of Technology, Stockholm, Sweden, 26-27 November., 2008Konferansepaper (Fagfellevurdert)
  • 63.
    Andersson, Staffan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Fysikundervisningens didaktik.
    Linder, Cedric
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Fysikundervisningens didaktik.
    Relations between motives, academic achievement and retention in the first year of a master programme in Engineering Physics2009Inngår i: Paper presented at the ESERA (European Science Education Research Association) Conference, Istanbul, Turkey, 31 August - 4 September, 2009Konferansepaper (Fagfellevurdert)
  • 64. Andreeva, M. A.
    et al.
    Monina, N.G.
    Häggström, Lennart
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Materialfysik.
    Lindgren, Bengt
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Materialfysik.
    Kalska, B.
    Kamali, M
    Vdovichev, S. N
    Salashchenko, N. N.
    Semenov, V. G
    Leupold, O
    Rüffer, R
    Nuclear resonant reflectivity with standing waves for the investigation of a thin 57Fe layer buried inside a superconducting Si/[Mo/Si]45/57Fe/Nb multilayer2008Inngår i: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 266, nr 1, s. 187-196Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A special multilayer sample Si/[Mo/Si]45/57Fe/Nb has been prepared for the depth selective investigations of the hyperfine fields in thin iron layer at low temperatures above and below the superconducting transition in the top Nb layer (Tc 8 K) by means of the nuclear resonant reflectivity with standing waves. The periodic multilayer [Mo/Si]45 below the iron layer in our sample was used as “a standing wave generator”. A weak magnetic hyperfine splitting in the 57Fe layer was detected just at low temperature. A slight variation of the nuclear resonant reflectivity time spectra measured above and below Tc was observed. At first it was supposed that this change of the spectrum shape is caused by the spatial modulation of ferromagnetic domains in the 57Fe layer caused by a proximity effect. A closer analysis, however, reveals that the spectrum variations are due to just the changes of the relative weights of the magnetic and paramagnetic phases in 57Fe layer.

  • 65.
    Arapan, Sergiu
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Understanding Physical Reality via Virtual Experiments2008Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    In this thesis I have studied some problems of condensed matter at high pressures and temperatures by means of numerical simulations based on Density Functional Theory (DFT).

    The stability of MgCO3 and CaCO3 carbonates at the Earth's mantle conditions may play an important role in the global carbon cycle through the subduction of the oceanic crust. By performing ab initio electronic structure calculations, we observed a new high-pressure phase transition within the Pmcn structure of CaCO3. This transformation is characterized by the change of the sp-hybridization state of carbon atom and indicates a change to a new crystal-chemical regime. By performing ab initio Molecular Dynamics simulations we show the new phase to be stable at 250 GPa and 1000K. Thus, the formation of sp3 hybridized bonds in carbonates can explain the stability of MaCO3 and CaCO3 at pressures corresponding to the Earth's lower mantle conditions. We have also calculated phase transition sequence in CaCO3, SrCO3 and BaCO3, and have found that, despite the fact that these carbonates are isostructural and undergo the same type of aragonite to post-aragonite transition, their phase transformation sequences are different at high pressures.

    The continuous improvement of the high-pressure technique led to the discovery of new composite structures at high pressures and complex phases of many elements in the periodic table have been determined as composite host-guest incommensurate structures. We propose a procedure to accurately describe the structural parameters of an incommensurate phase using ab initio methods by approximating it with a set of analogous commensurate supercells and exploiting the fact that the total energy of the system is a function of structural parameters. By applying this method to the Sc-II phase, we have determined the incommensurate ratio, lattice parameters and Wyckoff positions of Sc-II in excellent agreement with the available experimental data. Moreover, we predict the occurrence of an incommensurate high-pressure phase in Ca from first-principle calculations within this approach.

    The implementation of DFT in modern electronic structure calculation methods proved to be very successful in predicting the physical properties of a solid at low temperature. One can rigorously describe the thermodynamics of a crystal via the collective excitation of the ionic lattice, and the ab initio calculations give an accurate phonon spectra in the quasi-harmonic approximation. Recently an elegant method to calculate phonon spectra at finite temperature in a self-consistent way by using first principles methods has been developed. Within the framework of self-consistent ab initio lattice dynamics approach (SCAILD) it is possible to reproduce the observed stable phonon spectra of high-temperature bcc phase of Ti, Zr and Hf with a good accuracy. We show that this method gives also a good description of the thermodynamics of hcp and bcc phases of Ti, Zr and Hf at high temperatures, and we provide a procedure for the correct estimation of the hcp to bcc phase transition temperature.

