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  • 1.
    Andersson, Marit
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Olin, Åke
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    A modified standard addition method in X-ray fluorescence spectrometry1993In: Talanta: The International Journal of Pure and Applied Analytical Chemistry, ISSN 0039-9140, E-ISSN 1873-3573, Vol. 40, no 5, p. 669-674Article in journal (Refereed)
    Abstract [en]

    A modified standard addition method for single element determination by X-ray fluorescence spectrometry has been studied. The attenuation properties of the standard added samples are kept constant by adding decreasing amounts of an attenuation modifier along with increasing amounts of a standard. In this way the standard addition curve will be a straight line in cases where the ordinary standard addition curve is non-linear, and linear regression can be used to evaluate the concentration of the analyte. Standard additions of oxides of a number of elements, with and without modifier, have been made to cellulose powder or a mixture of aluminium oxide and polyethylene as matrices in order to test the method. The method has been applied to the determination of zinc in fly-ash from a steel work and of iron in cement. The fly-ash contained about 5% of zinc and the cement samples between 2 and 5% of Fe(2)O(3). The results were compared with those obtained by ICP-AES after decomposition of samples in lithium tetraborate or lithium metaborate and dissolution of the melt in 10%(v/v) nitric acid. The results agreed within 2%, relative, for fly-ash and within 3-6%, relative, for cement samples.

  • 2.
    Andersson, Pher
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Sharpless, K. Barry
    A Dramatic Ligand Effect on the Relative Reactive Reactivites of Substituted Alkenes with Osmium Tetroxide1993In: J. Am. Chem. Soc., no 115, p. 7047-7048Article in journal (Refereed)
  • 3.
    Berger, R
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Oorganisk kemi.
    Önnerud, P
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Oorganisk kemi.
    Laligant, Y
    Le Bail, A
    The structure of Li3Cu2O4, a compound with formal mixed valence1993In: J Alloys Comp, Vol. 190, p. 295-299Article in journal (Refereed)
    Abstract [en]

    The structure of Li3Cu2O4 was solved from X-ray powder diffraction data and refined from a multiphase specimen using the Rietveld method. The cuprate crystallizes in C2/m with Z=2. The compound has a small homogeneity range. Typical parameters are a= 9.946(5) Angstrom, b= 2.778(2) Angstrom, c= 7.260(5) Angstrom and beta= 119.10(2) degrees. The structure may be described as an ordered intergrowth of slabs of Li2CuO2 and hypothetical LiCuO2 of NaCuO2 type. The formula suggests a copper (II,III) mixture, but there is only one crystallographic copper site

  • 4. GEJJI, SHRIDHAR P
    et al.
    HERMANSSON, KERSTI
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    LINDGREN, JAN
    ABINITIO VIBRATIONAL FREQUENCIES OF THE TRIFLATE ION, (CF3SO3)-1993In: J PHYS CHEM-US, ISSN 0022-3654, Vol. 97, no 15, p. 3712-3715Article in journal (Refereed)
    Abstract [en]

    The optimized geometry, harmonic vibrational frequencies and infrared intensities of the trifluoromethanesulfonate (triflate) ion, CF3SO3-, have been determined with ab initio self-consistent Hartree-Fock theory by using 3-21G* and 6-31G* Gaussian basis sets. Second-order Moller-Plesset perturbation calculations were also carried out with 6-31G* basis. A normal mode analysis shows that the vibrations assigned as symmetric and antisymmetric CF3 stretching involve other internal coordinates as well, viz., CF3 bending and CS stretching. The corresponding SO3 stretching modes, on the other hand, are almost entirely described with SO stretching coordinates. The assignments of the symmetric and antisymmetric SO3 and CF3 stretching vibrations from Moller-Plesset theory are seen to be different from those reported in the literature. Recent infrared spectroscopic experiments of the triflate ion coordinated to the zinc or lead ion in poly(ethylene oxide) complexes support the conclusions from second-order perturbation theory. The vibrational frequencies and infrared intensities show a strong dependence on basis set and electron correlation.

