... THE MYRIOPHYLLUM SPICATUM GROUP IN NORTH EUROPE Knut Faegri, Knut Faegri Botanisk Institutt, Universitetet i Bergen, Postbox 12, ... NorwaySearch for more papers by this author Knut Faegri, Knut Faegri Botanisk Institutt, Universitetet i Bergen, Postbox 12, N- ...
Tópico(s): Mycorrhizal Fungi and Plant Interactions
1982 - Wiley | Taxon
... AND FORM GENERA: SIGNIFICANCE AND NOMENCLATURAL TREATMENT Knut Faegri, Knut Faegri Bergen, NorwayThe author has had the inestimable ... Search for more papers by this author Knut Faegri, Knut Faegri Bergen, NorwayThe author has had the inestimable advantage ...
Tópico(s): Historical and Archaeological Studies
1963 - Wiley | Taxon
... RepertoriumVolume 88, Issue 4 p. 302-304 Buchbesprechung Faegri, Knut & Iversen, Jons., Textbook of Pollen Analysis. Third revised edition by K. Faegri. 295 Seiten, 31 Abb., 13 Tab. Munksgaard Copenhagen, ...
Tópico(s): Botany and Plant Ecology Studies
1977 - Wiley | Feddes Repertorium
... Siedlung. Bulletin Geological Society China 8: 363– 365. Faegri, Knut, and Johannes Iverson 1975 Textbook of Pollen Analysis. ...
Tópico(s): Silicon Effects in Agriculture
1982 - Wiley | American Anthropologist
Jan Almløf, Knut Fægri, Knut Korsell,
Abstract The principles and structure of an LCAO ‐ MO ab ‐ initio computer program which recalculates all two‐electron integrals needed in each SCF iteration are formulated and discussed. This approach—termed “direct SCF ”—is found to be particularly efficient for calculations on very large systems, and also for calcuations on small and medium‐sized molecules with modern minicomputers. The time requirements for a number of sample calculations are listed, and the distribution of two‐electron integrals according ...
Tópico(s): Lanthanide and Transition Metal Complexes
1982 - Wiley | Journal of Computational Chemistry
I. K. Ferguson, Knut Fægri, Johannes Iversen, Knut Fægri,
Tópico(s): Lichen and fungal ecology
1976 - Springer Science+Business Media | Kew Bulletin
Richard Blom, Knut Fægri, Tonje Midtgaard,
... RETURN TO ISSUEPREVArticleNEXTAdduct influences on (cyclopentadienyl)lithiumRichard Blom, Knut Faegri Jr., and Tonje MidtgaardCite this: J. Am. Chem. ...
Tópico(s): Organometallic Complex Synthesis and Catalysis
1991 - American Chemical Society | Journal of the American Chemical Society
Richard Blom, Knut Fægri, Hans V. Volden,
... metallocenes: electron diffraction and ab initio investigationsRichard Blom, Knut Faegri Jr., and Hans V. VoldenCite this: Organometallics 1990, ...
Tópico(s): Electron and X-Ray Spectroscopy Techniques
1990 - American Chemical Society | Organometallics
Richard A. Andersen, Knut Fægri, Jennifer C. Green, Arne Haaland, Michael F. Läppert, W.‐P. LEUNG, Kristin Rypdal,
... cobalt): two-coordinate transition-metal amidesR. A. Andersen, Knut Faegri Jr., Jennifer C. Green, Arne Haaland, M. F. ...
Tópico(s): Synthesis and characterization of novel inorganic/organometallic compounds
1988 - American Chemical Society | Inorganic Chemistry
Ole Swang, Knut Fægri, Odd Gropen,
... Activation by Re, Os, Ir, and PtOle Swang, Knut Faegri Jr., and Odd GropenCite this: J. Phys. Chem. ...
Tópico(s): Catalysts for Methane Reforming
1994 - American Chemical Society | The Journal of Physical Chemistry
... as determined by ab initio calculationsJan Almloef and Knut Faegri Jr.Cite this: J. Am. Chem. Soc. 1983, ...
Tópico(s): Photochemistry and Electron Transfer Studies
1983 - American Chemical Society | Journal of the American Chemical Society
Norbert Holstein, Marc Gottschling,
... Solanum (Solanaceae) defining the "solanoid" flower type by Knut Fægri. The flowers of buzz-pollinated, Australian Halgania resemble ... the concept of solanoid flowers as defined by Knut Fægri.
Tópico(s): African Botany and Ecology Studies
2017 - Elsevier BV | Flora
... a major advance occurred with the publication by Knut Fægri and Johs Iversen of their Text-book of ...