  • 66.
    Arapan, Sergiu
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Mao, Ho-kwang
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Prediction of incommensurate crystal structure in Ca at high pressure2008Inngår i: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 105, nr 52, s. 20627-20630Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ca shows an interesting high-pressure phase transformation sequence, but, despite similar physical properties at high pressure and affinity in the electronic structure with its neighbors in the periodic table, no complex phase has been identified for Ca so far. We predict an incommensurate high-pressure phase of Ca from first principle calculations and describe a procedure of estimating incommensurate structure parameters by means of electronic structure calculations for periodic crystals. Thus, by using the ab initio technique for periodic structures, one can get not only reliable information about the electronic structure and structural parameters of an incommensurate phase, but also identify and predict such phases in new elements.

  • 67.
    Arapan, Sergiu
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Materialteori.
    Skorodumova, Natalia V.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Materialteori.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Materialteori.
    Determination of the Structural Parameters of an Incommensurate Phase from First Principles: The Case of Sc-II2009Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 102, nr 8, s. 085701-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We propose a procedure to accurately describe the structural parameters of an incommensurate phase using ab initio methods by approximating it with a set of analogous commensurate supercells. We apply this approach to obtain the structural parameters of the Sc-II phase, which has recently been identified as a complex incommensurate structure similar to Sr-V. The calculated incommensurate ratio gamma, lattice parameters, and Wyckoff positions of Sc-II are in excellent agreement with the available experimental data. Our results show that gamma increases with pressure up to 60 GPa approaching but never reaching the commensurate value 4/3. Hence calculations do not confirm the prediction made based on the reanalyzing of experimental data. When pressure exceeds 70 GPa, gamma shows a sharp decrease that might be considered as the precursor of a new structural phase transition.

  • 68.
    Araujo, Moyses
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Blomqvist, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Scheicher, Ralph H.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Chen, Ping
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Superionicity in the hydrogen storage material Li2NH: Molecular dynamics simulations2009Inngår i: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 79, nr 17, s. 172101-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We have employed ab initio molecular dynamics simulations in an attempt to study a temperature-induced order-disorder structural phase transformation that occurs in Li2NH at about 385 K. A structural phase transition was observed by us in the temperature range 300-400 K, in good agreement with experiment. This transition is associated with a melting of the cation sublattice (Li+), giving rise to a superionic phase, which in turn is accompanied by an order-disorder transition of the N-H bond orientation. The results obtained here can contribute to a better understanding of the hydrogen storage reactions involving Li2NH and furthermore broaden its possible technological applications toward batteries and fuel cells.

  • 69.
    Araújo, C. Moysés
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Ahuja, Rajeev
    Electronic and optical properties of pressure induced phases of MgH22005Inngår i: J. Alloys and Compd., Vol. 404-406, nr 220Artikkel i tidsskrift (Fagfellevurdert)
  • 70.
    Araújo, C. Moysés
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Ahuja, Rajeev
    Guillén, J. M. Osorio
    Jena, Puru
    Role of titanium in hydrogen desortiption in crystalline sodium Alanate2005Inngår i: Appl. Phys. Lett., Vol. 86, nr 251913, s. 3-Artikkel i tidsskrift (Fagfellevurdert)
  • 71.
    Araújo, C. Moysés
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Ahuja, Rajeev
    Talyzin, A. V.
    Sundqvist, B.
    Pressure-induced structural phase transition in NaBH42005Inngår i: Phys. Rev. B., Vol. 72, nr 054125Artikkel i tidsskrift (Fagfellevurdert)
  • 72.
    Araújo, C. Moysés
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Blomqvist, Andreas
    Scheicher, Ralph H.
    Ahuja, Rajeev
    Structural transition in lithium imide triggered by melting of cation sublatticeInngår i: Phys. Rev. Lett.Artikkel i tidsskrift (Fagfellevurdert)
  • 73.
    Araújo, C. Moysés
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Ferreira da Silva, A.
    Ahuja, Rajeev
    Pressure-induced phase transition in ErH32004Inngår i: Phys. Stat. Sol. (c), Vol. 241, nr 3219Artikkel i tidsskrift (Fagfellevurdert)
  • 74.
    Araújo, C. Moysés
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Lebegue, S.
    Eriksson, O.
    Arnaud, B.
    Alouani, M.
    Ahuja, Rajeev
    Electronic and optical properties of α, γ and β phases of MgH2: a first-principle GW investigation2005Inngår i: J. Appl. Phys., Vol. 98, nr 096106Artikkel i tidsskrift (Fagfellevurdert)
  • 75.
    Araújo, C. Moysés
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Li, Sa
    Ahuja, Rajeev
    Jena, Puru
    Vacancy-mediated hydrogen desorption in NaAlH42005Inngår i: Phys. Rev. B, Vol. 72, nr 165101Artikkel i tidsskrift (Fagfellevurdert)
  • 76.
    Arhammar, C
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Araujo, Moyses
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Energetics of Al doping and intrinsic defects in monoclinic and cubic zirconia: First-principles calculations2009Inngår i: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 80, nr 11, s. 115208-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    First-principles theory within the supercell approach has been employed to investigate Al doping and intrinsic defects in monoclinic and cubic zirconia. The effect of oxygen chemical potential and Fermi level on the formation energy and on the defect concentration have been taken into account. The formation of oxygen vacancies is found to be energetically more favorable in the cubic than in the monoclinic phase under the same oxygen chemical potential and Fermi energy. In both phases, substitutional Al decays from neutral charge state into the charge state -1, with the transition energy just above to the top of the valence band. Our findings indicate that by confining the Fermi energy to the region between the middle of the band gap and the bottom of the conduction band, high Al solubility could be achieved, although formation of Al is likely followed by the formation of interstitial oxygen. Furthermore, the concentration of Al with charge state -1 along with the equilibrium Fermi energy have been calculated in a self-consistent procedure. Here, the possible compensating defects with the relevant charge states have been considered. The obtained concentrations of Al and oxygen vacancies follow the experimental trend but underestimates experimental data. When the formation of defect clusters, composed by two substitutional Al and one oxygen vacancy, are considered, good quantitative agreement with experimental values of both Al and oxygen vacancy concentration is achieved. The results suggest that defect clusters will be formed as a result of Al doping in cubic phase of ZrO2, whereas the concentration of defect clusters is negligible in the monoclinic phase, both in accordance with experiment.