  • 5. GEJJI, SHRIDHAR P
    et al.
    HERMANSSON, KERSTI
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    LINDGREN, JAN
    AB-INITIO VIBRATIONAL FREQUENCIES OF THE TRIFLIC ACID MOLECULE1993In: J PHYS CHEM-US, ISSN 0022-3654, Vol. 97, no 27, p. 6986-6989Article in journal (Refereed)
    Abstract [en]

    The optimized geometry, harmonic vibrational frequencies, and infrared intensities of the trifluoromethanesulfonic (triflic) acid, CF3SO2OH, have been determined by ab initio self-consistent Hartree-Fock calculations and second-order Moller-Plesset perturbation theory with 6-31G** and lower basis sets. The optimized geometry of the triflic acid molecule is in good agreement with that reported from electron diffraction experiments. The overall symmetry for the molecule, however, is C1, and not C(s) as suggested from the experiments. The symmetric CF3 and SO2 stretching vibrational modes of the triflic acid are seen to be reversed compared to the assignment from the infrared spectra, reported earlier in the literature. The CF3 stretchings and the O=S=O bending normal modes include strong couplings of different internal coordinates. The vibrational frequencies and the infrared intensities are sensitive to the basis set choice as well as to electron correlation effects.

  • 6. GEJJI, SHRIDHAR P
    et al.
    HERMANSSON, KERSTI
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    TEGENFELDT, JÖRGEN
    LINDGREN, JAN
    GEOMETRY AND VIBRATIONAL FREQUENCIES OF THE LITHIUM TRIFLATE ION-PAIR - AN AB-INITIO STUDY1993In: J PHYS CHEM-US, ISSN 0022-3654, Vol. 97, no 44, p. 11402-11407Article in journal (Refereed)
    Abstract [en]

    The optimized geometry, harmonic vibrational frequencies, and infrared absorption intensities of the lithium trifluoromethanesulfonate (triflate) ion pair, CF3SO3-Li have been investigated using the ab initio self-consistent Hartree-Fock and correlated second-order Moller-Plesset perturbation theory with the 6-31G* and lower basis sets. In the optimized structure the lithium cation is bound to two of the oxygens of the SO3 group forming a bidentate complex with C(s) symmetry. A local minimum with a monodentate structure was obtained in the HF/3-21G* calculations. The energy difference between the mono- and bidentate structures of the complex is predicted to be nearly 39 kJ mol-1 in this basis. A splitting of 230 and 158 cm-1 is obtained for the antisymmetric SO3 stretching for the bi- and monodentate coordination of the lithium cation with the free anion, respectively. The infrared spectrum of lithium triflate in poly(propylene oxide) shows a splitting of 43 cm-1. The strong interaction of the metal cation with the anion in the 1:1 complex thus overemphasizes the ''splitting behavior'' observed for lithium triflate dissolved in polymers. In the bidentate (MP2/6-31G*) complex the symmetric SO3 stretching shows a downshift of 38 cm-1, in contrast to an upshift of 47 cm-1 for the monodentate complex. The different signs of these frequency shifts have a purely geometric origin. The dependence of this frequency shift on the position of the Li+ ion is discussed.

  • 7.
    HERMANSSON, KERSTI
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    COORDINATION EFFECTS ON THE STRETCHING VIBRATION OF THE OH- ION1993In: Chemical Physics, ISSN 0301-0104, E-ISSN 1873-4421, Vol. 170, no 2, p. 177-184Article in journal (Refereed)
    Abstract [en]

