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Trygve Ulf Helgaker

Professor - Theoretical chemistry
Image of Trygve Ulf Helgaker
Norwegian version of this page
Phone +47-22855428
Room V236
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Visiting address Sem Sælands vei 26 Kjemibygningen 0371 OSLO
Postal address Postboks 1033 Blindern 0315 OSLO
Other affiliations Department of Chemistry

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 (gas-phase electron diffraction) in 1980 and the degree of dr. philos. (theoretical  chemistry) 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 and a guest professor at Laboratoire de Chimie Théoretique (LCT), Université Pierre et Marie Curie (UPMC) i Paris i november 2013. Helgaker is the 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 288 ISI-registered articles, which have been cited more than 17000 times. He is Norway's most cited chemist and has an H-index of 65. 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 1700 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 83 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

Teaching

Trygve Helgaker has most recently taught 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 organized biennially from 1990 to 2014 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
  • Andreas Savin, Université Pierre et Marie Curie, Paris, France
  • Peter Taylor, University of Melbourne, Australia
  • Andy Teale, University of Nottingham, UK
  • Julien Toulouse, Université Pierre et Marie Curie, Paris, France
  • 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
  • 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.

  • Cheng, Chi Y.; Ryley, Matthew S.; Peach, Michael J. G.; Tozer, David J.; Helgaker, Trygve & Teale, Andrew Michael (2015). Molecular properties in the Tamm–Dancoff approximation: indirect nuclear spin–spin coupling constants. Molecular Physics.  ISSN 0026-8976. . doi: 10.1080/00268976.2015.1024182
  • Hoffmann, Mark R. & Helgaker, Trygve (2015). Use of Density Functional Theory Orbitals in the GVVPT2 Variant of Second-Order Multistate Multireference Perturbation Theory. Journal of Physical Chemistry A.  ISSN 1089-5639.  119, s 1548- 1553 . doi: dx.doi.org/10.1021/jp507554v
  • Rebolini, Elisa; Toulouse, Julien; Teale, Andrew Michael; Helgaker, Trygve & Savin, A (2015). Calculating excitation energies by extrapolation along adiabatic connections. Physical Review A. Atomic, Molecular, and Optical Physics.  ISSN 1050-2947.  91 . doi: 10.1103/PhysRevA.91.032519
  • Rebolini, Elisa; Toulouse, Julien; Teale, Andrew Michael; Helgaker, Trygve & Savin, Andreas (2015). Excited states from a range-separated density-functional perturbation theory. Molecular Physics.  ISSN 0026-8976. . doi: 10.1080/00268976.2015.1011248
  • Ryding, Mauritz Johan Olof; Izsak, Robert; Merlot, Patrick; Reine, Simen Sommerfelt; Helgaker, Trygve & Uggerud, Einar (2015). Geometry of the magic number H+(H2O)21 water cluster by proxy. Physical Chemistry, Chemical Physics - PCCP.  ISSN 1463-9076.  17, s 5466- 5473 . doi: /10.1021/jp507554v
  • 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
  • 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
  • Merlot, Patrick; Izsak, Robert; Borgoo, Alex; Kjærgaard, Thomas; Helgaker, Trygve & Reine, Simen Sommerfelt (2014). Charge-constrained auxiliary-density-matrix methods for the Hartree-Fock exchange contribution. Journal of Chemical Physics.  ISSN 0021-9606.  141(9) . doi: 10.1063/1.4894267
  • Rebolini, Elisa; Toulouse, Julien; Teale, Andrew Michael; Helgaker, Trygve & Savin, Andreas (2014). Excitation energies along a range-separated adiabatic connection. Journal of Chemical Physics.  ISSN 0021-9606.  141(4) . doi: 10.1063/1.4890652
  • Ringholm, Magnus; Jonsson, Dan Johan; Bast, Radovan; Gao, Bin; Thorvaldsen, Andreas johan; Ekstrøm, Ulf; Helgaker, Trygve & Ruud, Kenneth (2014). Analytic cubic and quartic force fields using density-functional theory. Journal of Chemical Physics.  ISSN 0021-9606.  140(3) . doi: 10.1063/1.4861003
  • Smalø, Hans Sverre; Rybkin, Vladimir; Klopper, Wim; Helgaker, Trygve & Uggerud, Einar (2014). Mechanochemistry: The effect of dynamics. Journal of Physical Chemistry A.  ISSN 1089-5639.  118(36), s 7683- 7694
  • 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
  • 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
  • Helgaker, Trygve; Gauss, Jürgen; Gabriele, Cazzoli & Cristina, Puzzarini (2013). 33S hyperfine interactions in H2S and SO2 and revision of the sulfur nuclear magnetic shielding scale. Journal of Chemical Physics.  ISSN 0021-9606.  139(24:244308) . doi: 10.1063/1.4849177
  • Merlot, Patrick; Kjærgaard, Thomas; Helgaker, Trygve; Lindh, Roland; Aquilante, Francesco; Reine, Simen Sommerfelt & Pedersen, Thomas Bondo (2013). Attractive electron-electron interactions within robust local fitting approximations. Journal of Computational Chemistry.  ISSN 0192-8651.  34(17), s 1486- 1496 . doi: 10.1002/jcc.23284
  • Onishi, Taku & Helgaker, Trygve (2013). 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
  • Onishi, Taku & Helgaker, Trygve (2013). A Theoretical Study on Proton Conduction Mechanism in BaZrO3 Perovskite, In Matti Hotokka; Erkki J. Brändas; Jean Maruani & Gerardo Delgado-Barrio (ed.),  Advances in Quantum Methods and Applications in Chemistry, Physics, and Biology.  Springer.  ISBN 978-3-319-01528-6.  14.  s 238 - 248
  • Przybytek, Michal & Helgaker, Trygve (2013). The accuracy of the Gaussian-and-finite-element-Coulomb (GFC) method for the calculation of Coulomb integrals. Journal of Chemical Physics.  ISSN 0021-9606.  139(5) . doi: 10.1063/1.4817002
  • Rekkedal, Johannes Andreas; Coriani, Sonia; Iozzi, Maria Francesca; Teale, Andrew Michael; Helgaker, Trygve & Pedersen, Thomas Bondo (2013). Communication: Analytic gradients in the random-phase approximation. Journal of Chemical Physics.  ISSN 0021-9606.  139(8) . doi: 10.1063/1.4819399
  • Rybkin, Vladimir; Ekstrøm, Ulf & Helgaker, Trygve (2013). Internal-to-Cartesian Back Transformation of Molecular Geometry Steps Using High-Order Geometric Derivatives. Journal of Computational Chemistry.  ISSN 0192-8651.  34, s 1842- 1849
  • 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
  • Stoyanova, Alexandrina; Teale, Andrew Michael; Toulouse, Julien; Helgaker, Trygve & Fromager, Emmanuel (2013). Alternative separation of exchange and correlation energies in multi-configuration range-separated density-functional theory. Journal of Chemical Physics.  ISSN 0021-9606.  139(13) . doi: 10.1063/1.4822135
  • 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