  • 77. Aryal, M. M.
    et al.
    Mishra, D. R.
    Paudyal, D. D.
    Byahut, S.
    Maharjan, N. B.
    Adhikari, N. P.
    Scheicher, Ralph H.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Materialteori.
    Jeong, Junho
    Badu, S. R.
    Pink, R. H.
    Chow, Lee
    Das, T. P.
    Understanding of nuclear quadrupole interactions of Cl-35, Br-79 and I-129 and binding energies of solid halogens at first-principles level2007Inngår i: Hyperfine Interactions, ISSN 0304-3843, E-ISSN 1572-9540, Vol. 176, nr 1-3, s. 51-57Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper deals with the understanding at a first-principles level of the nuclear quadrupole interaction (NQI) parameters of solid chlorine, bromine and iodine as well as the intermolecular binding of these molecules in the solid. The electronic structure investigations that we have carried out to study these properties of the solid halogens are based on the Hartree-Fock Cluster approach using the Roothaan variational procedure with electron correlation effects included using many-body perturbation theory with the empty orbitals used in the perturbation theory investigations for the excited states. The results of our investigations provide good agreement with the measured NQI parameters primarily from the Hartree-Fock one electron wave-functions with many-body effects making minor contributions. The binding (dissociation) energies for the molecules with the solid state environment on the other hand arises from intermolecular many body effects identified as the Van der Waals attraction with one-electron Hartree-Fock contribution being repulsive in nature.

  • 78. Asker, C
    et al.
    Vitos, Levente
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Abrikosov, I. A.
    Elastic constants and anisotropy in FeNi alloys at high pressures from first-principles calculations2009Inngår i: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 79, nr 21, s. 214112-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The single-crystal and polycrystalline elastic constants and the elastic anisotropy in face-centered cubic and hexagonal close-packed FeNi alloys have been investigated at ultrahigh pressures by means of first-principles calculations using the exact muffin-tin orbitals method and the coherent-potential approximation. Comparisons with earlier calculations for pure Fe and experimental results are presented and discussed. We show that Ni alloying into Fe increases slightly the density and has very little effect on bulk moduli. Moreover, the relative decrease in c(44) elastic constant is much stronger in the hcp phase than in the fcc one. It is found that the elastic anisotropy is higher for face-centered cubic than for the hexagonal close-packed structure of FeNi, even though the face-centered cubic phase has a higher degree of symmetry. The anisotropy in face-centered cubic structure decreases with increasing nickel concentration while a very weak increase is observed for the hexagonal close-packed structure.

