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  • 1.
    Almlöf, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    Hydrogen bond studies. 71. Ab initio calculation of the vibrational structure and equilibrium geometry in HF2 and DF21972In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 17, no 1, p. 49-52Article in journal (Refereed)
    Abstract [en]

    MO LCAO SCF calculations have been performed to investigate the molecular astructure and vibrational spectrum of the bifluoride ion in its normal and deuterated form. The potential energy for nuclear motions has been evaluated as a function of the molecular degrees of freedom, taking only linear geometries into account. The vibrational Schrödinger equation has been solved by expanding the vibrational part of the total wavefunction as a sum of products of linear harmonic-oscillator eigenfunctions. The calculated properties are in good agreement with experiments, and even the minute effects of deuteration are well reproduced.

  • 2. Aquilante, Francesco
    et al.
    Jensen, K. P.
    Roos, Björn O.
    The allyl radical revisited: a theoretical study of the electronic spectrum.2003In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 380, no 5-6, p. 689-698Article in journal (Refereed)
    Abstract [en]

    In this Letter, we report the electronic spectrum of the allyl radical, obtained with multiconfigurational perturbation theory (MS-CASPT2). The assignment of the spectrum is in accordance with experiment to within 0.2 eV. We have computed the complete first Rydberg series and the beginning of the second Rydberg series. A new valence-excited B-2(1) state has been found which has hitherto been hidden by Rydberg transitions. A rationalisation of the electronic spectrum is provided in terms of resonance forms in ground and excited states. This model shows that while a multiconfigurational wavefunction is necessary to qualitatively model the system, the large ionic character of the valence electronic states makes an accurate treatment of the dynamical correlation necessary for a quantitative description of the spectrum.

  • 3. Aquilante, Francesco
    et al.
    Pedersen, Thomas Bondo
    Quartic scaling evaluation of canonical scaled opposite spin second-order Moller-Plesset correlation energy using Cholesky decompositions.2007In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 449, no 4-6, p. 354-357Article in journal (Refereed)
    Abstract [en]

    The scaled opposite spin second-order Moller-Plesset (SOS-MP2) energy expression is reformulated using Cholesky decomposition of the amplitude matrix. The resulting algorithm requires an auxiliary basis or Cholesky representation of the two-electron integrals and shows fourth-order scaling with system size. Based on an analysis of operation counts, we estimate that the present approach is computationally advantageous compared to the analogous fourth-order algorithms that employ Laplace transforms.

  • 4. Barnes, Leslie A
    et al.
    Lindh, Roland
    Department of Theoretical Chemistry, Lund University.
    Symmetry breaking in O+4: an application of the Brueckner coupled-cluster method1994In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 223, no 3, p. 207-214Article in journal (Refereed)
    Abstract [en]

    A recent calculation of the antisymmetric stretch frequency for the rectangular structure of quartet O4+ using the QCISD(T) method gave a value of 3710 cin-1. This anomalous frequency is shown to be a consequence of symmetry-breaking effects, which occur even though the QCISD(T) solution derived from a delocalized SCF reference function lies energetically well below the two localized (symmetry-broken) solutions at the equilibrium geometry. The symmetry breaking is almost eliminated at the CCSD level of theory, but the small remaining symmetry-breaking effects are magnified at the CCSD (T) level of theory so that the antisymmetric stretch frequency is still significantly in error. The Brueckner coupled-cluster method, however, leads to a symmetrical solution which is free of symmetry-breaking effects, with an antisymmetric stretch frequency of 1322 cm-1, in good agreement with our earlier calculations using the CASSCF/CASSI method.

  • 5. Behzadi, Hadi
    et al.
    Esrafili, D
    Beheshtian, Javad
    Hadipour, L
    van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    A density functional study of N-15 chemical shielding tensors in quinolines2009In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 476, no 4-6, p. 196-200Article in journal (Refereed)
    Abstract [en]

    DFT calculations were carried out to characterize the N-15 shielding tensors in quinolines. This computational study is intended to shed light on the differences between two groups of quinolines: series A (7-chloro 4-aminoalkyls quinolines) and series B (quinolines, 3-, 5-, 6-, 8-amino quinolines and 4,8-dichloro quinoline). Unlike the quinolines in series B, the series A quinolines show considerable beta-hematin inhibition activity which is essential for quinoline-based drugs. The results show that the substitution position significantly affects the sigma(11) and sigma(22) components of N-15 shielding tensors of quinolines. The N-15 shielding components are noticeably different for the two series and can be related to their ability to interact with hematin. (C) 2009 Published by Elsevier B. V.

  • 6.
    Belghit, R.
    et al.
    Univ BadjiMokhtar, Dept Phys, Lab LESIMS, BP 12, Annaba 23000, Algeria..
    Belkhir, H.
    Univ BadjiMokhtar, Dept Phys, Lab LESIMS, BP 12, Annaba 23000, Algeria..
    Heciri, D.
    Univ BadjiMokhtar, Dept Phys, Lab LESIMS, BP 12, Annaba 23000, Algeria..
    Bououdina, M.
    Univ Bahrain, Coll Sci, Dept Phys, POB 32038, Sakheer, Bahrain..
    Kadri, M. T.
    Univ BadjiMokhtar, Dept Phys, Lab LESIMS, BP 12, Annaba 23000, Algeria..
    Ahuja, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    First principles study of structural, mechanical and electronic properties of the ternary alkali metal oxides KNaO and RbNaO2018In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 706, p. 684-693Article in journal (Refereed)
    Abstract [en]

    The structural, mechanical and electronic properties of the ternary inter-alkali metal oxides KNaO and RbNaO compounds are investigated by using first principle calculations. The structural parameters and atomic positions are in agreement with the experimental values. The bulk, shear and Young moduli, Poisson's ratio, Lame coefficients and Debye temperature have been calculated. The elastic parameters indicate that these compounds have ductile behavior. The calculated band structures indicate that KNaO and RbNaO have an indirect energy band gap. The charge density distributions reveal an anionic character. This theoretical study is likely to stimulate future experimental researches.

