Erik Tellgren

Image of Erik Tellgren
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Room V218
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Visiting address Sem Sælandsvei 26 Kjemibygningen 0371 OSLO
Postal address Postboks 1033 Blindern 0315 OSLO
Other affiliations Department of Chemistry

I am a researcher at CTCC. I have contributed to two quantum chemistry packages (DALTON and DIRAC), and am the main author of a third program (LONDON). LONDON was written from scratch and is a unique quantum-chemical tool to explore the effect of magnetic fields on molecules. Recently, I was awarded a research grant from the Norwegian Research Council to study molecular spin frustration due to relativistic effects and non-uniform magnetic fields.

My other research interests include:

  • Molecules in strong magnetic fields: Quantum chemical work has almost exclusively focused on weak magnetic fields, the effect of which can be modelled as slight perturbations to molecules. By directly modelling the magnetic field effects without recourse to perturbation theory, my research has resulted in novel computational techniques with different strengths and weaknesses. A strength is the ability to explore the exotic physics and chemistry of molecules subject to magnetic field strengths several stronger than what can be produced in a laboratory.
  • Development of Current-Density Functional Theory (CDFT): The most well-known form of Density Functional Theory is only valid in the absence of external magnetic fields. When magnetic vector potentials are placed on an equal footing with scalar potentials, one should also place the current density on an equal footing with the density. The resulting framework, CDFT, is much less developed in terms of practical approximations than DFT, and it remains an interesting challenge to incorporate current-dependence in practical functionals.
  • Formal aspects of DFT/CDFT: My research has helped understand some mathematical aspects of CDFT, such as the extension of Lieb's formulation of DFT to CDFT, the characterization of the class of current densities that can arise from valid quantum mechanical states (a version of the N-representability problem), the status of the Hohenberg-Kohn-like results in CDFT, etc.
  • Linear-scaling methods and PBC: Techniques for reducing the computational cost of SCF calculations on large systems as well as Periodic Boundary Conditions formulated using localized basis functions were among my first research projects. These themes have been not been the primary focus of recent research, but remain among my long-term interests.
Tags: Chemistry, Theoretical chemistry