  • 79.
    Avendano, Esteban
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Rensmo, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Azens, A
    Sandell, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Azevedo, G. de M.
    Siegbahn, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Niklasson, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Granqvist, Claes Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Coloration Mechanism in Proton-Intercalated Electrochromic Hydrated NiOy and Ni1-xVxOy Thin Films2009Inngår i: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 156, nr 8, s. p132-p138Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Electrochromic (EC) films of nickel oxide, with and without vanadium,   were prepared by reactive dc magnetron sputtering. They were   characterized by electrochemical and optical measurements and studied   by X-ray photoelectron spectroscopy (PES) using synchrotron radiation.  The films were analyzed under as-deposited conditions and after   bleaching/coloration by insertion/extraction of protons from a basic   solution and ensuing charge stabilization. Optical measurements were consistent with a coloration process due to charge-transfer transitions   from Ni2+ to Ni3+ states. The PES measurements showed a higher   concentration of Ni3+ in the colored films. Moreover, two peaks were   present in the O 1s spectra of the bleached film and pointed to contributions of Ni(OH)(2) and NiO. The changes in the O 1s spectra   upon coloration treatment indicate the presence of Ni2O3 in the colored   film and necessitated an extension of the conventional model for the   mechanism of EC coloration. The model involves not only proton   extraction from nickel hydroxide to form nickel oxyhydroxide but also participation of NiO in the coloration process to form Ni2O3.

  • 80. Aziz, Emad F
    et al.
    Gråsjö, Johan
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för farmaci.
    Forsberg, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Andersson, Egil
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Söderström, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Duda, Laurent
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Zhang, Wenhua
    Yang, Jinglong
    Eisebitt, Stefan
    Bergström, Christel
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för farmaci.
    Luo, Yi
    Nordgren, Joseph
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Yt- och gränsskiktsvetenskap.
    Eberhardt, Wolfgang
    Rubensson, Jan-Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Photoinduced Formation of N2 Molecules in Ammonium Compounds2007Inngår i: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 111, nr 39, s. 9662-9669Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Via fluorescence yield (FY) and resonant inelastic scattering spectroscopy in the soft X-ray range we find that soft X-rays induce formation of N2 molecules in solid NH4Cl and in related compounds. The nitrogen molecules form weak bonds in NH4Cl, so that a substantial fraction of the molecules remains in the sample. From measurements of the FY as a function of exposure and temperature, the rates for the photochemical processes are estimated. At elevated temperatures (363 K), several nitrogen atoms are removed from the sample per incoming photon. At lower temperatures (233 K), the rate is reduced to around 0.02 nitrogen atoms for each incoming photon. Virtually all these atoms form N2 molecules which are bound in the sample. The generality and implications of these results are briefly discussed.

  • 81. Aziz, Emad F
    et al.
    Ottosson, Niklas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Bonhommeau, Sébastien
    Bergmann, Nora
    Eberhardt, Wolfgang
    Chergui, Majed
    Probing the electronic structure of the hemoglobin active center in physiological solutions.2009Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 102, nr 6, s. 068103-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Soft-x-ray absorption spectroscopy at the L_{2,3} edge of the iron center in bovine hemoglobin and hemin under physiological conditions is reported for the first time. Spectra of the same compounds in solid form are presented for comparison. Striking differences in the electronic structure of the metalloporphyrin are observed between the liquid and solid compounds. We unambiguously show that hemoglobin and hemin are in a high-spin ferric state in solution, and that the 2p spin-orbit coupling decreases for hemin compared to the hemoglobin, while this is not the case in solids. The spectra were simulated using ligand field multiplet theory, in good agreement with the experiment, allowing quantification of the amount of charge transfer between the porphyrin and Fe3+ ion in hemoglobin and in hemin.

  • 82. Banerjee, Mitali
    et al.
    Banerjee, Rudra
    Majumdar, A. K.
    Mookerjee, Abhijit
    Sanyal, Biplab
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Materialteori.
    Nigam, A. K.
    Magnetism in NiFeMo disordered alloys: Experiment and theory2010Inngår i: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 405, nr 20, s. 4287-4293Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this communication we carry out experimental investigation of the behavior of magnetization with temperature and magnetic field of six samples at different compositions of the disordered ternary alloy NiFeMo. We analyze the data using a fist-principles density functional based electronic structure method and a mean-field phase diagram study.