  • 7.
    Bergersen, Henrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics V.
    Abu-samha, M.
    Lindblad, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics V.
    Marinho, Ricardo
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics V.
    Céolin, Denis
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics.
    Öhrwall, Gunnar
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics V.
    Sæthre, L. J.
    Tchaplyguine, M.
    Børve, K. J.
    Svensson, Svante
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics V.
    Björneholm, Olle
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics.
    First observation of vibrations in core-level photoelectron spectra of free neutral molecular clusters2006In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 429, no 1-3, p. 109-113Article in journal (Refereed)
    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.

  • 8. Bernhardsson, Anders
    et al.
    Lindh, Roland
    Department of Theoretical Chemistry, Lund University.
    Karlström, Gunnar
    Roos, Björn O
    Direct self-consistent reaction field with Pauli repulsion: Solvation effects on methylene peroxide1996In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 251, no 3-4, p. 141-149Article in journal (Refereed)
    Abstract [en]

    The properties of methylene peroxide in the gas phase and water have been examined. The solution effects have been modeled with a cavity. To make it possible to optimize the geometry of the cavity, we have added an approximate description of the Pauli repulsion between the solvent and the solute. An efficient direct implementation of the calculation of multicenter multipole operators is also described. We have applied the method to calculate the electric properties of methylene peroxide, a system that is characterized by its near degeneracy between a biradical and a zwitterionic state. As expected, it is shown that solvent effects will stabilize the ionic configuration, resulting in a considerably weakened OO bond and an increased double bond character in the CO bond. The theoretical study has been performed using the multiconfigurational (CAS) SCF method and second-order perturbation theory (CASPT2).

  • 9.
    Borg, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Quantum Chemistry.
    A singlet mechanism for photodissociation of bromofluorobenzenes2007In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 436, no 1-3, p. 57-62Article in journal (Refereed)
    Abstract [en]

    The C-Br photo-fragmentation of bromo-3,5-difluorobenzene (Br-3,5-diFBz) has been investigated using ab initio methods. A reaction coordinate combining a carbon-bromine bond stretch and a bromine out-of-plane bending on the S1 surface has been found with an activation energy of 2.96 kcal/mol, compatible with the observed picosecond time scale.

  • 10.
    Borg, O. Anders
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Quantum Chemistry.
    Karlsson, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science.
    Isomäki-Krondahl, Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Quantum Chemistry.
    Davidsson, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science.
    Lunell, Sten
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Quantum Chemistry.
    Predissociation of Chlorobenzene, beyond the pseudo-diatomic model2008In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 456, no 4-6, p. 123-126Article in journal (Refereed)
    Abstract [en]

    Dissociation of chlorobenzene via the lowest singlet excited state has been investigated by means of pump-probe femtosecond spectroscopy and spin-orbit corrected ab initio quantum chemistry. We have found that the so far accepted model with a (1)pi pi* -> (3)pi/n sigma* reaction mechanism has to be amended. We suggest that the mechanism goes via a transition from (1)pi pi* to a pi sigma* state that is to 90% a singlet. Further, three nuclear degrees of freedom required to describe the dissociation have been defined.

  • 11.
    Brumboiu, Iulia E.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Anselmo, A. S.
    Brena, Barbara
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Dzwilewski, A.
    Svensson, K.
    Moons, E.
    Near-edge X-ray absorption fine structure study of the C-60-derivative PCBM2013In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 568, p. 130-134Article in journal (Refereed)
    Abstract [en]

    The fullerene derivative [6,6]-phenyl-C-61-butyric acid methyl ester plays a key role for electron transport in polymer solar cells. We have studied the unoccupied molecular orbitals of PCBM by near edge X-ray absorption fine structure spectroscopy and were able to assign the main resonances to molecular moieties by comparison with calculated sum spectra of individual carbons. We analyzed specifically the origin of the high-energy shoulder to the first pi*-resonance and identified contributions from the lowest-energy transition of a specific carbon in the phenyl and from transitions to higher unoccupied orbitals of the unmodified carbons in the C-60-cage. 

  • 12.
    Brändas, Erkki
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    Mårtensson, Olle
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    Wave function constructed from complex hybrids1969In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 3, no 5, p. 315-318Article in journal (Refereed)
    Abstract [en]

    The influence on the total wave function of an atomic basis consisting of complex hybrids is considered. The complex character of the wave function in the MO-LCAO scheme ss well as in the VB method is derived, and its consequences with respect to time reversal symmetry are discussed.