    IR and Raman measurements on crystalline hydroxides reported in the literature have shown that both frequency upshifts and downshifts with respect to the free-ion frequency occur. Here the fundamental stretching vibrational frequency of a bound OH- ion in different point charge environments has been examined by ab initio calculations at the MP2 level. For a given geometry of a q+ . OH- . q- complex, the ab initio frequency is found to vary in a systematic way as the electric field is increased: the frequency increases, passes through a maximum and then decreases. Both the value of the maximum frequency and the field strength at which it occurs are highly dependent on the geometry of the complex. Only the field component parallel to the OH- axis is effective in changing the OH frequency. The arc-like shape of the frequency versus field correlation curves ''explains'' the large degree of non-additivity found for the environment-induced frequency shifts. H-bonds donated by the OH- ion may, or may not, lead to a frequency downshift, depending on the other neighbours present. It is also shown that a model which explicitly takes the field inhomogeneity into account (by a simple polynomial in E(parallel-to), (E(parallel-to))2, E(parallel-to)', (E(parallel-to)')2 and cross-terms, evaluated at two different ''probing sites'' in the ion), manages to represent the OH- frequency shift for an ''arbitrary'' point-charge environment.

  • 8.
    HERMANSSON, KERSTI
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    ELECTRIC-FIELD EFFECTS ON THE OH VIBRATIONAL FREQUENCY AND INFRARED-ABSORPTION INTENSITY FOR WATER1993In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 99, no 2, p. 861-868Article in journal (Refereed)
    Abstract [en]

    The variations of the anharmonic OH frequency and the infrared absorption intensity with field strength have been calculated for the uncoupled OH stretching vibration of a water molecule in a static, homogeneous electric field using ab initio methods at the MP4 level with a nearly saturated basis set. The OH frequency is found to be virtually independent of the field components perpendicular to the vibrating OH bond. For the parallel component, the frequency vs field curve is close to quadratic, with a maximum for a slightly negative (directed from H to 0) field strength. The external field perturbation, defined as V(ext)(E(parallel-to), r(OH)) = V(tot)(E(parallel-to), r(OH)) - V(free)(r(OH)), is found to be closely linear in r(OH), except when the field strength Ell is both large and negative. The linear external force constant is almost perfectly accounted for by the sum of two terms, -E(parallel-to).dmu(parallel-to)free/dr(OH) and -1/2.E(parallel-to).partial derivative mu(parallel-to)induced/partial derivative r(OH). These derivatives are quite insensitive to the choice of basis-set. The partial derivative mu(parallel-to)induced/partial derivative r(OH) derivative is approximately proportional to E(parallel-to), and gives rise to the arclike shape of the frequency vs field curve. The frequency maximum occurs where partial derivative mu(parallel-to)tot/partial derivative r(OH) almost-equal-to 0. It is the sign of dmu(parallel-to)free/dr(OH) which determines that the frequency maximum occurs at a negative field strength for water (but at a positive field strength for OH-, for example), i.e., that a frequency red-shift (blue-shift for OH-) occurs when the molecule is bound. The linear relationship between the infrared absorption intensity and frequency of the water OH vibration is derived.

  • 9.
    HERMANSSON, KERSTI
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    REDSHIFTS AND BLUESHIFTS OF OH VIBRATIONS1993In: International Journal of Quantum Chemistry, ISSN 0020-7608, E-ISSN 1097-461X, Vol. 45, no 6, p. 747-758Article in journal (Refereed)
    Abstract [en]

    Ab initio calculations of potential energy, dipole moment, equilibrium OH distance, force constants, and anharmonic frequencies, and correlation between these quantities, are presented for a water molecule and an OH- ion in a uniform electric field of varying field strength. It is explained why a bound H2O molecule in nature always experiences a frequency downshift with respect to the free molecule, and a bound OH-1 ion, either a downshift or an upshift. The frequency-field variation is well accounted for by the expression DELTAnu(OH) is-proportional-to -E(parallel-to) . (dmu(parallel-to)free/dr(OH) + 1/2 . partial derivative mu(parallel-to)induced/partial derivative r(OH)). A frequency maximum occurs at the field strength where partial derivative mu(parallel-to)tot/partial derivative r(OH) is similar to 0. Two cases can be discerned: (1) the frequency maximum falls at a positive field strength when dmu(parallel-to)free/dr(OH) is positive (this is the situation for OH-), and (2) the maximum frequency falls at a negative field when dmu(parallel-to)free/dr(OH) is negative (this occurs for water). In general, for an OH bond in a bonding situation where the intermolecular interactions are dominated by electrostatic forces, the nonlinearity of the frequency shift with respect to an applied field is governed by how close to the frequency maximum one is, i.e., by both dmu(parallel-to)free/dr(OH) and partial derivative mu(parallel-to)induced/partial derivative r(OH). Correlation curves between the external linear force constant, k(ext), and r(OH,e) are closely linear over the whole field range studied here, whereas the frequency vs. r(OH,e) and force constants vs. r(OH,e) correlation curves form two approximately linear, parallel branches, corresponding to ''before'' and ''after'' the maximum in the frequency vs. field curves. Each branch of the nu vs. r(OH,e) curves has a slope of approximately -16,000 cm-1/angstrom.

