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Trygve Ulf Helgaker

Image of Trygve Ulf Helgaker
Norwegian
Email t.u.helgaker@kjemi.uio.no
Phone +47-22855428
Fax +47-22855441
Room V236
Username
Visiting address Kjemibygningen Sem Sælandsvei 26 0371 OSLO
Postal address Postboks 1033 Blindern 0315 OSLO

Research

Trygve Helgaker works in the area of molecular electronic-structure theory—in particular, wit the development and application of methods for quantum-mechanical simulations of molecular systems. With the emergence of powerful computers and the development of sophisticat simulation models and techniques, quantum-chemical simulations have become an indispensable too to modern chemical research. Such simulations can be performed either as a supplement to experimental work (e.g., for interpretation of experimental data) or as a replacement of experimental investigations (when these cannot be performed or are too expensive).

Even though modern quantum-chemical methods are nowadays successfully applied to a vast range of problems in research and industry, it still many restrictions with respect to applicability and accuracy. Helgaker's research is directed towards the development of efficient computational methods for large molecular systems, containing hundreds or thousands of atoms such as those encountered in biological systems. Helgaker is also working towards the development of more accurate and flexible quantum-chemical methods, to make studies on large systems as accurate as those on small and medium-sized systems.

Since the 1980s, Trygve Helgaker has developed the quantum-chemistry program system Dalton in cooperation with other researchers in Scandinavia. Dalton has been licensed to almost 2000 research groups worldwide and is one the most flexible program systems in quantum chemistry.

For popular accounts of quantum chemistry, see an article in Apollon and a lecture on quantum chemistry.

Background

Trygve Helgaker (f. 1953) received the degree of cand. scient. in chemistry in 1980 and the degree of dr. philos. in 1986, both at the University of Oslo. After postdoctoral positions at the Institute for Mathematics and its Applications (IMA), University of Minnesota in 1986–87 and at the Department of Chemistry, Aarhus University in 1987–89, Helgaker became an associate professor (førsteamanuensis) at the Department of Chemsitry, University of Oslo in 1989, where he became a full professor in 1993.

Helgaker was on sabbatical leave in the group of Prof. Nicholas Handy at the University of Cambridge in 1999–2000 and in the group of Prof. David Tozer at Durham University in 2006–07. In January 2003, Helgaker a was a guest professor at Faculté de Chimie, Université Louis Pasteur in Strasbourg. Since 2007, Helgaker has been co-director of the  Centre for Theoretical and Computational Chemistry (CTCC), a Centre of Excellence shared with the University of Tromsø 2007–2017.

Helgaker studied Russian at University of Leningrad in 1974–75 and worked as an assistant for Prof. Geir Kjetsaa at the Department of Slavic and Baltic Studies, University of Oslo in1979 (6 months), on the project Written by Dostoevsky?

Publications

Helgaker has published 265 ISI-registered articles, which have been cited more than 14000 times. He is Norway's most cited chemist and has an H-index of 61. His publication list and all publications can be downloaded here.

With Poul Jørgensen and Jeppe Olsen from the Department of Chemistry, Aarhus University, Helgaker has published a 1000-page monograph Molecular Electronic-Structure Theory (Wiley, Chichster, 2000), which has been cited more than 900 times.

Helgaker has translated Russian fiction to Norwegian: Leo Tolstoy, Om vold og kjærlighet (Solum, Oslo, 1977) and Boris Pilnyak, Armesjefens død, in Moderne russiske fortellere, ed. G. Kjetsaa (Aschehoug, Oslo, 1977).

Lectures

Helgaker has given 81 lectures at international meetings and conferences, 49 guest lectures at departments and research institutions, and 236 lectures at international summer and winter schools in quantum chemistry. Many of his lectures can be downloaded here, which also contains a full list of all lectures.

Awards and honours

Meetings and workshops organized

  • Scandinavian Minisymposium on Theoretical Chemistry, 
    Oslo, Norway, September 1983
  • The Nordic Molecular Physics Symposium, Oslo, Norway, May 1986
  • Dalton 2000 Workshop, Oslo Norway, December 5–7, 1998
  • 70 Years of the Correlation Problem, Oslo, Norway, June 3–5,1999
  • Quantum Chemistry SUP Meeting, Oslo, Norway, November 9–11, 2004
  • Nanoquant Meeting, Leangkollen, Norway, February 9–12, 2006
  • A Coastal Voyage of Current Density Functional Theory, 
    Tromsø–Trondheim, September 19–22, 2007
  • Molecular Properties 2009, Vettre, Norway, June 18–21, 2009
  • Dalton 2010 Workshop, Oslo, Norway, January 11–12, 2010
  • Quantum Chemistry Beyond the Article Circle, 
    Sommarøy, Norway, June 23–26, 2010
  • Quantum Chemistry in Strong Magnetic Fields, 
    Toulouse, France, September 13–14, 2010
  • 15th European Seminar on Computational Methods in Quantum Chemistry, 
    Oscarsborg, Norway, June 16–19, 2011

Teaching

Trygve Helgaker teaches the course KJM2600 – Quantum chemistry and spectroscopy at the Department of Chemistry; slides for 2012 are available  here.

