Erik Ingemar Tellgren

Forsker - Hylleraas-senteret
Bilde av Erik Ingemar Tellgren
English version of this page
Rom V218
Brukernavn
Besøksadresse Sem Sælands vei 26 0371 Oslo
Postadresse Postboks 1033 0315 Oslo

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.
Emneord: Kjemi, Teoretisk kjemi

Publikasjoner

  • Culpitt, Tanner Phillip; Peters, Laurens; Tellgren, Erik Ingemar & Helgaker, Trygve (2022). Analytic calculation of the Berry curvature and diagonal Born-Oppenheimer correction for molecular systems in uniform magnetic fields. Journal of Chemical Physics. ISSN 0021-9606. 156(4). doi: 10.1063/5.0079304.
  • Laestadius, Andre; Penz, Markus & Tellgren, Erik Ingemar (2021). Revisiting density-functional theory of the total current density. Journal of Physics: Condensed Matter. ISSN 0953-8984. 33(29). doi: 10.1088/1361-648X/abf784. Fulltekst i vitenarkiv
  • Kvaal, Simen; Laestadius, Andre; Tellgren, Erik Ingemar & Helgaker, Trygve (2021). Lower Semicontinuity of the Universal Functional in Paramagnetic Current-Density Functional Theory. The Journal of Physical Chemistry Letters. ISSN 1948-7185. 12(5), s. 1421–1425. doi: 10.1021/acs.jpclett.0c03422. Fulltekst i vitenarkiv
  • Peters, Laurens; Culpitt, Tanner Phillip; Monzel, Laurenz; Tellgren, Erik Ingemar & Helgaker, Trygve (2021). Ab Initio molecular dynamics with screened Lorentz forces. II. Efficient propagators and rovibrational spectra in strong magnetic fields. Journal of Chemical Physics. ISSN 0021-9606. 155. doi: 10.1063/5.0056235.
  • Culpitt, Tanner Phillip; Peters, Laurens; Tellgren, Erik Ingemar & Helgaker, Trygve (2021). Ab initio molecular dynamics with screened Lorentz forces. I. Calculation and atomic charge interpretation of Berry curvature . Journal of Chemical Physics. ISSN 0021-9606. 155(2). doi: 10.1063/5.0055388. Fulltekst i vitenarkiv
  • Sen, Sangita & Tellgren, Erik (2021). Benchmarking Density Functional Approximations for Diamagnetic and Paramagnetic Molecules in Nonuniform Magnetic Fields. Journal of Chemical Theory and Computation. ISSN 1549-9618. doi: 10.1021/acs.jctc.0c01222. Fulltekst i vitenarkiv
  • Austad, Jon; Borgoo, Alex; Tellgren, Erik & Helgaker, Trygve (2020). Bonding in the helium dimer in strong magnetic fields: The role of spin and angular momentum. Physical Chemistry, Chemical Physics - PCCP. ISSN 1463-9076. 22(41), s. 23502–23521. doi: 10.1039/d0cp03259j.
  • Adamowicz, Ludwik; Stanke, Monika; Tellgren, Erik & Helgaker, Trygve (2020). A quantum-mechanical non-Born–Oppenheimer model of a molecule in a strong magnetic field. Chemical Physics Letters. ISSN 0009-2614. 761, s. 1–7. doi: 10.1016/j.cplett.2020.138041. Fulltekst i vitenarkiv
  • Laestadius, Andre; Tellgren, Erik; Penz, Markus; Ruggenthaler, Michael; Kvaal, Simen & Helgaker, Trygve (2019). Kohn–Sham Theory with Paramagnetic Currents: Compatibility and Functional Differentiability. Journal of Chemical Theory and Computation. ISSN 1549-9618. 15(7), s. 4003–4020. doi: 10.1021/acs.jctc.9b00141.
  • Penz, Markus; Laestadius, Andre; Tellgren, Erik & Ruggenthaler, Michael (2019). Guaranteed Convergence of a Regularized Kohn-Sham Iteration in Finite Dimensions. Physical Review Letters. ISSN 0031-9007. 123(3). doi: 10.1103/PhysRevLett.123.037401. Fulltekst i vitenarkiv
  • Sen, Sangita; Lange, Kai Kaarvann & Tellgren, Erik (2019). Excited States of Molecules in Strong Uniform and Nonuniform Magnetic Fields. Journal of Chemical Theory and Computation. ISSN 1549-9618. 15(7), s. 3974–3990. doi: 10.1021/acs.jctc.9b00103.
  • Reimann, Sarah; Borgoo, Alex; Austad, Jon; Tellgren, Erik; Teale, Andrew Michael & Helgaker, Trygve (2019). Kohn–Sham energy decomposition for molecules in a magnetic field. Molecular Physics. ISSN 0026-8976. 117(1), s. 97–109. doi: 10.1080/00268976.2018.1495849.
  • Adamowicz, Ludwik; Stanke, Monika; Tellgren, Erik & Helgaker, Trygve (2018). A computational quantum-mechanical model of a molecular magnetic trap. Journal of Chemical Physics. ISSN 0021-9606. 149(24), s. 244112-1–244112-11. doi: 10.1063/1.5055767.