  • 13. Buendia, E.
    et al.
    Galvez, F. J.
    Maldonado, Pablo
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Sarsa, A.
    Dynamical correlation effects in the transition probability: A study for the atoms Li to Ar2012In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 548, p. 1-6Article in journal (Refereed)
    Abstract [en]

    Explicitly correlated wave functions constructed as a Jastrow correlation factor times a model function have been obtained for the ground and the first excited state of opposite parity of the atoms Li to Ar. Single and restricted multi-configuration model functions are employed. Line strength, oscillator strength and transition probabilities have been obtained. An analysis of the different correlation mechanisms considered, single particle excitations and dynamical correlations, on these quantities is carried out. All calculations have been done by using Variational Monte Carlo, except when no Jastrow is involved where calculations have been performed using the Optimized Effective Potential method. (C) 2012 Elsevier B. V. All rights reserved.

  • 14. Buendia, E.
    et al.
    Galvez, F. J.
    Maldonado, Pablo
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Sarsa, A.
    Explicitly correlated wave functions for atoms and singly charged ions from Li through Sr: Variational and Diffusion Monte Carlo results2014In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 615, p. 21-25Article in journal (Refereed)
    Abstract [en]

    Total energies calculated from explicitly correlated wave functions for the ground state of the atoms Li to Sr and their singly charged anions and cations are obtained. Accurate all electron, non-relativistic Variational and Diffusion Monte Carlo energies are reported. The quality of the results, when comparing with exact estimations and experimental electron affinities and ionization potential is similar for all of the atoms studied. The parameterization of the explicitly correlated wave functions for all of the atomic systems studied is provided.

  • 15. Buendia, E.
    et al.
    Galvez, F. J.
    Maldonado, Pablo
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Sarsa, A.
    Quantum Monte Carlo ionization potential and electron affinity for transition metal atoms2013In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 559, p. 12-17Article in journal (Refereed)
    Abstract [en]

    Non-relativistic all-electron Quantum Monte Carlo ground state energies of the neutral atoms K to Zn and positive and negative ions are calculated starting from explicitly correlated wave functions. The accuracy obtained for these atoms and ions in the fourth period is similar to that reached for those in the second and third periods. For the atoms and ions for which the 4s-4p near degeneracy effect can be important a restricted multi-configuration expansion has been employed. Ionization potentials and electron affinities have been calculated showing a good agreement with the experimental values.

  • 16. Chatterjee, Sanjukta
    et al.
    Wang, J W
    Kuo, W S
    Tai, N H
    Salzmann, C
    Li, W L
    Hollertz, R
    Nüesch, F A
    Chu, B T T
    Mechanical reinforcement and thermal conductivity in expanded graphene nanoplatelets reinforced epoxy composites2012In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 531, p. 6-10Article in journal (Refereed)
    Abstract [en]

    Influence of reinforcements on mechanical and thermal properties of graphene nanoplatelets/epoxy com-posites is investigated. Amine functionalized expanded graphene nanoplatelets (EGNPs) were dispersed within epoxy resins using high-pressure processor followed by three roll milling. Functionality on the EGNPs was confirmed with FTIR and micro-Raman spectroscopy. Bending and nano-mechanical testingwas performed on the composites. Incorporation of EGNPs improved the flexural modulus and hardness of the composite and increased fracture toughness by up to 60%. Marked improvement was observed inthermal conductivity of the composites reaching 36% at 2 wt.% loading. Functionalized EGNPs exhibited significant improvements indicating favorable interaction at EGNPs/polymer interface.

  • 17. Dopieralski, Przemyslaw D.
    et al.
    Burakowski, Andrzej
    Latajka, Zdzislaw
    Olovsson, Ivar
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Hydration of NaHCO3, KHCO3, (HCO3-)(2), HCO3- and CO32- from molecular dynamics simulation and speed of sound measurements2011In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 507, no 1-3, p. 89-95Article in journal (Refereed)
    Abstract [en]

    Car-Parrinello molecular dynamics and acoustic method have been applied to determine the hydration of HCO3- and CO32- ions in aqueous solution. From CPMD simulations the hydration numbers are 5.3 and 8.5 for the HCO3- and CO32- ions, respectively. From speed of sound and density measurements the hydration numbers for HCO3- and CO32- are 5.5 and 10.2, respectively. Our attempt to answer the old question concerning the status of HCO3 in solution quite well support the earlier spectroscopic results that no (HCO3)(2) is present in the solution but the existence of the minor amount of dimers cannot be definitely excluded.

  • 18. Dopieralski, Przemyslaw
    et al.
    Latajka, Zdzislaw
    Olovsson, Ivar
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Proton distribution in KHCO3 from ab initio molecular dynamics simulation2009In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 476, no 4-6, p. 223-226Article in journal (Refereed)
    Abstract [en]

    The proton distribution in the (HCO3)22- dimer of KHCO3 at 298 K has been studied with the Car-Parrinello molecular dynamics (CPMD) and path integrals molecular dynamics (PIMD) simulations. According to earlier neutron studies hydrogen is disordered and occupies two positions with an occupancy ratio of 0.804/0.196. CPMD results with four cells reproduce experimental data with high accuracy. The occupancy ratio from the CPMD simulation after 35 ps run is 0.783/0.217. Present results support a mechanism for the disorder which involves proton transfer from donor to acceptor and not orientational disordering of the entire dimer. The question of simultaneous or successive proton transfer in the two hydrogen bonds in the dimer is ambiguous. In present CPMD simulations the observed time lag between proton transfers within one dimer was in the range of 1-20 fs.