Tópico(s): Geology and Paleoclimatology Research
2019 - Taylor & Francis | Plant Ecology & Diversity
Sébastien Dubillard, J.-B. Rota, Trond Saue, Knut Fægri,
We report the implementation of Pipek-Mezey [J. Chem. Phys. 90, 4916 (1989)] localization of molecular orbitals in the framework of a four-component relativistic molecular electronic structure theory. We have used an exponential parametrization of orbital rotations which allows the use of unconstrained optimization techniques. We demonstrate the strong basis set dependence of the Pipek-Mezey localization criterion and how it can be eliminated. We have employed localization in conjunction with projection ...
Tópico(s): Advanced Chemical Physics Studies
2006 - American Institute of Physics | The Journal of Chemical Physics
Tópico(s): Inorganic Fluorides and Related Compounds
2004 - Elsevier BV | Chemical Physics
Michael Seth, Peter Schwerdtfeger, Knut Fægri,
The chemistry of element 113 is investigated by theoretical methods. The results of fully relativistic calculations for (113)H and (113)F are compared with those derived by other techniques to obtain an indication of the accuracy of the more approximate models as well as the importance of including scalar and/or spin–orbit relativistic effects. Both of these effects are found to be important. The spin–orbit coupled pseudopotential approximation yields results of satisfactory accuracy, but the two ...
Tópico(s): Atomic and Molecular Physics
1999 - American Institute of Physics | The Journal of Chemical Physics
Vladimı́r Kellö, Andrzej J. Sadlej, Knut Fægri,
In order to resolve some puzzling discrepancies between theoretical and experimental dipole moment data for oxides of the Group IVa metals a series of nonrelativistic and relativistic high-level-correlated calculations have been performed for SnO and PbO. The same methods have been used to calculate the dipole moments of SnS and PbS for which the earlier results were found to be in reasonable agreement with experiment. The main attention of the present study has been focused on the treatment of ...
Tópico(s): Spectroscopy and Quantum Chemical Studies
1998 - American Institute of Physics | The Journal of Chemical Physics
Michael Seth, Knut Fægri, Peter Schwerdtfeger,
The stability of the oxidation state +4 decreases from silicon to element 114, as shown by relativistic and nonrelativistic calculations on the hydrides, fluorides, and chlorides of the Group 14 elements (the energies of the decomposition reaction (1) are given in the plot). Thus it is unlikely that superheavy element 114, which may have stable isotopes due to its magic numbers of protons and neutrons, can be studied by atom-at-a-time chemistry in the oxidation state +4.
Tópico(s): Catalysis and Oxidation Reactions
1998 - Wiley | Angewandte Chemie International Edition
Jon K. Laerdahl, Knut Fægri, Lucas Visscher, Trond Saue,
Fully relativistic four-component self-consistent field and correlated calculations at the Mo/ller–Plesset second-order perturbation theory level (MP2) have been performed for the monofluorides and mono- and trihydrides of lanthanum, lutetium, actinium, and lawrencium. The calculated spectroscopic constants are in good agreement with available experimental data. The calculated bond lengths have been compared with values from nonrelativistic calculations to give an estimate of the effect of relativity ...
Tópico(s): Inorganic Fluorides and Related Compounds
1998 - American Institute of Physics | The Journal of Chemical Physics
Harry M. Quiney, Jon K. Laerdahl, Knut Fægri, Trond Saue,
The theory of $\mathrm{PT}$-odd interactions relevant to existing experimental measurements of the hyperfine structure of TlF is reviewed. We outline a relativistic electronic structure theory based on single-particle four-component Dirac spinors, and implemented using methods borrowed from ab initio quantum chemistry. Numerical calculations are reported of the electronic structure of TlF, some of its chemical properties, and of its $\mathrm{PT}$-odd electronic matrix elements. From these results, and ...
Tópico(s): Inorganic Chemistry and Materials
1998 - American Physical Society | Physical Review A
Jon K. Laerdahl, Trond Saue, Knut Fægri, Harry M. Quiney,
Ab initio Dirac-Fock calculations of PT-odd interactions in TlF are reported which employ large sets of kinetically balanced Gaussian basis functions. Revised estimates are reported of bounds on the value of the electric dipole moment of the proton, ${d}_{p}$, the tensor-pseudotensor coupling constant, ${C}_{T}$, and the Schiff moment of the ${}^{205}$Tl nucleus, Q, based on analysis of existing experimental data.