  • 83.
    Bao, Z
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Yt- och gränsskiktsvetenskap.
    Fink, R. F
    Travnikova, O
    Céolin, D
    Hjelte, I
    Kivimäki, A
    Piancastelli, M. N
    The PCI Effect in the O2 Near ThresholdMolecular Normal Auger SpectraManuskript (Annet vitenskapelig)
  • 84.
    Bao, Z
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Yt- och gränsskiktsvetenskap.
    Travnikova, O
    Céolin, D
    Piancastelli, M. N
    Shape Resonance Affected Molecular Auger Post Collision Interaction (MAPCI) Effect of NO N K-edge Near Threshold Normal Auger SpectraManuskript (Annet vitenskapelig)
  • 85.
    Bao, Zhuo
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Yt- och gränsskiktsvetenskap.
    Synchrotron Radiation Studies of Free and Adsorbed Molecules2008Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This thesis contains two parts. The first part concerns the research work on free molecules using synchrotron-radiation-related techniques. Auger electron spectra of two free open-shell molecules, O2 and NO, were studied experimentally and theoretically. Photoionization experimental technique with tunable synchrotron radiation source was used to induce core-level electron ionization and obtain the KVV normal Auger electron spectra. A quantitative assignment of O2 normal Auger spectrum was obtained by applying ab initio CI calculations and LVI Auger line shape simulations including the bond length dependence of Auger transition rates. The photon energy dependence of normal Auger electron spectra was focused on with photon energies in the vicinities of core-ionization threshold energies. Consequently, the MAPCI (Molecular Auger Post Collision Interaction) theory was developed. Taking the near-threshold O2 normal Auger spectrum as an example, the two extreme cases of MAPCI effect, “atomic-like PCI” and “molecular PCI”, were discovered and discussed. The effect of shape resonance on near-threshold molecular normal Auger spectrum was discussed taking NO near threshold normal Auger spectra as example.

    The second part deals with research work on the chemisorption of small epoxy organic molecules, ethylene oxide, methyl oxirane, on Si (100) surfaces. Synchrotron radiation related techniques, UPS, XPS and NEXAFS, were applied. Based on the valence photoemission spectra, C 1s and Si 2p XPS spectra, the epoxy ring opening reactions of these molecules in chemisorption process were proved. Further tentative search for the surface-adsorbate CDAD effect was performed, and no evident circular dichroism was confirmed.

    Delarbeid
    1. Detailed Theoretical and Experimental Description of Normal Auger Decay in O2
    Åpne denne publikasjonen i ny fane eller vindu >>Detailed Theoretical and Experimental Description of Normal Auger Decay in O2
    Vise andre…
    2008 (engelsk)Inngår i: Journal of Physics B: Atomic, Molecular and Optical Physics, ISSN 0953-4075, E-ISSN 1361-6455, Vol. 41, nr 12, s. 125101-Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    The normal Auger electron spectrum of the O-2 molecule is assigned in detail on the basis of ab initio valence configuration interaction (CI) wavefunctions. Potential energy curves of the ground state, the core-ionized states and the doubly charged final states are calculated and Auger decay rates are obtained with the one-centre approximation. Using the lifetime vibrational interference method, band shapes are obtained for all contributions to the Auger spectrum. The calculated Auger electron spectrum allows us to identify all features observed experimentally. Significant differences to previous assignments are reported. A quantitative simulation of the spectrum is given on the basis of a curve-fitting procedure, in which the energetic positions and intensities of the theoretical bands were optimized. Besides providing a basis for a refined analysis of the spectrum, the fit allows us to assess the accuracy of the calculation. As expected for this level of theory, the absolute accuracy of the valence CI energies is found to be about 0.3 eV. The inherent error of the one-centre transition rates is less than 5% of the most intense transition in the spectrum. The frequently questioned one-centre Auger transition rates are shown to be rather appropriate if applied with reasonable wavefunctions and if the vibrational band structure of the molecular spectrum is properly taken into account.