  • Laestadius, Andre; Penz, Markus; Tellgren, Erik; Ruggenthaler, Michael; Kvaal, Simen & Helgaker, Trygve (2018). Generalized Kohn-Sham iteration on Banach spaces. Journal of Chemical Physics. ISSN 0021-9606. 149(16), s. 1–9. doi: 10.1063/1.5037790. Fulltekst i vitenarkiv
  • Sen, Sangita & Tellgren, Erik (2018). A local tensor that unifies kinetic energy density and vorticity in density functional theory. Journal of Chemical Physics. ISSN 0021-9606. 149(14), s. 144109-1–144109-10. doi: 10.1063/1.5041931. Fulltekst i vitenarkiv
  • Sen, Sangita & Tellgren, Erik (2018). Non-perturbative calculation of orbital and spin effects in molecules subject to non-uniform magnetic fields. Journal of Chemical Physics. ISSN 0021-9606. 148(18). doi: 10.1063/1.5029431. Fulltekst i vitenarkiv
  • Laestadius, Andre & Tellgren, Erik (2018). Density-wave-function mapping in degenerate current-density-functional theory. Physical Review A. Atomic, Molecular, and Optical Physics (PRA). ISSN 1050-2947. 97(2). doi: 10.1103/PhysRevA.97.022514. Fulltekst i vitenarkiv
  • Tellgren, Erik (2018). Universal lower bounds on the kinetic energy of electronic systems with noncollinear magnetism. Physical Review A. Atomic, Molecular, and Optical Physics (PRA). ISSN 1050-2947. 97(2), s. 022513-1–022513-5. doi: 10.1103/PhysRevA.97.022513.
  • Tellgren, Erik; Laestadius, Andre; Helgaker, Trygve; Kvaal, Simen & Teale, Andrew Michael (2018). Uniform magnetic fields in density-functional theory. Journal of Chemical Physics. ISSN 0021-9606. 148(2), s. 1–19. doi: 10.1063/1.5007300.
  • Tellgren, Erik (2018). Density-functional theory for internal magnetic fields. Physical Review A. Atomic, Molecular, and Optical Physics (PRA). ISSN 1050-2947. 97(1), s. 1–17. doi: 10.1103/PhysRevA.97.012504.
  • Reimann, Sarah; Borgoo, Alex; Tellgren, Erik; Teale, Andrew Michael & Helgaker, Trygve (2017). Magnetic-Field Density-Functional Theory (BDFT): Lessons from the Adiabatic Connection. Journal of Chemical Theory and Computation. ISSN 1549-9618. 13(9), s. 4089–4100. doi: 10.1021/acs.jctc.7b00295. Fulltekst i vitenarkiv
  • Adamowicz, Ludwik; Stanke, Monika; Tellgren, Erik & Helgaker, Trygve (2017). Explicitly-correlated non-born-oppenheimer calculations of the HD molecule in a strong magnetic field. Chemical Physics Letters. ISSN 0009-2614. 682, s. 87–90. doi: 10.1016/j.cplett.2017.06.016.
  • 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 [Vis alle 7 forfattere av denne artikkelen] (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.
  • 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.
  • 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 (PRA). ISSN 1050-2947. 89(1). doi: 10.1103/PhysRevA.89.012515. Fulltekst i vitenarkiv
  • Aidas, Kestutis; Angeli, Celestino; Bak, Keld L.; Bakken, Vebjørn; Bast, Radovan & Boman, Linus [Vis alle 83 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv
  • 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.
  • 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; 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.
  • 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 (PRA). ISSN 1050-2947. 86(6). doi: 10.1103/PhysRevA.86.062506. Fulltekst i vitenarkiv
  • 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.
  • 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.
  • Reine, Simen Sommerfelt; Tellgren, Erik; Krapp, Andreas; Kjærgaard, Thomas; Helgaker, Trygve & Jansik, Branislav [Vis alle 8 forfattere av denne artikkelen] (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.
  • Salek, Pawel; Høst, Stinne; Thøgersen, Lea; Jørgensen, Poul; Manninen, Pekka & Olsen, Jeppe [Vis alle 12 forfattere av denne artikkelen] (2007). Linear-scaling implementation of molecular electronic self-consistent field theory. Journal of Chemical Physics. ISSN 0021-9606. 126.
  • 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.
  • 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.
  • 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.