Tópico(s): Atomic and Molecular Physics
1997 - American Physical Society | Physical Review Letters
Knut Fægri, Arne Haaland, Kjell-Gunnar Martinsen, T. G. Strand, Hans V. Volden, Ole Swang, Carlaxel Anderson, Christina Persson, Sandra Bogdanović, Wolfgang A. Herrmann,
The molecular structure of TaCl 5 has been optimised under D 3h symmetry by density-functional theory calculations. Calculation of the molecular force field and vibrational frequencies showed that the optimised structure corresponds to a minimum on the full potential energy surface. Gas electron diffraction data of MCl 5 (M = Ta, W or Re), recorded with nozzle temperatures ranging from 130 to 210 °C, showed that WCl 5 and ReCl 5 are trigonal bipyramidal like TaCl 5 . Structure refinements based on molecular ...
Tópico(s): Crystallography and molecular interactions
1997 - Royal Society of Chemistry | Journal of the Chemical Society. Dalton transactions
Jon K. Laerdahl, Trond Saue, Knut Fægri,
Tópico(s): Nuclear physics research studies
1997 - Springer Science+Business Media | Theoretical Chemistry Accounts
Trond Saue, Knut Fægri, Trygve Helgaker, Odd Gropen,
A theory of 4-component direct SCF calculations is presented using a quaternion formulation of the Dirac–Fock equations. Screening of integral batches is supplemented with screening on individual integrals and with separate screening of Coulomb and exchange contributions to the Fock matrix. The direct SCF method is applied to study bonding in caesium auride. The caesium–gold bond is found to be highly ionic, with gold present as the anion. A relativistic bond contraction of 41 pm is observed.
Tópico(s): Synthesis and characterization of novel inorganic/organometallic compounds
1997 - Taylor & Francis | Molecular Physics
Hans Jørgen Aa. Jensen, Kenneth G. Dyall, Trond Saue, Knut Fægri,
A formalism for relativistic four-component multiconfigurational self-consistent-field calculations on molecules is presented. The formalism parallels a direct second-order restricted-step algorithm developed for nonrelativistic molecular calculations. The presentation here focuses on the differences required by the use of the Dirac Hamiltonian with the incorporation of time-reversal symmetry and point group symmetry for D2h and subgroups, providing the expressions in this framework which correspond ...
Tópico(s): Advanced Physical and Chemical Molecular Interactions
1996 - American Institute of Physics | The Journal of Chemical Physics
Kenneth G. Dyalll, Knut Fægri,
Tópico(s): Advanced Chemical Physics Studies
1996 - Springer Science+Business Media | Theoretica Chimica Acta
Michael Seth, Peter Schwerdtfeger, Michael Dolg, Knut Fægri, Bernd A. Heß, Uzi Kaldor,
Relativistic and electron correlation contributions in the hydride of the recently discovered superheavy element 111 were studied using ab-initio methods within different relativistic approaches. Relativistic effects decrease the (111)H bond distance by 0.42 Å. As a result of this large bond contraction, the bond distance of (111)H (1.51 Å) is comparable to that of the hydride of its lighter congener AuH (1.52 Å), but below that of AgH (1.60 Å). The dissociation energy is relativistically increased by ...
Tópico(s): Nuclear physics research studies
1996 - Elsevier BV | Chemical Physics Letters
Ole Swang, Richard Blom, Olav B. Ryan, Knut Fægri,
The solvation of palladium diacetate in trifluoroacetic acid has been studied by ab initio quantum chemical calculations and infrared and NMR spectroscopy. We report evidence for the formation of a dicarboxylate−dicarboxylic acid species, with square planar coordination around the metal center, through addition of two acid molecules.
Tópico(s): Advanced Chemical Physics Studies
1996 - American Chemical Society | The Journal of Physical Chemistry
Trond Saue, Knut Fægri, Odd Gropen,
The bonding in the hydrogen halides HI, HAt and HUus (Uus = element 117) has been studied using four-component Dirac-Hartree-Fock calculations and finite basis sets. The calculations show that the effect of spin-orbit splitting on the valence p-orbital dominates the bonding for the compound of the superheavy element, and even for the sixth row the spin-orbit interaction should be treated self-consistently for an accurate description of the electronic structure.
Tópico(s): Nuclear physics research studies
1996 - Elsevier BV | Chemical Physics Letters
Vladimı́r Kellö, Andrzej J. Sadlej, Knut Fægri,
Electric-dipole polarizabilities of K, Rb, Cs, and Fr are calculated in the framework of the quasirelativistic method based on mass-velocity and Darwin terms in the Pauli Hamiltonian. The electron-correlation contribution due to atomic cores is taken into account at two levels of approximation. The next-to-valence-shell contributions follow from the appropriate complete active-space multiconfiguration self-consistent-field calculations while the remaining core correlation effects are evaluated by ...
Tópico(s): Inorganic Fluorides and Related Compounds
1993 - American Physical Society | Physical Review A