Viser treff 214-233 av 527

    • Gauge-origin independent calculations of electric-field-induced second-harmonic generation circular intensity difference using London atomic orbitals 

      Anelli, Marco; Ringholm, Magnus; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2017)
      We present the first gauge-origin independent calculations of the circular intensity difference (CID) in electric-field-induced second-harmonic generation (EFISHG), including all contributions up to the electric-quadrupole–magnetic-dipole level. A recursive, open-ended response theory framework in combination with the use of London atomic orbitals allows us to ensure gauge-origin independent results. ...
    • Gauge-origin independent calculations of Jones birefringence 

      Shcherbin, Dmitri; Thorvaldsen, Andreas johan; Jonsson, Dan Johan; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2011)
      We present the first gauge-origin independent formulation of Jones birefringence at the Hartree–Fock level of theory. Gauge-origin independence is achieved through the use of London atomic orbitals. The implementation is based on a recently proposed atomic orbital-based response theory formulation that allows for the use of both time- and perturbation-dependent basis sets [Thorvaldsen, Ruud, Kristensen, ...
    • General recurrence-relation generation scheme for molecular integral evaluation 

      Gao, Bin (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-09-24)
      We develop a new scheme for evaluating different molecular integrals using Gaussian type orbitals. In this new scheme, the evaluation of integrals is performed in two steps during runtime. The first step is a top-down procedure that maps each recurrence relation into a jagged array (array of arrays), where each element of a member array represents either the final results or some intermediate integrals ...
    • Generalization of Intrinsic Orbitals to Kramers-Paired Quaternion Spinors, Molecular Fragments, and Valence Virtual Spinors 

      Senjean, Bruno; Sen, Souloke; Repisky, Michal; Knizia, Gerald; Visscher, Lucas (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-08)
      Localization of molecular orbitals finds its importance in the representation of chemical bonding (and antibonding) and in the local correlation treatments beyond mean-field approximation. In this paper, we generalize the intrinsic atomic and bonding orbitals [G. Knizia, J. Chem. Theory Comput. 2013, 9, 11, 4834–4843] to relativistic applications using complex and quaternion spinors, as well as to ...
    • A generalized few-state model for the first hyperpolarizability 

      Alam, MD Mehboob; Beerepoot, Maarten; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-22)
      The properties of molecules depend on their chemical structure, and thus, structure–property relations help design molecules with desired properties. Few-state models are often used to interpret experimental observations of non-linear optical properties. Not only the magnitude but also the relative orientation of the transition dipole moment vectors is needed for few-state models of the non-linear ...
    • Genome mapping of seed-borne allergens and immunoresponsive proteins in wheat 

      Juhasz, Angela; Belova, Tatiana; Florides, Chris G; Maulis, Csaba; Fischer, Iris; Gell, Gyongyver; Birinyi, Zsofia; Ong, Jamie; Keeble-Gagnere, Gabriel; Maharajan, Amudha Deepalakshmi; Ma, Wujun; Gibson, Peter; Jia, Jizeng; Lang, Daniel; Mayer, Klaus F X; Spannagl, Manuel; Tye-Din, Jason A.; Appels, Rudi; Olsen, Odd-Arne (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-08-17)
      Wheat is an important staple grain for humankind globally because of its end-use quality and nutritional properties and its adaptability to diverse climates. For a small proportion of the population, specific wheat proteins can trigger adverse immune responses and clinical manifestations such as celiac disease, wheat allergy, baker’s asthma, and wheat-dependent exercise-induced anaphylaxis (WDEIA). ...
    • Geometric Energy Derivatives at the Complete Basis Set Limit: Application to the Equilibrium Structure and Molecular Force Field of Formaldehyde 