Publications

  • Adamowicz, Ludwik; Tellgren, Erik & Helgaker, Trygve (2015). Non-Born-Oppenheimer calculations of the HD molecule in a strong magnetic field. Chemical Physics Letters.  ISSN 0009-2614.  639, s 295- 299 . doi: 10.1016/j.cplett.2015.09.051
  • 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
  • Stopkowicz, Stella; Gauss, Jürgen; Lange, Kai Kaarvann; Tellgren, Erik & Helgaker, Trygve (2015). Coupled-cluster theory for atoms and molecules in strong magnetic fields. Journal of Chemical Physics.  ISSN 0021-9606.  143:074110(7) . doi: 10.1063/1.4928056
  • 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
  • Tellgren, Erik; Kvaal, Simen & Helgaker, Trygve (2014). Fermion N -representability for prescribed density and paramagnetic current density. Physical Review A. Atomic, Molecular, and Optical Physics.  ISSN 1050-2947.  89(1) . doi: 10.1103/PhysRevA.89.012515 Full text in Research Archive.
  • 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
  • Tellgren, Erik & Fliegl, Heike (2013). Non-perturbative treatment of molecules in linear magnetic fields: Calculation of anapole susceptibilities. Journal of Chemical Physics.  ISSN 0021-9606.  139(16) . doi: 10.1063/1.4826578
  • Kaarvann, Lange Kai; Tellgren, Erik; Hoffmann, Mark & Helgaker, Trygve (2012). A Paramagnetic Bonding Mechanism for Diatomics in Strong Magnetic Fields. Science.  ISSN 0036-8075.  337(6092), s 327- 331 . doi: 10.1126/science.1219703
  • 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.
  • Tellgren, Erik; Reine, Simen Sommerfelt & Helgaker, Trygve (2012). Analytical GIAO and hybrid-basis integral derivatives: application to geometry optimization of molecules in strong magnetic fields. Physical Chemistry, Chemical Physics - PCCP.  ISSN 1463-9076.  14(26), s 9492- 9499 . doi: 10.1039/c2cp40965h
  • Tellgren, Erik; Helgaker, Trygve & Soncini, Alessandro (2009). Non-perturbative magnetic phenomena in closed-shell paramagnetic molecules. Physical Chemistry, Chemical Physics - PCCP.  ISSN 1463-9076.  11(26), s 5489- 5498 . doi: 10.1039/b822262b
  • Reine, Simen Sommerfelt; Tellgren, Erik; Krapp, Andreas; Kjærgaard, Thomas; Helgaker, Trygve; Jansik, Branislav; Høst, Stinne & Salek, Pawel (2008). Variational and robust density fitting of four-center two-electron integrals in local metrics. Journal of Chemical Physics.  ISSN 0021-9606.  129(10) . doi: 10.1063/1.2956507 Show summary
  • Tellgren, Erik I; Soncini, Alessandro & Helgaker, Trygve (2008). Nonperturbative ab initio calculations in strong magnetic fields using London orbitals. Journal of Chemical Physics.  ISSN 0021-9606.  129, s 154114-1- 154114-9
  • Salek, Pawel; Høst, Stinne; Thøgersen, Lea; Jørgensen, Poul; Manninen, Pekka; Olsen, Jeppe; Jansik, Branislav; Reine, Simen Sommerfelt; Pawlowski, Filip Ludwik; Tellgren, Erik; Helgaker, Trygve & Coriani, Sonia (2007). Linear-scaling implementation of molecular electronic self-consistent field theory. Journal of Chemical Physics.  ISSN 0021-9606.  126
  • Peach, Michael J. G.; Tellgren, Erik; Salek, Pawel; Helgaker, Trygve & Tozer, David J. (2007). Structural and Electronic Properties of Polyacetylene and Polyyne from Hybrid and Coulomb-Attenuated Density Functionals. Journal of Physical Chemistry A.  ISSN 1089-5639.  111, s 11930- 11935 . doi: 10.1021/jp0754839
  • Reine, Simen Sommerfelt; Tellgren, Erik & Helgaker, Trygve (2007). A unified scheme for the calculation of differentiated and undifferentiated molecular integrals over solid-harmonic Gaussians. Physical Chemistry, Chemical Physics - PCCP.  ISSN 1463-9076.  9, s 4771- 4779 . doi: 10.1039/b705594c
  • Tellgren, Erik; Henriksson, J & Norman, P (2007). First-order excited state properties in the four-component Hartree-Fock approximation: The excited state electric dipole moments in CsAg and CsAu. Journal of Chemical Physics.  ISSN 0021-9606.  126

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  • 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.
  • 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; Hoffmann, Mark; Lange, Kai Kaarvann; Soncini, Alessandro & Tellgren, Erik (2014). Molecules in Strong Magnetic Fields.
  • 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; 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.
  • Helgaker, Trygve; Kaarvann, Lange Kai & Tellgren, Erik (2011). Molecules in strong magnetic fields. META.  ISSN 1890-2987.  (3), s 16- 18
  • Tellgren, Erik; Helgaker, Trygve; Ruud, Kenneth & Soncini, Alessandro (2009). Quantum-chemical method development for extended and magnetic systems.
  • Tellgren, Erik & Helgaker, Trygve (2006). Introducing periodic boundary conditions into a molecular code.
  • Tellgren, Erik (2006). Desity-Fitting for the Coulomb interaction in periodic systems.
  • Tellgren, Erik (2006). Implementation of Periodic Boundary Conditions in DALTON.
  • Tellgren, Erik (2006). Implementation of Periodic Boundary Conditions in DALTON.
  • Tellgren, Erik & Helgaker, Trygve (2006). Introducing periodic boundary conditions into a molecular code.

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Published Nov. 11, 2010 9:00 AM - Last modified Mar. 10, 2017 9:25 AM