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-96986 (URN)10.1088/0953-4075/41/12/125101 (DOI)000257177700004 ()
    Tilgjengelig fra: 2008-04-03 Laget: 2008-04-03 Sist oppdatert: 2017-12-14bibliografisk kontrollert
    2. The PCI Effect in the O2 Near ThresholdMolecular Normal Auger Spectra
    Åpne denne publikasjonen i ny fane eller vindu >>The PCI Effect in the O2 Near ThresholdMolecular Normal Auger Spectra
    Vise andre…
    Manuskript (Annet vitenskapelig)
    Identifikatorer
    urn:nbn:se:uu:diva-96987 (URN)
    Tilgjengelig fra: 2008-04-03 Laget: 2008-04-03 Sist oppdatert: 2010-01-13bibliografisk kontrollert
    3. Shape Resonance Affected Molecular Auger Post Collision Interaction (MAPCI) Effect of NO N K-edge Near Threshold Normal Auger Spectra
    Åpne denne publikasjonen i ny fane eller vindu >>Shape Resonance Affected Molecular Auger Post Collision Interaction (MAPCI) Effect of NO N K-edge Near Threshold Normal Auger Spectra
    Manuskript (Annet vitenskapelig)
    Identifikatorer
    urn:nbn:se:uu:diva-96988 (URN)
    Tilgjengelig fra: 2008-04-03 Laget: 2008-04-03 Sist oppdatert: 2010-01-13bibliografisk kontrollert
    4. Electronic Structure of Core-excited and Core-ionized Methyl Oxirane
    Åpne denne publikasjonen i ny fane eller vindu >>Electronic Structure of Core-excited and Core-ionized Methyl Oxirane
    Vise andre…
    2007 (engelsk)Inngår i: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 156, s. 259-264Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    We report a detailed analysis of the electronic structure of methyl oxirane, including core-level photoelectron spectroscopy, X-ray absorption at both C and O K-shells, resonant Auger and normal Auger spectroscopy. The X-ray absorption spectra (XAS) around the C K-edge can be easily interpreted on the ground of the chemical shift between the carbon atoms with different chemical environments. The X-ray absorption data around the O K-edge are quite structureless, hinting for a likely fragmentation process (possibly implying a ring-opening reaction).

    In resonant Auger spectra obtained after excitation below both the C 1s and O 1s ionization thresholds we notice a predominance of spectator decay implying a strong mixing between empty molecular orbitals and Rydberg states.

    Emneord
    Auger decay, X-ray, Fragmentation, Chiral
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-96989 (URN)10.1016/j.elspec.2006.12.068 (DOI)000246726300305 ()
    Tilgjengelig fra: 2008-04-03 Laget: 2008-04-03 Sist oppdatert: 2017-12-14bibliografisk kontrollert
    5. Electronic and Geometric Structure of Methyl Oxirane Adsorbed on Si (100) 2 × 1
    Åpne denne publikasjonen i ny fane eller vindu >>Electronic and Geometric Structure of Methyl Oxirane Adsorbed on Si (100) 2 × 1
    Vise andre…
    2007 (engelsk)Inngår i: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 254, nr 1, s. 108-112Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Electronic and geometric properties of the adsorbate–substrate complex formed upon adsorption of methyl oxirane on Si(1 0 0)2 × 1 at room temperature is reported, obtained with synchrotron radiation-induced valence and core-level photoemission. A ring-opening reaction is demonstrated to occur, followed by a five-membered ring formation involving two of the Si surface atoms bound to a surface dimer. Core-level photoemission spectra support the ring-opening reaction and the SiO and SiC bond formation, while from the valence spectra a more extended molecular fragmentation can be ruled out. We discuss the most likely geometry of the five-membered ring.

    Emneord
    Adsorption, Electronic structure, Geometrical structure, Semiconductors
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-96990 (URN)10.1016/j.apsusc.2007.07.070 (DOI)000250800100025 ()
    Tilgjengelig fra: 2008-04-03 Laget: 2008-04-03 Sist oppdatert: 2017-12-14
    6. The Bonding of Chemisorbed Ethylene Oxide on Si (100) Surface
    Åpne denne publikasjonen i ny fane eller vindu >>The Bonding of Chemisorbed Ethylene Oxide on Si (100) Surface
    Manuskript (Annet vitenskapelig)
    Identifikatorer
    urn:nbn:se:uu:diva-96991 (URN)
    Tilgjengelig fra: 2008-04-03 Laget: 2008-04-03 Sist oppdatert: 2011-12-02
    7. Search for Circular Dichroism Effects in Methyl Oxirane Adsorbed on Si (100)
    Åpne denne publikasjonen i ny fane eller vindu >>Search for Circular Dichroism Effects in Methyl Oxirane Adsorbed on Si (100)
    Vise andre…
    (engelsk)Artikkel i tidsskrift (Fagfellevurdert) Submitted
    Identifikatorer
    urn:nbn:se:uu:diva-96992 (URN)
    Tilgjengelig fra: 2008-04-03 Laget: 2008-04-03 Sist oppdatert: 2011-02-17bibliografisk kontrollert
  • 86.
    Bao, Zhuo
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Yt- och gränsskiktsvetenskap.
    Fink, Reinhold F.
    Travnikova, Oksana
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Yt- och gränsskiktsvetenskap.
    Céolin, Denis
    Svensson, Svante
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Yt- och gränsskiktsvetenskap.
    Piancastelli, Maria Novella
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Yt- och gränsskiktsvetenskap.
    Detailed Theoretical and Experimental Description of Normal Auger Decay in O22008Inngår i: Journal of Physics B: Atomic, Molecular and Optical Physics, ISSN 0953-4075, E-ISSN 1361-6455, Vol. 41, nr 12, s. 125101-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The normal Auger electron spectrum of the O-2 molecule is assigned in detail on the basis of ab initio valence configuration interaction (CI) wavefunctions. Potential energy curves of the ground state, the core-ionized states and the doubly charged final states are calculated and Auger decay rates are obtained with the one-centre approximation. Using the lifetime vibrational interference method, band shapes are obtained for all contributions to the Auger spectrum. The calculated Auger electron spectrum allows us to identify all features observed experimentally. Significant differences to previous assignments are reported. A quantitative simulation of the spectrum is given on the basis of a curve-fitting procedure, in which the energetic positions and intensities of the theoretical bands were optimized. Besides providing a basis for a refined analysis of the spectrum, the fit allows us to assess the accuracy of the calculation. As expected for this level of theory, the absolute accuracy of the valence CI energies is found to be about 0.3 eV. The inherent error of the one-centre transition rates is less than 5% of the most intense transition in the spectrum. The frequently questioned one-centre Auger transition rates are shown to be rather appropriate if applied with reasonable wavefunctions and if the vibrational band structure of the molecular spectrum is properly taken into account.