      Morgan, W. James; Matthews, Devin A; Ringholm, Magnus; Agarwal, Jay; Gong, Justin Z; Ruud, Kenneth; Allen, Wesley D.; Stanton, John F.; Schaefer, Henry F. III (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-02-23)
      Geometric energy derivatives which rely on core-corrected focal-point energies extrapolated to the complete basis set (CBS) limit of coupled cluster theory with iterative and noniterative quadruple excitations, CCSDTQ and CCSDT(Q), are used as elements of molecular gradients and, in the case of CCSDT(Q), expansion coefficients of an anharmonic force field. These gradients are used to determine the ...
    • Gold dipyrrin-bisphenolates: A combined experimental and DFT study of metal-ligand interactions 

      Thomas, Kolle E; Desbois, Nicolas; Conradie, Jeanet; Teat, Simon J.; Gros, Claude P; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-02)
      Given that noninnocent and metalloradical-type electronic structures are ubiquitous among dipyrrin-bisphenolate (DPP) complexes, we synthesized the gold(III) derivatives as potentially innocent paradigms against which the properties of other metallo-DPP derivatives can be evaluated. Electronic absorption spectra, electrochemical studies, a single-crystal X-ray structure, and DFT calculations all ...
    • Goldilocks Dilemma: LPS Works Both as the Initial Target and a Barrier for the Antimicrobial Action of Cationic AMPs on E. coli 

      Jakubec, Martin; Rylandsholm, Fredrik G.; Rainsford, Philip; Silk, Mitchell; Bril'kov, Maxim; Kristoffersen, Tone; Juskewitz, Eric; Ericson, Johanna U; Svendsen, John Sigurd Mjøen (Journal article; Tidsskriftartikkel, 2023-07-20)
      Antimicrobial peptides (AMPs) are generally membrane-active compounds that physically disrupt bacterial membranes. Despite extensive research, the precise mode of action of AMPs is still a topic of great debate. This work demonstrates that the initial interaction between the Gram-negative E. coli and AMPs is driven by lipopolysaccharides (LPS) that act as kinetic barriers for the binding of AMPs to ...
    • A Green, Scalable, and Catalyst-Free One-Minute Synthesis of Quinoxalines 

      Elumalai, Vijayaragavan; Hansen, Jørn H (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-10)
      A highly efficient and catalyst-free protocol is reported for the synthesis of quinoxalines via the classical cyclocondensation reaction between aryldiamines and dicarbonyl compounds. Remarkably simple and green reaction conditions employing methanol as solvent afforded medium to excellent yield of quinoxalines after only one-minute reaction time at ambient temperature. The conditions allow at least ...
    • A Green, Scalable, One-Minute Synthesis of Benzimidazoles 

      Elumalai, Vijayaragavan; Hansen, Jørn H (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-24)
      Herein is reported a substantially improved synthesis of 2-substituted benzimidazoles by condensation of 1,2-diaminoarenes and aldehydes using methanol as the reaction medium. The developed method afforded moderate to excellent yields (33-96%) at ambient temperature, displays high functional group tolerance, is conducted open to air, and requires only one-minute reaction time under catalyst- ...
    • Gruppelærerdagen – trygghet og kvalitet fra første undervisningstime 

      Huru, Hilja Lisa; Beerepoot, Maarten (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-24)
      En stor del av undervisningen i realfagene ved norske universiteter blir utført av stipendiater eller studenter fra tidligere kull. Fokus på opplæring av denne gruppen undervisere kan bidra til en positiv effekt på undervisningskvalitet og studentenes læring. Det varierer imidlertid fra institusjon til institusjon om det finnes en slik type opplæring og omfang og kvalitet på denne opplæringen kan ...
    • Gruppelærerdagen – undervisningskvalitet fra første time 

      Beerepoot, Maarten; Huru, Hilja Lisa (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-04-25)
      Ved norske universiteter er det vanlig at stipendiater eller studenter fra tidligere kull utfører en stor del av undervisningen innen realfagene. Fokus på opplæring av denne gruppen undervisere kan bidra til en positiv effekt på undervisningskvalitet og studentenes læring. Det varierer imidlertid fra institusjon til institusjon om det finnes en slik type opplæring, og omfang og kvalitet på ...
    • A Haar Wavelet-based Multi-resolution Representation Method of Time Series Data 

      Muhammad Fuad, Muhammad Marwan (Peer reviewed; Journal article; Tidsskriftartikkel, 2015-01-10)
      Similarity search of time series can be efficiently handled through a multi-resolution representation scheme which offers the possibility to use pre-computed distances that are calculated and stored at indexing time and then utilized at query time together with filters in the form of exclusion conditions which speed up the search. In this paper we introduce a new multi-resolution representation ...
    • Halogen Bonding: An Odd Chemistry? 