  • 19. Du, Wencheng
    et al.
    Zhao, Chuanzong
    Liu, Kunpeng
    Li, Hu
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Chen, Yougen
    Bai, Wenyan
    Ahuja, Rajeev
    Qian, Zhao
    Defective and Doped Aluminum Nitride Monolayers for NO Adsorption: Physical Insight2020In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448Article in journal (Refereed)
  • 20. Ehara, M.
    et al.
    Tamaki, R.
    Nakatsuji, H.
    Lucchese, R. R.
    Söderström, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Tanaka, T.
    Hoshino, M.
    Kitajima, M.
    Tanaka, H.
    Fanis, A. De
    Ueda, K.
    Vibrationally resolved nitrogen K-shell photoelectron spectra of the dinitrogen oxide molecule: Experiment and theory2007In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 438, no 1–3, p. 14-19Article in journal (Refereed)
  • 21. Ehara, Masahiro
    et al.
    Tamaki, Ryota
    Nakatsuji, Hiroshi
    Lucchese, Robert
    Söderström, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics.
    Tanaka, Takahiro
    Hoshino, Masaki
    Kitajima, Masashi
    Tanaka, Hiroshi
    De Fanis, Alberto
    Ueda, Kiyoshi
    Vibrationally resolved nitrogen K-shell photoelectron spectra of the dinitrogen oxide molecule: Experiment and theory2007In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 438, no 1-3, p. 14-19Article in journal (Refereed)
    Abstract [en]

    Vibrationally resolved Nc and Nt K-shell photoelectron spectra of the dinitrogen oxide have been studied experimentally and theoretically. Vibrational frequencies for the Nc and Nt 1s ionized states obtained from the 2D potential surfaces computed by the CCSD(T) method within the equivalent core approximation reasonably agree with the experimental values. Experimental relative intensities of the vibrational structure are reasonably reproduced by the multi-channel Schwinger configuration interaction method (MCSCI) with the computed 2D potential surfaces. Improved relaxed geometries of these core–hole states are obtained from fitting the experimental spectra using the MCSCI calculations and regarding the bond lengths as fitting parameters.

  • 22.
    Eland, J. H. D.
    et al.
    Univ Oxford, Phys & Theoret Chem Lab, Dept Chem, Oxford OX1 3QZ, England.;Univ Gothenburg, Dept Phys, SE-41296 Gothenburg, Sweden..
    Plogmaker, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Lablanquie, P.
    Univ Paris 06, LCPMR, F-75231 Paris 05, France..
    Penent, F.
    Univ Paris 06, LCPMR, F-75231 Paris 05, France..
    Palaudoux, J.
    Univ Paris 06, LCPMR, F-75231 Paris 05, France..
    Nicolas, C.
    LOrme des Merisiers, Synchrotron SOLEIL, FR-91192 Gif Sur Yvette, France..
    Robert, E.
    LOrme des Merisiers, Synchrotron SOLEIL, FR-91192 Gif Sur Yvette, France..
    Miron, C.
    LOrme des Merisiers, Synchrotron SOLEIL, FR-91192 Gif Sur Yvette, France.;Horia Hulubei Natl Inst Phys & Nucl Engn, ELI NP, RO-077125 Magurele, Jud Ilfov, Romania..
    Feifel, Raimund
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics. Univ Gothenburg, Dept Phys, SE-41296 Gothenburg, Sweden..
    Wide range double photoionisation spectra of N-2 and CO22016In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 646, p. 31-35Article in journal (Other academic)
    Abstract [en]

    Using a magnetic bottle time-of-flight electron spectrometer we have measured double photoionisation spectra of N-2 and CO2 covering the range from threshold up to the triple ionisation energies. The experiments demonstrate the use of a new asynchronous chopper in eight-bunch mode of the synchrotron radiation source SOLEIL. For CO22+ some broad bands in the Auger spectra are found to have multiple resolved counterparts in the photoionisation spectrum. All the bands in the Auger spectra have counterparts in the photoionisation spectra, where extra bands attributed to triplet states are present. In the spectrum of N-2(2+) we suggest reassignment of one band.

  • 23. Eland, J.H.D
    et al.
    Linusson, Per
    Hedin, Lage
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science, Soft X-Ray Physics.
    Andersson, Egil
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science, Soft X-Ray Physics.
    Rubensson, Jan-Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science, Soft X-Ray Physics.
    Feifel, Raimund
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science, Soft X-Ray Physics.
    Triple ionisation of methane by double Auger and related pathways2010In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 485, no 1-3, p. 21-25Article in journal (Refereed)
    Abstract [en]

    Triple ionisation of methane by decay of the singly charged ion with a 1s vacancy produces a trication spectrum starting near 70 eV binding energy. Vibrational excitation in the initial hole state broadens and shifts the triple ionisation bands. Ionisation through core-valence doubly ionised states gives lower triple ionisation onsets and changes the spectral intensity pattern in accordance with retention of the initial valence holes in course of the double Auger effect. The double Auger effects occur both directly and as cascades, the different pathways producing different electron distributions and final state spectra. (C) 2009 Elsevier B. V. All rights reserved.