  • 10. KNUTS, SÖREN
    et al.
    OJAMAE, LARS
    HERMANSSON, KERSTI
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    AN AB-INITIO STUDY OF THE OH STRETCHING FREQUENCIES IN ICE-II, ICE-VIII, AND ICE-IX1993In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 99, no 4, p. 2917-2928Article in journal (Refereed)
    Abstract [en]

    Ab initio studies of the uncoupled, anharmonic OH and OD stretching frequency shifts in the three proton-ordered ice phases known, ice II, ice VIII, and ice IX, are presented. The ice structures are simulated by (H2O)5 supermolecules surrounded by point charges representing the correct crystal potentials. The calculations include electron correlation at the MP2 (DZP) level. For the eight different OH (OD) vibrators studied, the crystal environment leads to a downshift of the anharmonic OD frequency in the range 195-265 cm-1, in good agreement with experimental values (222-281 cm-1) when corrections are made for the limited supermolecular size (approximately - 45 cm-1), and, for ice VIII, also for the effects of the nonhydrogen bonded network (approximately + 75 cm- 1). Also the agreement between absolute experimental and theoretical OD frequencies is good when errors due to basis set limitation (approximately - 75 cm-1 ) are taken into account. The calculations suggest a reassignment of two of the experimental OD bands in ice II and all three experimental OD bands in ice IX. Calculations for charge-embedded (H2O)9 and (H2O)13 ice clusters show that at least a nonamer is needed to avoid boundary effects from the size of the supermolecule. Theoretical correlation curves between H-bond parameters-R (O ... 0), nu(OH), r(e)(OH), and infrared absorption intensity-are presented for the three ice phases and are compared to liquid water computations.

  • 11. Kolb, Hartmuth
    et al.
    Andersson, Pher
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Bennani, Youssef
    Crispino, Gerard
    Jeong, Kyu-Sung
    Kwong, Hoi-Lun
    Sharpless, K. Barry
    On1993In: J. Am. Chem. Soc., no 115, p. 12226-12227Article in journal (Refereed)
  • 12. LINDGREN, JAN
    et al.
    HERMANSSON, KERSTI
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    WOJCIK, MAREK J
    THEORETICAL SIMULATION AND EXPERIMENTAL-DETERMINATION OF OH AND OD STRETCHING BANDS OF ISOTOPICALLY DILUTED HDO MOLECULES IN AQUEOUS-ELECTROLYTE SOLUTIONS1993In: J PHYS CHEM-US, ISSN 0022-3654, Vol. 97, no 20, p. 5254-5259Article in journal (Refereed)
    Abstract [en]