Sostrup Summer School: Quantum Chemistry and Molecular Properties

Together with Poul Jørgensen and Jeppe Olsen at Aarhus University, Helgaker has biennially since 1990 organized the Sostrup Summer School: Quantum Chemistry and Molecular Properties, see invitation from 2010 and information about previous summer schools here. Many of his lectures can be downloaded here. Textbook for the summer school is Molecular Electronic-Structure Theory (Wiley, Chichester, 2000), written by Helgaker, Jørgensen and Olsen.

European Summer School in Quantum Chemistry (ESQC)

Since 1991, Helgaker has been a lecturer at the European Summer School in Quantum Chemistry (ESQC),  held biennially near Palermo in Sicily. For his talks given at ESQC, see here.

Boards

Cooperation

  • Sonia Coriani, Universita’ di Trieste, Italy and the Department of Chemistry, University of Oslo
  • Jürgen Gauss, Johannes Gutenberg Universität Mainz, Germany
  • Nicholas Handy, University of Cambridge, UK
  • Mark Hoffmann, University of North Dakota, USA
  • Michal Jaszunski, Polish Academy of Sciences, Warsaw, Poland
  • Hans-Jørgen Aagaard Jensen, University of Southern Denmark, Denmark
  • Poul Jørgensen, Aarhus University, Denmark
  • Henrik Koch, NTNU, Trondheim, Norway
  • Wim Klopper, Karlsruher Institut für Technologie, Germany
  • Claus Jørgen Nielsen, University of Oslo, Norway
  • Jeppe Olsen, Aarhus University, Denmark
  • Magdalena Pecul-Kudelska, Uniwersytet Waszawski, Poland
  • Antonio Rizzo, IPFC CNR, Pisa, Italy
  • Kenneth Ruud, University of Tromsø, Norway
  • Trond Saue, Université Paule Sabatier, Toulouse, France
  • Peter Taylor, University of Melbourne, Australia
  • David Tozer, University of Durham, UK
  • Einar Uggerud, University of Oslo, Norway
  • Hans Ågren, KTH, Stockholm, Sweden

Projects

  • Centre for Theoretical and Computational Chemistry (CTCC),
    a CoE shared with the University of Tromsø, RCN, 2007–2017
  • Molecules in magnetic fields (MAGMOL), FRIPRO, RCN, 2010–2013
  • Ab-initio adiabatic-connection curves for density-functional analysis and construction (ABACUS), ERC Advanced Grant, ERC, 2011–2016

CV

Curriculum vitae can be dowloaded here.

 

Publications

All publications can be downloaded here.