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  • 24.
    Eland, John H. D.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Linusson, P.
    Mucke, Melanie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Feifel, Raimund
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Homonuclear site-specific photochemistry by an ion-electron multi-coincidence spectroscopy technique2012In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 548, p. 90-94Article in journal (Refereed)
    Abstract [en]

    By combining multi-particle coincidence detection of electrons and ions with ionisation by soft X-ray synchrotron radiation we demonstrate an effective tool for atomic spectroscopy and site-specific photochemistry. Its most novel capability is application to molecular fragmentation after K-shell vacancy production in atoms distinguished only by their chemical environment.

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    fulltext
  • 25.
    Fisher, M.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    Rämme, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    Claesson, Stig
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    Szwarc, M.
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    Collapse of e(-), Na+ pairs into sodium atoms and the reactions of solvated electrons and of e(-), Na+ pairs1971In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 9, no 4, p. 309-312Article in journal (Refereed)
    Abstract [en]

    Solvated electrons photoejected from pyrenide, pi(radical anion), may combine in THF with Na+ cations, form e(-), Na+ pairs which can collapse into sodium atoms Na-0. The rate constants of these reactions and those of the various transients with pyrene were determined.

  • 26.
    Fisher, M.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    Rämme, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    Claesson, Stig
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    Szwarc, M.
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    Kinetics of electron-transfer B-radical anion + pi -> B + pi(radical anion) and B-radical anion, Na+ + pi -> B + pi(radical anion), Na+ in tetrahydrofuran1971In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 9, no 4, p. 306-308Article in journal (Refereed)
    Abstract [en]

    Photoejection of clcctrons from pyrenide. pi(radical anion), in the presence of excess of biphenyl yields biphenylide, B-radical anion, and the rate constants of the reactions B-radical anion + pi -> B + pi(radical anion) and B-radical anion, Na+ + pi -> pi(radical anion), Na+ + B were determined.

  • 27.
    Gelius, Ulrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    Roos, B.
    Siegbahn, P.
    Ab initio MO SCF calculations of ESCA shifts in sulphur-containing molecules1970In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 4, no 8, p. 471-475Article in journal (Refereed)
    Abstract [en]

    Ab initio MO SCF calculations in a Gaussian basis for a number of molecules have been performed to study the chemical shift of sulphur 2p-electrons. Estimates of chemical shifts and comparison with experimental shifts are reported. Sulphur 3d-orbitals are shown to be important for the magnitude of the shifts.

  • 28.
    Goscinski, Osvaldo
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    Density of states in narrow energy bands1971In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 9, no 4, p. 293-295Article in journal (Refereed)
    Abstract [en]

    The density of states in the one-band short-range interaction model approximated with Hubbard's decoupling is equal to the I-independent band theoretical result at E = T-o and E = T-o + E. Improved decoupling procedures remove this anomaly.

  • 29.
    Goscinski, Osvaldo
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    Brändas, Erkki
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    Dispersion forces, second- and third-order energies1968In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 2, no 5, p. 299-302Article in journal (Refereed)
    Abstract [en]

    The properly symmetrized second order energy, epsilon(Q)(2). has been observed to approach one half of the correct dispersion energy epsilon(2) for large interactomic distances. We contend that the proper quantity to be examined is epsilon(Q)(2)lambda(Q). lambda(Q) approaches epsilon(Q)(2)/(epsilon(Q)(2) - epsilon(Q)(3)) approximate to 2 at R=8a(o) for H-2 and epsilon(Q)(2)/epsilon(Q)(3) approximate to 2. Hence E-o - epsilon(Q)(1) + epsilon(Q)(2) is a bad approximation.

  • 30.
    Goscinski, Osvaldo
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    Lukman, B.
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    Moment-conserving decoupling of Green functions via Pade approximants1970In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 7, no 6, p. 573-576Article in journal (Refereed)
    Abstract [en]

    A generalization of the Pade approximant technique obtained by inner projections leads to approximate Green functions whose spectral densities satisfy a certain number of frequency moments. This approach contains decoupling schemes previously given and their explicit representation in terms of the moments.

  • 31. Gueorguiev, G. K.
    et al.
    Czigany, Zs.
    Furlan, Andrej
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Stafström, S.
    Hultman, L.
    Intercalation of P atoms in Fullerene-like CPx2011In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 501, no 4-6, p. 400-403Article in journal (Refereed)
    Abstract [en]

    The energy cost for P atom intercalation and corresponding structural implications during formation of Fullerene-like Phosphorus carbide (FL-CPx) were evaluated within the framework of Density Functional Theory. Single P atom interstitial defects in FL-CPx are energetically feasible and exhibit energy cost of 0.93-1.21 eV, which is comparable to the energy cost for experimentally confirmed tetragon defects and dangling bonds in CPx. A single P atom intercalation event in FL-CPx can increase the inter-sheet distance from 3.39-3.62 angstrom to 5.81-7.04 angstrom. These theoretical results are corroborated by Selected Area Electron Diffraction characterization of FL-CPx samples.

  • 32.
    Hamrin, Kjell
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    Johansson, Gunilla
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    Fahlman, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    Nordling, Carl
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    Siegbahn, Kai
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    Lindberg, B.
    Structure studies of sulphur compounds by ESCA1968In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 1, no 11, p. 557-559Article in journal (Refereed)
    Abstract [en]

    Results, obtained by means of the ESCA-technique (Electron Spectroscopy for Chemical Analysis), are reported on the correlation between the binding energy of the inner electrons of sulphur and the chemical state and environment, with particular emphasis on the sulphur-oxygen bond. A charge-binding energy correlation is established which can be used for the estimation of charge on sulphur in compounds with uncertain structure or composition.