Se alle arbeider i Cristin

  • Penz, Markus; Laestadius, Andre; Tellgren, Erik; Ruggenthaler, Michael & Lammert, Paul (2020). Erratum: Guaranteed Convergence of a Regularized Kohn-Sham Iteration in Finite Dimensions. Physical Review Letters. ISSN 0031-9007. 125(24). doi: 10.1103/PhysRevLett.125.249902.
  • Tellgren, Erik & Helgaker, Trygve (2020). Strong Magnetic Field-Induced Chemical Bonding.
  • Laestadius, Andre; Penz, Markus; Tellgren, Erik; Ruggenthaler, Michael; Kvaal, Simen & Helgaker, Trygve (2019). Guaranteed convergence of a regularized Kohn-Sham iteration in finite dimensions.
  • Tellgren, Erik; Helgaker, Trygve & Sen, Sangita (2019). Unifying kinetic energy density and current density in density-functional theory.
  • Tellgren, Erik; Helgaker, Trygve & Sen, Sangita (2019). Unifying kinetic energy density and current density in density-functional theory.
  • Tellgren, Erik; Helgaker, Trygve & Sen, Sangita (2019). Unifying kinetic energy density and current density in density-functional theory.
  • Helgaker, Trygve; Borgoo, Alex; Dimitrova, Maria; Gauss, Jurgen; Hampe, Florian & Holzer, Christof [Vis alle 13 forfattere av denne artikkelen] (2018). Diamagnetism and Paramagnetism in Atoms and Molecules.
  • Helgaker, Trygve; Borgoo, Alex; Gauss, Jurgen; Hampe, Florian; Klopper, Wim & Reimann, Sarah [Vis alle 9 forfattere av denne artikkelen] (2018). Closed-Shell Molecular Paramagnetism.
  • Helgaker, Trygve; Borgoo, Alex; Gauss, Jurgen; Hampe, Florian; Klopper, Wim & Reimann, Sarah [Vis alle 9 forfattere av denne artikkelen] (2018). Closed-Shell Molecular Paramagnetism.
  • Helgaker, Trygve; Borgoo, Alex; Gauss, Jurgen; Hampe, Florian; Klopper, Wim & Stopkowicz, Stella [Vis alle 8 forfattere av denne artikkelen] (2018). Closed-Shell Molecular Magnetism.
  • Laestadius, Andre; Penz, Markus; Tellgren, Erik; Ruggenthaler, Michael; Kvaal, Simen & Helgaker, Trygve (2018). Generalized Kohn-Sham iteration on Banach Spaces.
  • Sen, Sangita & Tellgren, Erik (2018). Excited Molecules in Strong Magnetic Fields.
  • Sen, Sangita & Tellgren, Erik (2018). A local tensor that unifies kinetic energy density and vorticity dependent exchange-correlation functionals .
  • Sen, Sangita & Tellgren, Erik (2018). Molecules in Strong Magnetic Fields.
  • Sen, Sangita & Tellgren, Erik (2018). A local tensor that unifies kinetic energy density and vorticity dependent functionals in DFT.
  • Tellgren, Erik (2018). The Hohenberg-Kohn theorem in a Maxwell-Schrödinger setting.
  • Tellgren, Erik (2018). Magnetic fields, convexity and gauge invariance in density functional theory.
  • Tellgren, Erik; Lange, Kai Kaarvann; Sagvolden, Espen; Kvaal, Simen; Austad, Jon & Reimann, Sarah [Vis alle 9 forfattere av denne artikkelen] (2018). Quantum chemistry for strong magnetic fields.
  • Fliegl, Heike; Helgaker, Trygve & Tellgren, Erik (2018). The effect of strong magnetic fields on the ring currents of tetraoxaisophlorin.
  • Sen, Sangita & Tellgren, Erik (2017). Excited Molecules in Strong Magnetic Fields.
  • Tellgren, Erik (2017). Magnetic fields, convexity and gauge invariance in density functional theory.
  • 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.
  • 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.
  • Helgaker, Trygve; Borgoo, Alex; Ekström, Ulf Egil; Furness, James; Hoffmann, Mark & Kvaal, Simen [Vis alle 12 forfattere av denne artikkelen] (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; 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.
  • 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.
  • Helgaker, Trygve; Kaarvann, Lange Kai & Tellgren, Erik (2011). Molecules in strong magnetic fields. META. ISSN 1890-1956. s. 16–18.
  • Tellgren, Erik (2006). Implementation of Periodic Boundary Conditions in DALTON.
  • Tellgren, Erik (2006). Implementation of Periodic Boundary Conditions in DALTON.
  • Tellgren, Erik (2006). Desity-Fitting for the Coulomb interaction in periodic systems.
  • Tellgren, Erik & Helgaker, Trygve (2006). Introducing periodic boundary conditions into a molecular code.
  • Tellgren, Erik & Helgaker, Trygve (2006). Introducing periodic boundary conditions into a molecular code.
  • Austad, Jon; Helgaker, Trygve & Tellgren, Erik (2020). Theoretical Investigations of Molecular Electronic Structure in a Magnetic Field. Faculty of Mathematics and Natural Sciences, University of Oslo. ISSN 1501-7710. 2020(2295). Fulltekst i vitenarkiv
  • Trøyflat, Jostein; Helgaker, Trygve; Tellgren, Erik & Reine, Simen Sommerfelt (2015). Efficient methods for self-consistent field calculation of molecules in finite magnetic fields. Universitetet i Oslo.
  • Tellgren, Erik; Helgaker, Trygve; Ruud, Kenneth & Soncini, Alessandro (2009). Quantum-chemical method development for extended and magnetic systems. Universitetet i Oslo.

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Publisert 9. nov. 2010 14:25 - Sist endret 29. sep. 2020 14:52