Viser treff 207-226 av 527

    • Four-component relativistic time-dependent density-functional theory using a stable noncollinear DFT ansatz applicable to both closed- and open-shell systems 

      Komorovsky, Stanislav; Cherry, Peter J.; Repisky, Michal (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11-14)
      We present a formulation of relativistic linear response time-dependent density functional theory for the calculation of electronic excitation energies in the framework of the four-component Dirac-Coulomb Hamiltonian. This approach is based on the noncollinear <i>ansatz</i> originally developed by Scalmani and Frisch [J. Chem. Theory Comput. 8, 2193 (2012)] and improves upon the past treatment of ...
    • Fragment-Based Drug Discovery 

      Lund, Bjarte Aarmo (Journal article; Tidsskriftartikkel, 2015-06-13)
    • Free-Base Corrole Anion 

      Tarai, Arup; Mallick, Jyotiprakash; Conradie, Jeanet; Kar, Sanjib; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-08-30)
      Free-base corroles have long been known to be acidic, readily undergoing deprotonation by mild bases and in polar solvents. The conjugate base, however, has not been structurally characterized until now. Presented here is a first crystal structure of a freebase corrole anion, derived from tris(p-cyanophenyl)corrole, as the tetrabuylammonium salt. The low-temperature (100 K) structure reveals ...
    • From Diaminosilylenes to Silapyramidanes: Making Sense of the Stability of Divalent Silicon Compounds 

      Torstensen, Kristian; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-07)
      Since the discovery of decamethylsilicocene over three decades ago, chemists have successfully isolated a variety of divalent silicon compounds by orchestrating steric and electronic effects to their advantage. Two broad strategies of electronic stabilization appear to have been widely deployed, namely, π-conjugation as in diaminosilylenes and π-complexation as in decamethylsilicocene and ...
    • Full Breit Hamiltonian in the Multiwavelets Framework 

      Tantardini, Christian; Remigio, Roberto Di; Bjørgve, Magnar; Jensen, Stig Rune; Frediani, Luca (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-01-01)
      New techniques in core–electron spectroscopy are necessary to resolve the structures of oxides of f-elements and other strongly correlated materials that are present only as powders and not as single crystals. Thus, accurate quantum chemical methods must be developed to calculate core spectroscopic properties in such materials. In this contribution, we present an important development in this ...
    • Fully Polarizable QM/Fluctuating Charge Approach to Two-Photon Absorption of Aqueous Solutions 

      Di Remigio, Roberto; Giovannini, Tommaso; Ambrosetti, Matteo; Cappelli, Chiara; Frediani, Luca (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-06-05)
      We present the extension of the quantum/classical polarizable fluctuating charge model to the calculation of single residues of quadratic response functions, as required for the computational modeling of two-photon absorption cross sections. By virtue of a variational formulation of the quantum/classical polarizable coupling, we are able to exploit an atomic orbital-based quasienergy formalism to ...
    • Full‐length 16S rRNA gene classification of Atlantic salmon bacteria and effects of using different 16S variable regions on community structure analysis 

      Klemetsen, Terje; Willassen, Nils Peder; Karlsen, Christian René (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-07-04)
      Understanding fish‐microbial relationships may be of great value for fish producers as fish growth, development and welfare are influenced by the microbial community associated with the rearing systems and fish surfaces. Accurate methods to generate and analyze these microbial communities would be an important tool to help improve understanding of microbial effects in the industry. In this study, ...
    • 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 ...