  • 33.
    Hamrin, Kjell
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    Johansson, Gunilla
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    Gelius, Ulrik
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    Fahlman, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    Nordling, Carl
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    Siegbahn, Kai
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    Ionization energies in methane and ethane measured by means of ESCA1968In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 1, no 13, p. 613-615Article in journal (Refereed)
    Abstract [en]

    Ionization energies for the molecular orbitals in methane and ethane are obtained by means of the ESCA technique. In methane the 2a(1) electrons are found at a binding energy of 23.1 eV: in ethane the 2a(1) level is split up in two levels due to the interaction between the carbon atoms.

  • 34.
    Heciri, D.
    et al.
    Univ Badji Mokhtar, Fac Sci, Dept Phys, Lab Studies Surface & Interfaces Solid Matter LES, Annaba, Algeria.
    Belkhir, H.
    Univ Badji Mokhtar, Fac Sci, Dept Phys, Lab Studies Surface & Interfaces Solid Matter LES, Annaba, Algeria.
    Hamidani, A.
    Univ 8 Mai Guelma, Fac Math Comp & Mat Sci, Phys Lab Guelma, Guelma 24000, Algeria.
    Bououdina, M.
    Univ Bahrain, Coll Sci, Dept Phys, POB 32038, Zallaq, Bahrain.
    Ahuja, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Theoretical investigation of structural, electronic and optical properties of (BeS)(1) /(BeSe)(1), (BeSe)(1)/(BeTe)(1) and (BeS)(1)/(BeTe)(1) superlattices under pressure2018In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 713, p. 71-84Article in journal (Refereed)
    Abstract [en]

    The influence of hydrostatic pressure on structural, electronic and optical properties of short period (BeS)(1)/(BeSe)(1), (BeSe)(1)/(BeTe)(1) and (BeS)(1)/(BeTe)1 superlattices, has been investigated. The lattice parameters a and c for the tetragonal unit cell obtained by total energy calculations are in good agreement with the values calculated by macroscopic elasticity theory. The (BeS)(1)/(BeSe)(1) superlattice possesses an indirect band gap while (BeSe)(1)/(BeTe)(1) and (BeS)(1)/(BeTe)(1) superlattices possess a direct band gap. The pressure ranges from 0 to 47 GPa for (BeS)(1)/(BeSe)(1), 0 to 39 GPa for (BeSe)(1)/(BeTe)(1), and 0 to 45 GPa for (BeS)(1)/(BeTe)(1) , meanwhile the pressure dependence of the energy band gap along different symmetry directions obey the equation E-g(p)= E-g+ ap + bp(2). The pressure coefficient of the indirect band gap for (BeS)(1)/(BeSe)(1) is - 22.5675 x 10(-3) eV(GPa)(-1), while that of the direct band gap is estimated as - 25.8581 x 10(-3)eV(GPa)(-1) and - 24.4695 x 10(-3)eV(GPa)(-1) for (BeSe)(1)/(BeTe)(1) and (BeS)(1)/(BeTe)(1), respectively. The variation of the static dielectric constant with pressure is discussed.

  • 35.
    Hermansson, Kersti
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    A simulated X-ray diffraction study of liquid water: Beyond the spherical-atom approximation1996In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 260, no 1-2, p. 229-235Article in journal (Refereed)
    Abstract [en]

    The total electron density of a water molecule differs significantly from the superposition of the O + H + H spherical-atom densities by way of bonding and lone-pair electron charge accumulations. Such non-spherical electron density features on neighbouring molecules typically lie in the range 2-4 Angstrom apart in liquid water. Their influence on the diffracted coherent X-ray intensity for liquid water has been simulated, based on molecular dynamics data and non-spherical atomic electron deformation functions, for the water molecule. It is found that in the liquid water sample, the deformation densities on different molecules interfere significantly in the scattering process, but the effect is largely eliminated because of statistical cancellations over Q vector directions and time, The result is that the influence from the deformation densities on g(r) is large for intramolecular distances, but small for intermolecular distances.

  • 36.
    Hermansson, Kersti
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    INFLUENCE OF RIGID-BODY MOTION ON THE DEFORMATION ELECTRON-DENSITY OF H2O1983In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 99, no 4, p. 295-300Article in journal (Refereed)
  • 37.
    HERMANSSON, KERSTI
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    O-H BONDS IN ELECTRIC-FIELDS - ELECTRON-DENSITIES AND VIBRATIONAL FREQUENCY-SHIFTS1995In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 233, no 4, p. 376-382Article in journal (Refereed)
    Abstract [en]

    The changes in the electron density distribution caused by varying the O-H bond length for HDO and OH- in uniform electric fields are investigated and related to the frequency shifts for the uncoupled O-H stretching vibration. Numerical integration of difference density maps, Delta rho=rho(r(OH)+Delta r(OH))-rho(r(OH)), reproduces the electronic contribution to theta mu(parallel to)(total)/theta r(OH), if the integration is carried out to a distance of approximate to 3.5 Angstrom from the O atom. The frequency shift Delta nu, is proportional to -E(parallel to) X[d mu(parallel to)(permanent)(r(OH))/dr(OH)]-1/2E(parallel to)[theta mu(parallel to)(induced)(E(parallel to), r(OH))/theta r(OH)] and electron density maps corresponding to the electronic parts of these terms are presented. Experimentally it has been found that the OH- ion shows a frequency upshift when bound in a moderately strong field, while water molecules show a downshift. The electron density maps show why d mu(parallel to)(permanent)(r(OH))/dr(OH) is positive for HDO and negative for OH-, resulting in a downshift for bound water an an upshift for bound OH-. For positive fields, theta mu(parallel to)(induced)/theta r(OH) is positive for both HDO and OH- and gives a downshift contribution.

  • 38.
    Hermansson, Kersti
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Lindgren, Jan
    AN ABINITIO STUDY OF ANHARMONIC POTENTIAL-ENERGY SURFACES FOR BOUND WATER-MOLECULES1988In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 146, no 5, p. 459-464Article in journal (Refereed)
  • 39.
    HERMANSSON, KERSTI
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    LINDGREN, JAN
    PROBST, MICHAEL M
    NONADDITIVITY OF OH FREQUENCY-SHIFTS IN ION WATER-SYSTEMS1995In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 233, no 4, p. 371-375Article in journal (Refereed)
    Abstract [en]

    The intramolecular OH stretching frequency shift observed for water on formation of 'cation-water...H-bond acceptor' complexes is highly non additive. The uncoupled OH frequency shift has been calculated by ab initio methods for q(+)-OH2 and OH2...q(-) complexes of different geometries and for a series of Mg2+.(H2O)(n)...(H2O)(m) complexes, and we argue that the non-additivity (cooperativity) of the frequency shifts is largely a consequence of the parabolic shape of the frequency versus electric field curves.

  • 40.
    Hermansson, Kersti
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Lunell, Sten
    ELECTRON-DENSITY OF H2O IN A CRYSTALLINE ENVIRONMENT1981In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 80, no 1, p. 64-68Article in journal (Refereed)
  • 41. Holt, Asbjorn
    et al.
    Karlström, Gunnar
    Lindh, Roland
    Department of Theoretical Chemistry, Lund University.
    The charge capacity of the chemical bond2007In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 436, no 1-3, p. 297-301Article in journal (Refereed)
    Abstract [en]

    A bond capacitance is introduced via the LoProp formalism, and the calculated bond capacitances reflects the properties of the corresponding chemical bond remarkably well. It is clearly possible to characterize the properties of the chemical bond with the help of the calculated bond capacitances.

  • 42.
    Häggström, Lennart
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    Wäppling, Roger
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    Annersten, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    Mössbauer study of iron-rich biotites1969In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 4, no 3, p. 107-108Article in journal (Refereed)
    Abstract [en]

    It has been possible by detailed studies of the Mossbauer spectra for biotite, to distinguish between the two iron sites.

  • 43. Johansson, E. M. J.
    et al.
    Odelius, M.
    Gorgoi, M.
    Karis, Olof
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science, Surface and Interface Science.
    Ovsyannikov, R.
    Schafers, S.
    Svensson, Svante
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science, Surface and Interface Science.
    Siegbahn, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science, Surface and Interface Science.
    Rensmo, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science, Surface and Interface Science.
    Valence Electronic Structure Of Ruthenium Based Complexes Probed By Photoelectron Spectroscopy At High Kinetic Energy (Hike) And Modeled By Dft Calculations2008In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 464, no 4-6, p. 192-197Article in journal (Refereed)
    Abstract [en]

    The valence electronic structure of a series of molecular films containing ruthenium polypyridine complexes has been investigated by photoelectron spectroscopy (PES) at high kinetic energy (HIKE) using hard X-ray. The experiment shows the possibility to experimentally probe the metal contribution to the valence spectra in a bulk sensitive mode. Specifically to directly follow the Ru 4d contribution to the highest occupied molecular orbitals of such complexes. The experimental spectra are accurately modeled by DFT calculations only if a crystal structure environment is taken into account showing the importance of intermolecular interaction for modeling the electronic structure of such complexes.

  • 44.
    Johansson, Erik M. J.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Physical Chemistry.
    Pradhan, Sulena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry.
    Wang, Ergang
    Unger, Eva L
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Physical Chemistry.
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Physical Chemistry.
    Andersson, Mats R.
    Efficient infiltration of low molecular weight polymer in nanoporous TiO22011In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 502, no 4-6, p. 225-230Article in journal (Refereed)
    Abstract [en]

    The polymer APFO(3) was prepared with different molecular weights to study how the infiltration into nanoporous TiO2 films of different thickness depends on the size of the polymer. Also two different sizes of TiO2 nanoparticles were investigated to understand the effect of different pore size. It was observed that the lowest molecular weight polymer dissolved in chlorobenzene could infiltrate the nanoporous TiO2 network up to several micrometer thick films. It was concluded that efficient polymer infiltration into thick nanoporous layers was possible for the polymers with an estimated average chain length smaller than the diameter of the nanoparticles.

  • 45.
    Johansson, Erik M. J.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Physical Chemistry.
    Schölin, Rebecka
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Siegbahn, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Physical Chemistry.
    Rensmo, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Energy level alignment in TiO(2)/dipole-molecule/P3HT interfaces2011In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 515, no 1-3, p. 146-150Article in journal (Refereed)
    Abstract [en]

    Controlling the energy levels at the interface between an inorganic and an organic material is of importance to improve the properties in devices based on such hybrid interfaces, and can be obtained by the incorporation of dipole molecules between the materials. In this report interfaces containing TiO(2), a dipole molecule (benzoic acid or 4-nitrobenzoic acid) and a polymer, poly(3-hexylthiophene) (P3HT) were investigated using high kinetic energy photoelectron spectroscopy. We could successfully measure through all materials in the fully assembled systems, and thereby experimentally quantify the dipole induced change in the energy level alignment of the polymer and the TiO(2).