  • Rybkin, Vladimir; Simakov, Anton; Bakken, Vebjørn; Reine, Simen Sommerfelt; Kjærgaard, Thomas; Helgaker, Trygve & Uggerud, Einar (2013). Insights into the dynamics of evaporation and proton migration in protonated water clusters from large-scale bornoppenheimer direct dynamics. Journal of Computational Chemistry.  ISSN 0192-8651.  34(7), s 533- 544 . doi: 10.1002/jcc.23162
  • Teale, Andrew Michael; Lutnæs, Ola Berg; Helgaker, Trygve; Tozer, David J. & Gauss, Jürgen (2013). Benchmarking density-functional theory calculations of NMR shielding constants and spin-rotation constants using accurate coupled-cluster calculations. Journal of Chemical Physics.  ISSN 0021-9606.  138(2) . doi: 10.1063/1.4773016
  • Helgaker, Trygve; Coriani, Sonia; Jørgensen, Poul; Kristensen, Kasper; Olsen, Jeppe & Ruud, Kenneth (2012). Recent Advances in Wave Function-Based Methods of Molecular-Property Calculations. Chemical Reviews.  ISSN 0009-2665.  112(1), s 543- 631 . doi: 10.1021/cr2002239
  • Helgaker, Trygve; Jaszunski, Michal; Garbacz, Piotr & Jackowski, Karol (2012). The NMR indirect nuclear spin-spin coupling constant of the HD molecule. Molecular Physics.  ISSN 0026-8976.  110(19-20), s 2611- 2617 . doi: 10.1080/00268976.2012.729097
  • 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
  • Middendorf, Nils; Höfener, Sebastian; Klopper, Wim & Helgaker, Trygve (2012). Calculation of the two-electron Darwin term using explicitly correlated wave functions. Chemical Physics.  ISSN 0301-0104.  401, s 146- 151 . doi: 10.1016/j.chemphys.2011.10.035
  • Onishi, Taku & Helgaker, Trygve (2012). A Theoretical Study on Hydrogen Transport Mechanism in SrTio(3) Perovskite. International Journal of Quantum Chemistry.  ISSN 0020-7608.  112(1), s 201- 207 . doi: 10.1002/qua.23203
  • Reine, Simen Sommerfelt; Helgaker, Trygve & Lindh, Roland (2012). Multi-electron integrals. Wiley Interdisciplinary Reviews. Computational Molecular Science.  ISSN 1759-0876.  2(2), s 290- 303 . doi: 10.1002/wcms.78
  • Teale, Andrew Michael; Coriani, Sonia & Helgaker, Trygve (2012). Range-dependent adiabatic connections. AIP Conference Proceedings.  ISSN 0094-243X.  1504, s 92- 99 . doi: 10.1063/1.4771706
  • 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
  • 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
  • Bast, Radovan; Ruud, Kenneth; Rizzo, Antonio & Helgaker, Trygve (2011). Relativistic four-component calculations of Buckingham birefringence using London atomic orbitals. Theoretical Chemistry accounts.  ISSN 1432-881X.  129(3-5), s 685- 699 . doi: 10.1007/s00214-011-0939-3
  • Bast, Radovan; Ulf, Ekstrom; Gao, Bin; Helgaker, Trygve; Ruud, Kenneth & Thorvaldsen, Andreas johan (2011). The ab initio calculation of molecular electric, magnetic and geometric properties. Physical Chemistry, Chemical Physics - PCCP.  ISSN 1463-9076.  13(7), s 2627- 2651 . doi: 10.1039/c0cp01647k
  • Iozzi, Maria Francesca; Helgaker, Trygve & Uggerud, Einar (2011). Influence of External Force on Properties and Reactivity of Disulfide Bonds. Journal of Physical Chemistry A.  ISSN 1089-5639.  115(11), s 2308- 2315 . doi: 10.1021/jp109428g