    A combined theoretical and experimental study of the hydration of ions in aqueous electrolyte solutions is presented. Theoretical simulations of OH and OD stretching bands of isotopically diluted HDO molecules in a 0.44 m lithium formate solution have been performed. The positions of the atoms of the water molecules and the ions were taken from the trajectory file of a rigid-molecule room-temperature molecular dynamics simulation. V(r(OH)) potential energy functions were constructed as a sum of intra- and intermolecular energies and used in a variational calculation of the vibrational energy levels. Vibrational transition densities of states were calculated for HDO molecules in the first and second hydration shells of the ions. Infrared spectra of isotopically isolated HDO molecules in aqueous solutions of NaHCOO, LiClO4, NaClO4, Ca(ClO4)2, and Sr(ClO4)2 have been registered. The spectra were evaluated using an earlier developed double-difference method, where the number of ion-affected water molecules enters as a parameter in the analysis. In the present work, this number is obtained from the theoretical calculations, both for the Li+ and the HCOO- ion hydration. We find that OH/OD groups of water molecules in the second hydration shell of Li+, hydrogen-bonded to the first hydration shell, are affected by the ion. The earlier observed division of IR stretching frequencies for HDO molecules around cations into two distinct groups can now be explained by the presence or absence of such second-hydration-shell water molecules. For HDO molecules hydrogen-bonded to the HCOO- ions, the OH/OD frequency is lowered, compared to bulk water, for the OH/OD group involved in H-bonding to the ion, whereas the frequency is increased for the other OD/OH group, pointing away from the ion. The frequencies of HDO molecules surrounding the CH end of the formate ion are not influenced by the ion.

  • 13. Morikawa, Kouhei
    et al.
    Park, Jeonghan
    Andersson, Pher
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Hashiyama, Tomiki
    Sharpless, K. Barry
    Catalytic Asymmetric Dihydroxylation of Tetrasubstituted Oelfins1993In: J. Am. Chem. Soc., no 115, p. 8463-8464Article in journal (Refereed)
  • 14. Murakami, Masahiro
    et al.
    Suginome, Michinori
    Fujimoto, Kenzo
    Nakamura, Hiroshi
    Andersson, Pher
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Ito, Yoshihiko
    Stereoselective Intramolecular Bis-Silylation of Alkenes Promoted by a Palladium-Isocyanide Catalyst Leading to Polyol Synthesis1993In: Stereoselective Intramolecular Bis-Silylation of Alkenes Promoted by a Palladium-Isocyanide Catalsyst Leading to Polyol Synthesis, no 115, p. 6487-6498Article in journal (Refereed)
  • 15. Nilsson, Ylva I. M.
    et al.
    Andersson, Pher
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Bäckvall, Jan-E.
    Example of Theromodynamic Control in Palladium-Catalyzed Allylic Alkylation. Evidence for Palladium-Assisted Allylic C-C Bond Cleavage1993In: J. Am. Chem. Soc., no 115, p. 6609-6613Article in journal (Refereed)
  • 16. WOJCIK, MAREK J
    et al.
    HERMANSSON, KERSTI
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    LINDGREN, JAN
    OJAMAE, LARS
    THEORETICAL SIMULATION OF OH AND OD STRETCHING BANDS OF ISOTOPICALLY DILUTED HDO MOLECULES IN AQUEOUS-SOLUTION1993In: Chemical Physics, ISSN 0301-0104, E-ISSN 1873-4421, Vol. 171, no 1-2, p. 189-201Article in journal (Refereed)
    Abstract [en]

    Uncoupled OH and OD stretching bands of HDO molecules have been calculated for an ionic aqueous solution, based on the trajectories from a classical statistical-mechanical computer simulation and subsequent quantum-mechanical calculations of the vibrational energy levels. Each V(r(OH)) potential function has been constructed as a sum of intra- and intermolecular energies, where different intermolecular water-water potential functions from the literature (MCY, TIPS2, RWK2 and CF2) have been tested in conjunction with the experimentally derived HMS intramolecular potential. In this way, vibrational densities-of-states as well as infrared absorption bands have been calculated for HDO molecules in the bulk and in the ionic hydration shells (Li+, HCOO-). Calculated frequencies and band widths for the TIPS2 and MCY potentials are fairly close to experimental values. The calculated OH shift between the gas and liquid water phases is - 303 cm-1 with the TIPS2 potential, as compared to the experimental value of - 307 cm-1. The MCY potential gives - 260 cm-1, while RWK2 as well as the CF2 potentials give rise to a non-negligible number of spurious frequencies. Water molecules in the first hydration shell of Li+ exhibit only slightly lower stretching frequencies than bulk water. The frequencies of the OH and OD groups of HDO molecules bonded to the formate oxygen atoms are lower than in bulk water, while the frequency of the OH/OD group pointing away from the formate ion is higher compared to bulk water.

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