      Turunen, Lotta; Hansen, Jørn H; Erdélyi, Máté (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-05-03)
      Halogen bonding is a flourishing field of research, but has for long been little recognized. The same goes for its scientific hero, Odd Hassel, who laid the foundations for all current developments. The crystallographic observation of halogen−oxygen interatomic distances shorter than the sum of the van der Waals radii of the involved atoms, and the interpretation of this phenomenon as a charge-transfer ...
    • Harmonic Infrared and Raman Spectra in Molecular Environments Using the Polarizable Embedding Model 

      Dundas, Karen Oda Hjorth Minde; Beerepoot, Maarten T. P.; Ringholm, Magnus; Reine, Simen Sommerfelt; Bast, Radovan; List, Nanna Holmgaard; Kongsted, Jacob; Ruud, Kenneth; Olsen, Jógvan Magnus Haugaard (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-05-19)
      We present a fully analytic approach to calculate infrared (IR) and Raman spectra of molecules embedded in complex molecular environments modeled using the fragment-based polarizable embedding (PE) model. We provide the theory for the calculation of analytic second-order geometric derivatives of molecular energies and first-order geometric derivatives of electric dipole moments and dipole–dipole ...
    • Heavy-element–ligand covalence: ligand noninnocence in molybdenum and tungsten Viking-helmet Corroles 

      Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-10-07)
      Extensive DFT calculations with several exchange–correlation functionals indicate that molybdenum-dichlorido Viking helmet corroles are noninnocent with significant Mo<sup>IV</sup>-corrole<sup>˙2−</sup> character. The effect is mediated by a Mo(4d)-corrole(π) orbital interaction similar to that postulated for MnCl, FeCl and FeNO corroles. The effect also appears to operate in tungsten-dichlorido ...
    • Heterocyclic cellular lipid peroxidation inhibitors inspired by the marine antioxidant barettin 

      Labriere, Christophe; Andersen, Jeanette hammer; Albrigtsen, Marte; Hansen, Jørn H; Svenson, Johan (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-11-22)
      The marine environment remains a rich source for the discovery and development of novel bioactive compounds. The present paper describes the design, synthesis and biological evaluation of a library of small molecule heterocyclic mimetics of the marine 2,5-diketopiperazine barettin which is a powerful natural antioxidant. By mainly focusing on the influence from the brominated indole and heterocyclic ...
    • The high catalytic rate of the cold-active Vibrio alkaline phosphatase requires a hydrogen bonding network involving a large interface loop 

      Hjörleifsson, Jens Guðmundur; Helland, Ronny; Magnusdottir, Manuela; Ásgeirsson, Bjarni (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-11-16)
      The role of surface loops in mediating communication through residue networks is still a relatively poorly understood part in the study of cold adaptation of enzymes, especially in terms of their quaternary interactions. Alkaline phosphatase (AP) from the psychrophilic marine bacterium <i>Vibrio splendidus</i> (VAP) is characterized by an analogous large surface loop in each monomer, referred to as ...
    • High natural PHA production from acetate in Cobetia sp. MC34 and Cobetia marina DSM 4741T and in silico analyses of the genus specific PhaC2 polymerase variant 

      Christensen, Mikkel; Jablonski, Piotr; Altermark, Bjørn; Irgum, Knut; Hansen, Hilde (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-12-20)
      Background: Several members of the bacterial Halomonadacea family are natural producers of polyhydroxyalkanoates (PHA), which are promising materials for use as biodegradable bioplastics. Type-strain species of Cobetia are designated PHA positive, and recent studies have demonstrated relatively high PHA production for a few strains within this genus. Industrially relevant PHA producers may therefore ...