  • Klopper, Wim; Teale, Andrew Michael; Coriani, Sonia; Pedersen, Thomas Bondo & Helgaker, Trygve (2011). Spin flipping in ring-coupled-cluster-doubles theory. Chemical Physics Letters.  ISSN 0009-2614.  510(1-3), s 147- 153 . doi: 10.1016/j.cplett.2011.04.101
  • Strømsheim, Marie Døvre; Kumar, Neena Theresa; Coriani, Sonia; Sagvolden, Espen; Teale, Andrew Michael & Helgaker, Trygve (2011). Dispersion interactions in density-functional theory: An adiabatic-connection analysis. Journal of Chemical Physics.  ISSN 0021-9606.  135(19) . doi: 10.1063/1.3660357
  • Lutnæs, Ola Berg; Helgaker, Trygve & Jaszunski, Michal (2010). Spin-spin coupling constants and triplet instabilities in Kohn-Sham theory. Molecular Physics.  ISSN 0026-8976.  108(19-20), s 2579- 2590 . doi: 10.1080/00268976.2010.513344
  • Reine, Simen Sommerfelt; Krapp, Andreas; Iozzi, Maria Francesca; Bakken, Vebjørn; Helgaker, Trygve; Pawlowski, Filip & Salek, Pawel (2010). An efficient density-functional-theory force evaluation for large molecular systems. Journal of Chemical Physics.  ISSN 0021-9606.  133(4) . doi: 10.1063/1.3459061
  • Teale, Andrew Michael; Coriani, Sonia & Helgaker, Trygve (2010). Accurate calculation and modeling of the adiabatic connection in density functional theory. Journal of Chemical Physics.  ISSN 0021-9606.  132(16) . doi: 10.1063/1.3380834
  • Teale, Andrew Michael; Coriani, Sonia & Helgaker, Trygve (2010). Range-dependent adiabatic connections. Journal of Chemical Physics.  ISSN 0021-9606.  133(16) . doi: 10.1063/1.3488100
  • Friedrich, Joachim; Coriani, Sonia; Helgaker, Trygve & Dolg, Michael (2009). Implementation of the incremental scheme for one-electron first-order properties in coupled-cluster theory. Journal of Chemical Physics.  ISSN 0021-9606.  131(15) . doi: 10.1063/1.3243864
  • Hofener, S; Tew, DP; Klopper, W & Helgaker, Trygve (2009). The geminal basis in explicitly correlated wave functions. Chemical Physics.  ISSN 0301-0104.  356(1-3), s 25- 30 . doi: 10.1016/j.chemphys.2008.10.022
  • Iozzi, Maria Francesca; Helgaker, Trygve & Uggerud, Einar (2009). Assessment of theoretical methods for the determination of the mechanochemical strength of covalent bonds. Molecular Physics.  ISSN 0026-8976.  107(23-24), s 2537- 2546 . doi: 10.1080/00268970903401041
  • Jansik, B; Host, S; Johansson, MP; Olsen, J; Jorgensen, P & Helgaker, Trygve (2009). A stepwise atomic, valence-molecular, and full-molecular optimisation of the Hartree-Fock/Kohn-Sham energy. Physical Chemistry, Chemical Physics - PCCP.  ISSN 1463-9076.  11(27), s 5805- 5813 . doi: 10.1039/b901987a
  • Jansik, Branislav; Høst, Stinne; Johansson, M. P.; Olsen, Jeppe; Jørgensen, Poul & Helgaker, Trygve (2009). Robust and Reliable Multilevel Minimization of the Kohn-Sham Energy. Journal of Chemical Theory and Computation.  ISSN 1549-9618.  5(4), s 1027- 1032 . doi: 10.1021/ct800562h
  • Lutnæs, Ola B.; Teale, AM; Helgaker, Trygve; Tozer, DJ; Ruud, Kenneth & Gauss, J (2009). Benchmarking density-functional-theory calculations of rotational g tensors and magnetizabilities using accurate coupled-cluster calculations. Journal of Chemical Physics.  ISSN 0021-9606.  131(14) . doi: 10.1063/1.3242081