  • 87. Barth, S.
    et al.
    Joshi, S.
    Marburger, S.
    Ulrich, V.
    Lindblad, A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Öhrwall, G.
    Björneholm, O.
    Hergenhahn, U.
    Observation of resonant interatomic coulombic decay in Ne clusters2005Inngår i: The Journal of Chemical Physics, ISSN 0021-9606, Vol. 122, nr 24, s. 241102-Artikkel i tidsskrift (Fagfellevurdert)
  • 88. Belonoshko, B
    et al.
    Derlet, M
    Mikhaylushkin, S
    Simak, I
    Hellman, O
    Burakovsky, L
    Swift, C
    Johansson, B
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Quenching of bcc-Fe from high to room temperature at high-pressure conditions: a molecular dynamics simulation2009Inngår i: New Journal of Physics, ISSN 1367-2630, E-ISSN 1367-2630, Vol. 11, s. 093039-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The new high-temperature (T), high-pressure (P), body-centered cubic (bcc) phase of iron has probably already been synthesized in recent diamond anvil cell (DAC) experiments (Mikhaylushkin et al 2007 Phys. Rev. Lett. 99 165505). These DAC experiments on iron revealed that the high-PT phase on quenching transforms into a mixture of close-packed phases. Our molecular dynamics simulation and structural analysis allow us to provide a probable interpretation of the experiments. We show that quenching of the high-PT bcc phase simulated with the embedded-atom model also leads to the formation of the mixture of close-packed phases. Therefore, the assumption of the stability of the high-PT bcc iron phase is consistent with experimental observation.

  • 89. Benyahia, K
    et al.
    Nabi, Z
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Khalfi, A
    Magneto-optical Kerr effect (MOKE) of the rare-earth silicide ErSi2 using ab-initio calculations2009Inngår i: Current applied physics, ISSN 1567-1739, E-ISSN 1878-1675, Vol. 9, nr 5, s. 925-927Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present a computational method for the ab-initio study of the magneto-optical quantities using the augmented plane wave plus local orbitals (APW+lo) method. The calculations are performed within the local-density (LDA) approximation. In the present paper, the optical conductivity is the basic quantity for the evaluation of the magneto-optical Kerr effect (MOKE). Thus it is well described and calculated. Considerable work has been performed on the magneto-optical Kerr effect using experiments, however, no experimental or theoretical work has been investigated on rare-earth silicide ErSi2, in particular using ab-initio method. Our results consist a prediction. (C) 2008 Elsevier B.V. All rights reserved.