View all works in Cristin

  • Helgaker, Trygve (2015). Density-Functional Theory in Magnetic Fields.
  • Helgaker, Trygve (2015). Density-functional theory in magnetic fields.
  • Helgaker, Trygve (2015). Egil A. Hylleraas.
  • Helgaker, Trygve (2015). Exact but Differentiable Formulation of Density-Functional Theory.
  • Helgaker, Trygve (2015). Exact but Differentiable Formulation of Density-Functional Theory.
  • Helgaker, Trygve (2015). Magnetisk binding.
  • Helgaker, Trygve (2015). Moreau–Yosida Regularised DFT.
  • Helgaker, Trygve & Reine, Simen Sommerfelt (2015, 29. januar). Fremtidens nanomedisiner bygger på kvantekjemi. [Tidsskrift].  Apollon.
  • 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.
  • Borgoo, Alex; Teale, Andrew Michael & Helgaker, Trygve (2014). Ensemble energies: An alternative route to excitation energies.
  • Helgaker, Trygve (2014). Basis Functions and Basis Sets.
  • Helgaker, Trygve (2014). Basis Sets for Electron Correlation.
  • Helgaker, Trygve (2014). Beregningskjemi.
  • Helgaker, Trygve (2014). Density-Functional Theory.
  • Helgaker, Trygve (2014). Moelcular Integral Evaluation.
  • Helgaker, Trygve (2014). Molecular Magnetic Properties.
  • Helgaker, Trygve (2014). Nobelprisen i kjemi 2013 og noe annet....
  • Helgaker, Trygve (2014). Quantum-Chemical Calculations of NMR Parameters.
  • Helgaker, Trygve (2014). The Molecular Hamiltonian.
  • Helgaker, Trygve (2014). Time-Independent Molecular Properties.
  • 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.
  • 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.
  • Pedersen, Thomas Bondo; Rekkedal, Johannes Andreas; Leikanger, Karl R.; Iozzi, Maria Francesca; Coriani, Sonia; Teale, Andrew Michael & Helgaker, Trygve (2014). Molecular Properties in the Random Phase Approximation.
  • Reine, Simen Sommerfelt; Helgaker, Trygve; Merlot, Patrick; Kjærgaard, Thomas; Borgoo, Alex & Izsak, Robert (2014). Charge-constrained auxiliary-density-matrix methods for the Hartree-Fock exchange contribution.
  • Sagvolden, Espen; Tellgren, Erik; Ekström, Ulf Egil & Helgaker, Trygve (2014). Cusp based DFT functionals.
  • Stopkowicz, Stella & Helgaker, