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Professor Trygve Helgaker

 

Publications

  • Furness, James W.; Ekström, Ulf Egil; Helgaker, Trygve & Teale, Andrew Michael (2016). Electron localisation function in current-density-functional theory. Molecular Physics.  ISSN 0026-8976.  114(7-8), s 1415- 1422 . doi: 10.1080/00268976.2015.1133859
  • Höfener, Sebastian; Trumm, Michael; Koke, Carsten; Heuser, Johannes; Ekström, Ulf Egil; Skerencak-Frech, Andrej; Schimmelpfennig, Bernd & Panak, Petra J. (2016). Computing UV/vis spectra using a combined molecular dynamics and quantum chemistry approach: Bis-triazin-pyridine (BTP) ligands studied in solution. Physical Chemistry, Chemical Physics - PCCP.  ISSN 1463-9076.  18(11), s 7728- 7736 . doi: 10.1039/c5cp07540h
  • Furness, James W.; Verbeke, Joachim; Tellgren, Erik; Stopkowicz, Stella; Ekström, Ulf Egil; Helgaker, Trygve & Teale, Andrew Michael (2015). Current density functional theory using meta-generalized gradient exchange-correlation functionals. Journal of Chemical Theory and Computation.  ISSN 1549-9618.  11(9), s 4169- 4181 . doi: 10.1021/acs.jctc.5b00535
  • Reimann, Sarah; Ekström, Ulf Egil; Stopkowicz, Stella; Teale, Andrew Michael; Borgoo, Alex & Helgaker, Trygve (2015). The importance of current contributions to shielding constants in density-functional theory. Physical Chemistry, Chemical Physics - PCCP.  ISSN 1463-9076.  17(28), s 18834- 18842 . doi: 10.1039/c5cp02682b
  • Aidas, Kestutis; Angeli, Celestino; Bak, Keld L.; Bakken, Vebjørn; Bast, Radovan; Boman, Linus; Christiansen, Ove; Cimiraglia, Renzo; Coriani, Sonja; Dahle, Pål; Dalskov, Erik K.; Ekström, Ulf Egil; Enevoldsen, Thomas; Eriksen, Janus J.; Ettenhuber, Patrick; Fernández, Berta; Ferrighi, Lara; Fliegl, Heike; Frediani, Luca; Hald, Kasper; Halkier, Asger; Hattig, Christof; Heiberg, Hanne; Helgaker, Trygve; Hennum, Alf Christian; Hettema, Hinne; Hjertenæs, Eirik; Høst, Stine; Høyvik, Ida Marie; Iozzi, Maria Francesca; Jansik, Brannislav; Jensen, Hans-Jørgen Aa.; Jonsson, Dan Johan; Jørgensen, Poul; Kauczor, Johanna; Kirpekar, Sheela; Kjærgaard, Thomas; Klopper, Wim; Knecht, Stefan; Kobayashi, Rika; Koch, Henrik; Kongsted, Jacob; Krapp, Andreas; Kristensen, Kasper; Ligabue, Andrea; Lutnæs, Ola B.; Melo, Juan I.; Mikkelsen, Kurt V.; Myhre, Rolf Heilemann; Neiss, Christian; Nielsen, Christian B.; Norman, Patrick; Olsen, Jeppe; Olsen, Jogvan Magnus H.; Osted, Anders; Packer, Martin J.; Pawlowski, Filip; Pedersen, Thomas Bondo; Provasi, Patricio F.; Reine, Simen Sommerfelt; Rinkevicius, Zilvinas; Ruden, Torgeir A.; Ruud, Kenneth; Rybkin, Vladimir V.; Salek, Pawel; Samson, Claire C. M.; Sanchez de Meras, Alfredo; Saue, Trond; Sauer, Stephan P. A.; Schimmelpfennig, Bernd; Sneskov, Kristian; Steindal, Arnfinn Hykkerud; Sylvester-Hvid, Kristian O.; Taylor, Peter R.; Teale, Andrew M.; Tellgren, Erik; Tew, David P.; Thorvaldsen, Andreas J.; Thøgersen, Lea; Vahtras, Olav; Watson, Mark A.; Wilson, David J. D.; Ziolkowski, Marcin & Ågren, Hans (2014). The Dalton quantum chemistry program system. Wiley Interdisciplinary Reviews. Computational Molecular Science.  ISSN 1759-0876.  4(3), s 269- 284 . doi: 10.1002/wcms.1172 Full text in Research Archive. Show summary
  • Kvaal, Simen; Ekström, Ulf Egil; Teale, Andrew Michael & Helgaker, Trygve (2014). Differentiable but exact formulation of density-functional theory. Journal of Chemical Physics.  ISSN 0021-9606.  140(18) . doi: 10.1063/1.4867005
  • Ringholm, Magnus; Bast, Radovan; Oggioni, Luca; Ekström, Ulf Egil & Ruud, Kenneth (2014). Analytic calculations of hyper-Raman spectra from density functional theory hyperpolarizability gradients. Journal of Chemical Physics.  ISSN 0021-9606.  141(13) . doi: 10.1063/1.4896606 Full text in Research Archive.
  • Rybkin, Vladimir & Ekström, Ulf Egil (2014). Sampling microcanonical ensembles of trajectories using harmonic approximation in internal coordinates. Journal of Chemical Physics.  ISSN 0021-9606.  141(6) . doi: 10.1063/1.4892109
  • Tellgren, Erik; Teale, Andrew Michael; Furness, J.W.; Lange, Kai Kaarvann; Ekström, Ulf Egil & Helgaker, Trygve (2014). Non-perturbative calculation of molecular magnetic properties within current-density functional theory. Journal of Chemical Physics.  ISSN 0021-9606.  140(3) . doi: 10.1063/1.4861427
  • Sagvolden, Espen; Ekström, Ulf Egil & Tellgren, Erik (2013). Isoorbital indicators for current density functional theory. Molecular Physics.  ISSN 0026-8976.  111(9-11), s 1295- 1302 . doi: 10.1080/00268976.2013.802383
  • Ruud, Kenneth; Bast, Radovan; Gao, Bin; Thorvaldsen, Andreas johan; Ekström, Ulf Egil & Visscher, Lucas (2012). A General Toolbox for the Calculation of Higher-Order Molecular Properties Using SCF Wave Functions at the One-, Two- and Four-Component Levels of Theory. AIP Conference Proceedings.  ISSN 0094-243X.  1504, s 639- 642 . doi: 10.1063/1.4771776
  • Tellgren, Erik; Kvaal, Simen; Sagvolden, Espen; Ekström, Ulf Egil; Teale, Andrew Michael & Helgaker, Trygve (2012). Choice of basic variables in current-density-functional theory. Physical Review A. Atomic, Molecular, and Optical Physics.  ISSN 1050-2947.  86(6) . doi: 10.1103/PhysRevA.86.062506 Full text in Research Archive.
  • Orlando, R; Bast, Radovan; Ruud, Kenneth; Ekström, Ulf Egil; Ferrabone, M; Kirtman, B & Dovesi, R (2011). The First and Second Static Electronic Hyperpolarizabilities of Zigzag Boron Nitride Nanotubes. An ab Initio Approach through the Coupled Perturbed Kohn-Sham Scheme. Journal of Physical Chemistry A.  ISSN 1089-5639.  115(45), s 12631- 12637 . doi: 10.1021/jp203237m