  • 90. Berge, Maria
    et al.
    Danielsson, Anna
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Fysikundervisningens didaktik. Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Historisk-filosofiska fakulteten, Centrum för genusvetenskap.
    The storylines of learning physics in groups: perspectives on becoming a physicist2008Inngår i: Paper presented at Higher Education Close-up 4 Conference, Cape Town, South Africa, June., 2008Konferansepaper (Fagfellevurdert)
  • 91.
    Bergersen, H.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Abu-samha, M.
    Harnes, J.
    Björneholm, O.
    Svensson, S.
    Sæthre, L. J.
    Børve, K. J.
    Size of neutral argon clusters from core-level photoelectron spectroscopy2006Inngår i: Phys. Chem. Chem. Phys, Vol. 8, s. 1891-Artikkel i tidsskrift (Fagfellevurdert)
  • 92.
    Bergersen, H.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Harnes, J.
    Abu-samha, M.
    Winkler, M.
    Lindblad, A.
    Sæthre, L. J.
    Børve, K. J.
    Björneholm, O.
    Surface tension as driving force for radial structure in mixed molecular clustersManuskript (Annet vitenskapelig)
  • 93.
    Bergersen, H.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Ottosson, N.
    Børve, K. J.
    Sæthre, L. J.
    Björneholm, O.
    Faubel, M
    Öhrwall, G.
    Winter, B.
    Photoelectron spectroscopy of aqueous glycine at different pHManuskript (Annet vitenskapelig)
  • 94.
    Bergersen, Henrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Free Neutral Clusters and Liquids Studied by Electron Spectroscopy and Lineshape Modeling2008Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The electronic and geometrical structure of free neutral clusters and liquids have been studied using synchrotron-radiation based photoelectron and Auger electron spectroscopy in combination with lineshape modeling. A novel experimental setup has been developed for studies of liquids, based on the liquid microjet technique. Theoretical lineshapes have been computed using both classical (molecular dynamics) and quantum mechanical (mainly density functional theory) methods.

    Clusters are finite ensembles of atoms or molecules, ranging in size from a few to several thousand atoms. Apart from being fundamentally interesting, clusters are also promising as building blocks for nano-technology. In this thesis results are presented for rare-gas and molecular clusters, ranging from weakly van-deer-Waals bonded to hydrogen bonded. It is shown that the combination of core-level photoelectron spectroscopy (XPS) and lineshape modeling can be used to estimate the sizes of clusters. A model for treating the effect of inter-molecular nuclear relaxation upon ionization is proposed. The structure of single-component molecular clusters are investigated by molecular dynamics simulations, validated against XPS data. Finally, the radial structure of a two-component molecular cluster is investigated by XPS.

    Liquids have been studied for centuries, but still many questions remain regarding the microscopic properties. With the recent development of the liquid microjet technique, new insight into the atomic structure can be obtained. In this thesis we study aqueous solutions using photoelectron and Auger electron spectroscopy (AES). We investigate the structure of surface active molecules by XPS, study the Auger decay after core-level ionization in aqueous potassium chloride (KCl), and follow the changes in molecular structure of glycine as a function of pH.

    Delarbeid
    1. Size of neutral argon clusters from core-level photoelectron spectroscopy
    Åpne denne publikasjonen i ny fane eller vindu >>Size of neutral argon clusters from core-level photoelectron spectroscopy
    Vise andre…
    2006 Inngår i: Phys. Chem. Chem. Phys, Vol. 8, s. 1891-Artikkel i tidsskrift (Fagfellevurdert) Published
    Identifikatorer
    urn:nbn:se:uu:diva-97060 (URN)
    Tilgjengelig fra: 2008-04-18 Laget: 2008-04-18bibliografisk kontrollert
    2. First observation of vibrations in core-level photoelectron spectra of free neutral molecular clusters
    Åpne denne publikasjonen i ny fane eller vindu >>First observation of vibrations in core-level photoelectron spectra of free neutral molecular clusters
    Vise andre…
    2006 (engelsk)Inngår i: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 429, nr 1-3, s. 109-113Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Core-level photoelectron spectra of free neutral methane clusters have been recorded. These spectra exhibit well-resolved surface and bulk features as well as vibrational fine structure. The vibrational structure in the cluster signal is well reproduced by a theoretical model that assumes independent contributions from inter- and intramolecular modes. The intramolecular contribution to the vibrational line-shape is taken to be equal to that of the monomer in the gas phase, while the intermolecular part is simplified to line broadening. An estimate of the cluster size has been made on the basis of the observed surface-to-bulk intensity ratio.

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-97061 (URN)10.1016/j.cplett.2006.08.034 (DOI)000241018800020 ()
    Tilgjengelig fra: 2008-04-18 Laget: 2008-04-18 Sist oppdatert: 2017-12-14bibliografisk kontrollert
    3. Lineshapes in carbon 1s photoelectron spectra of methanol clusters
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    2006 Inngår i: Phys. Chem. Chem. Phys, Vol. 8, s. 2473-Artikkel i tidsskrift (Fagfellevurdert) Published
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    urn:nbn:se:uu:diva-97062 (URN)