View all works in Cristin

  • Helgaker, Trygve (2012). Basis functions and basis sets.
  • Helgaker, Trygve (2012). Basis functions and basis sets.
  • Helgaker, Trygve (2012). Basis sets for electron correlation.
  • Helgaker, Trygve (2012). Basis sets for electron correlation.
  • Helgaker, Trygve (2012). Chemical bonding in strong magnetic fields.
  • Helgaker, Trygve (2012). Chemical bonding in strong magnetic fields.
  • Helgaker, Trygve (2012). Current-density-functional theory: basic variables and convex conjugation.
  • Helgaker, Trygve (2012). Density-functional theory.
  • Helgaker, Trygve (2012). Density-functional theory in magnetic fields.
  • Helgaker, Trygve (2012). Density-functional theory in magnetic fields.
  • Helgaker, Trygve (2012). Geometry optimization.
  • Helgaker, Trygve (2012). High-accuracy quantum chemistry.
  • Helgaker, Trygve (2012). Kvantekmekanikk på datamaskiner: kjemiens nye verktøy.
  • Helgaker, Trygve (2012). Magnetic resonance parameteres.
  • Helgaker, Trygve (2012). Molecular bonding in strong magnetic fields.
  • Helgaker, Trygve (2012). Molecular integral evaluation.
  • Helgaker, Trygve (2012). Molecular magnetic propeties.
  • Helgaker, Trygve (2012). Molecules in an external magnetic field.
  • Helgaker, Trygve (2012). Molecules in strong magnetic fields.
  • Helgaker, Trygve (2012). Molecules in strong magnetic fields.
  • Helgaker, Trygve (2012). The electronic Hamiltonian.
  • Helgaker, Trygve (2012). The molecular Hamiltonian.
  • Helgaker, Trygve (2012). Time-independent molecular properties.
  • Helgaker, Trygve (2012). Time-independent molecular properties.
  • Helgaker, Trygve (2011). Centre for Theoretical and Computational Chemistry.
  • Helgaker, Trygve (2011). Geometry Optimization.
  • Helgaker, Trygve (2011). Importing ab-initio theory into DFT. some applications of the Lieb variation principle.
  • Helgaker, Trygve (2011). Kvantemekanikk på datamaskiner: kjemiens nye verktøy.
  • Helgaker, Trygve (2011). Kvantemekanikk på datamaskiner: kjemiens nye verktøy.
  • Helgaker, Trygve (2011). Kvantemekanikk på datamaskiner: kjemiens nye verktøy.
  • Helgaker, Trygve (2011). Molecular Electronic-Structure Theory: Yesterday, Today and Tomorrow.
  • Helgaker, Trygve (2011). Molecular Magnetic Properties.
  • Helgaker, Trygve (2011). Molecular bonding in strong magnetic fields.
  • Helgaker, Trygve (2011). Molecular electronic structure in strong magnetic fields.
  • Helgaker, Trygve (2011). Molecular electronic-structure theory; some current trends.
  • Helgaker, Trygve (2011). Molecules in strong magnetic fields.
  • Helgaker, Trygve (2011). Molecules in strong magnetic fields.
  • Helgaker, Trygve (2011). Molecules in strong magnetic fields.
  • Helgaker, Trygve (2011). Molecules in strong magnetic fields.
  • Helgaker, Trygve (2011). Molecules in strong magnetic fields: electron correlation.
  • Helgaker, Trygve (2011). Molecules in strong magnetic fields: electron correlation.
  • Helgaker, Trygve (2011). Quantum chemistry: wave-function and density-functional methods.
  • Helgaker, Trygve (2011). TIme-independent molecular properties.
  • Helgaker, Trygve; Kaarvann, Lange Kai & Tellgren, Erik (2011). Molecules in strong magnetic fields. Meta.  ISSN 1890-1956.  (3), s 16- 18
  • Gisler, Galen Ross; Celledoni, Elena; Helgaker, Trygve; Iversen, Trond; Jakobsen, Kjetill Sigurd; Jones, Colin N.; Lipniacka, Anna; Lundervold, Arvid; Olsen, Nils Reidar Bøe; De Smedt, Koenraad; Koster, Jacko & Høst, Gudmund (2010). The scientific case for eInfrastructure in Norway.
  • Helgaker, Trygve (2010). Ab initio studies for the adiabatic connection in density-functional theory.
  • Helgaker, Trygve (2010). Ab-initio studies of the adiabatic connection in density-functional teory.
  • Helgaker, Trygve (2010). Basis Functions and Basis Sets.
  • Helgaker, Trygve (2010). Basis Sets for Electron Correlation.
  • Helgaker, Trygve (2010). Calculation and Modeling of Adiabatic-Connection Curves.
  • Helgaker, Trygve (2010). Computational Chemistry.
  • Helgaker, Trygve (2010). Convergence properties of the coupled-cluster method: the accurate calculation of molecular properties for light systems.
  • Helgaker, Trygve (2010). Density-functional theory.
  • Helgaker, Trygve (2010). Geometry optimization.
  • Helgaker, Trygve (2010). Molecular Integral Evaluation.
  • Helgaker, Trygve (2010). Molecular Magnetic Properties.
  • Helgaker, Trygve (2010). Molecules in strong magnetic fields.
  • Helgaker, Trygve (2010). Molecules in strong magnetic fields.
  • Helgaker, Trygve (2010). Molecules in strong magnetic fields.
  • Helgaker, Trygve (2010). Molecules in strong magnetic fields.
  • Helgaker, Trygve (2010). Rigorous calculation of the universal density functional by the Lieb variation principle.
  • Helgaker, Trygve (2010). The Molecular Hamiltonian.
  • Helgaker, Trygve (2010). The calculation of the universal density functional by Lieb maximization.
  • Helgaker, Trygve (2010). The exhaustion of the Schrodinger equation: The accurate calculation of molecular properties of light systems.
  • Helgaker, Trygve (2010). The rigorous calculation of the universal density functional by the Lieb variation principle.
  • Helgaker, Trygve (2010). Time-Independent Molecular Properties.
  • Helgaker, Trygve (2009). Computational Chemistry.
  • Helgaker, Trygve (2009). From ab initio methods to density-functional theory.
  • Helgaker, Trygve (2009). Geometry Optimization.
  • Helgaker, Trygve (2009). Linear-Scaling Methods for Molecular Energies and Properties.
  • Helgaker, Trygve (2009). Molecular Magnetic Properties.
  • Helgaker, Trygve (2009). The Adiabatic Connection.
  • Helgaker, Trygve (2009). The Generalized Adiabatic Connection.
  • Helgaker, Trygve (2009). Time-Independent Molecular Properties.

View all works in Cristin

Published Nov 19, 2010 02:36 PM - Last modified May 10, 2013 12:09 PM

Projects

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