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  • Ekström, Ulf Egil (2015). Standard functionals are incompatible with high order perturbation theory.
  • Ekström, Ulf Egil (2015). The universal density functional as an eigenvalue optimization problem.
  • Tellgren, Erik; Teale, Andrew Michael; Ekström, Ulf Egil; Kvaal, Simen; Sagvolden, Espen & Helgaker, Trygve (2015). Current density functional theory for molecular systems in strong magnetic fields.
  • Ekström, Ulf Egil (2014). An optimization problem from exact DFT.
  • Helgaker, Trygve; Borgoo, Alex; Ekström, Ulf Egil; Furness, James; Hoffmann, Mark; Kvaal, Simen; Lange, Kai Kaarvann; Reimann, Sarah; Sagvolden, Espen; Stopkowicz, Stella; Tellgren, Erik & Teale, Andrew Michael (2014). Density-Functional Theory in Magnetic Fields.
  • Helgaker, Trygve; Kvaal, Simen; Ekström, Ulf Egil & Teale, Andrew Michael (2014). Differentiable but Exact Formulation of Density-Functional Theory.
  • Helgaker, Trygve; Kvaal, Simen; Ekström, Ulf Egil & Teale, Andy (2014). Differentiable but Exact Formulation of Density-Functional Theory.
  • Helgaker, Trygve; Kvaal, Simen; Teale, Andrew Michael & Ekström, Ulf Egil (2014). Differentiable but Exact Formulation of Density-Functional Theory.
  • Helgaker, Trygve; Kvaal, Simen; Teale, Andrew Michael; Ekström, Ulf Egil; Jørgensen, Poul & Olsen, Jeppe (2014). Differentiable but Exact Formulation of Density-Functional Theory.
  • Sagvolden, Espen; Tellgren, Erik; Ekström, Ulf Egil & Helgaker, Trygve (2014). Cusp based DFT functionals.
  • Teale, Andrew Michael; Furness, James; Tellgren, Erik; Ekström, Ulf Egil & Helgaker, Trygve (2014). Density Functional Theory for Molecules in Magnetic Fields.
  • Ekström, Ulf Egil & Debnarova, Andrea (2013). The state of scientific software in quantum chemistry.
  • Ekström, Ulf Egil; Kvaal, Simen; Borgoo, Alex; Helgaker, Trygve; Sagvolden, Espen & Tellgren, Erik (2013). Moreau-Yosida regularization of DFT.
  • Kvaal, Simen; Ekström, Ulf Egil; Tellgren, Erik; Borgoo, Alex; Helgaker, Trygve & Sagvolden, Espen (2013). Moreau-Yosida regularization of DFT.
  • Sagvolden, Espen; Tellgren, Erik; Kvaal, Simen; Ekström, Ulf Egil; Teale, Andrew Michael & Helgaker, Trygve (2013). Building blocks of Current Density Functional Theory.
  • Sagvolden, Espen; Tellgren, Erik; Kvaal, Simen; Ekström, Ulf Egil; Teale, Andrew Michael & Helgaker, Trygve (2013). Building blocks of Current Density Functional Theory.

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Published Jan. 13, 2012 1:54 PM - Last modified Feb. 8, 2012 2:35 PM