  • 46.
    Kersti, Hermansson
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Bopp, Philippe A.
    Department of Chemistry, Université Bordeaux 1, 351, Cours de la Libération Bld. A12, F-33405 Talence CEDEX, France.
    Spångberg, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Pejov, Ljupco
    Institute of Chemistry, Faculty of Science, Sts. Cyril and Methodius University, P.O. Box 162, 1000 Skopje, Republic of Macedonia.
    Mitev, Pavlin D.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    The vibrating hydroxide ion in water2011In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 514, no 1-3, p. 1-15Article in journal (Refereed)
    Abstract [en]

    The OH ion in water is studied using a CPMD/BLYP + QMelectronic + QMvibrational approach. The ion resides in a cage of water molecules, which are H-bonded among each other, and pinned by H-bonding to the ion’s O atom. The water network keeps the ‘on-top’ water in place, despite the fact that this particular ion-water pair interaction is non-binding. The calculated OH vibrational peak maximum is at ∼3645 cm−1 (experiment ∼3625 cm−1) and the shift with respect to the gas-phase is ∼ +90 cm−1 (experiment +70 cm−1). The waters molecules on each side of the ion (O and H) induce a substantial OH vibrational blueshift, but the net effect is much smaller than the sum. A parabolic ‘frequency-field’ relation qualitatively explains this non-additivity. The calculated ‘in-liquid’ ν(OH) anharmonicity is 85 cm−1.

  • 47. Kuhnt, Christian
    et al.
    Karnahl, Michael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Rau, Sven
    Schmitt, Michael
    Dietzek, Benjamin
    Popp, Juergen
    The impact of bromine substitution on the photophysical properties of a homodinuclear Ru-tpphz-Ru complex2011In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 516, no 1-3, p. 45-50Article in journal (Refereed)
    Abstract [en]

    Ruthenium-polypyridine complexes play an important role as photosensitizers in supramolecular photocatalysis. Using multiple Ru-centers within a single supramolecular catalyst might be a promising path for improving its efficiency. The connection of several chromophores may, however, lead to direct interaction amongst individual photoactive centers, which is at the core of the work at hand. The work focuses on the photophysics of [(tbbpy)(2)Ru(3,16-Br(2)-tpphz)Ru(tbbpy)(2)](PF(6))(4) (1, tpphz = tetrapyrido[3,2-a: 2',3'-c: 3 '',2 ''-h:2''',3'''-j] phenazine, tbbpy = 4,4'-di-tert.-butyl-2,2'-bipyridine) and aims at detailing the impact of the bromine substituents on bridging ligand photoinduced intramolecular charge-transfer dynamics. It is shown that the introduction of the bromine reduces the driving force for intra-ligand charge-transfer steps and impacts exciton-exciton annihilation at high pump intensities.

  • 48.
    Kvashnina, Kristina O.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Butorin, Sergei M.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Modin, A.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics II.
    Soroka, Inna
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Marcellini, Moreno
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics.
    Nordgren, Joseph
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics II.
    Guo, J-H
    Werme, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics II.
    In situ X-ray absorption study of copper films in ground water solutions2007In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 447, no 1-3, p. 54-57Article in journal (Refereed)
    Abstract [en]

    This study illustrates how the damage from copper corrosion can be reduced by modifying the chemistry of the copper surface environment. The surface modification of oxidized copper films induced by chemical reaction with Cl− and in aqueous solutions was monitored by in situ X-ray absorption spectroscopy. The results show that corrosion of copper can be significantly reduced by adding even a small amount of sodium bicarbonate. The studied copper films corroded quickly in chloride solutions, whereas the same solution containing 1.1 mM prevented or slowed down the corrosion processes.

  • 49.
    Larsson, S.
    Uppsala University, Disciplinary Domain of Science and Technology, Faculty of Mathematics and Science.
    A method of obtaining Brueckner orbitals for atoms and molecules1970In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 7, no 2, p. 165-170Article in journal (Refereed)
    Abstract [en]

    A method, resembling the Hartree-Fock method, is presented of obtaining Brueckner orbitals through a knowledge of pair correlation functions. The pair correlation functions may be obtained from approximate wavefunctions. They may also be Bethe-Goldstone type pairs, or simpler types of pair function.

  • 50.
    Lewin, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Råsander, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Klintenberg, Mattias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Bergman, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Eriksson, Olle
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Design of the Lattice Parameter of Embedded Nanoparticles2010In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 496, no 1-3, p. 95-99Article in journal (Refereed)
    Abstract [en]

    It is found that the bonding of nanoparticles in nancomposites can be influenced by interactions with a surrounding matrix phase. A model involving charge transfer between phases is presented, and supported by DFT-simulations. The model explains observations in nanocomposite nc-TiCx/a-C of additional interface states and lattice expansion of TiCx. It is suggested that this approach can be extended to other types of nanocomposites, and that it opens for new possibilities in materials design.

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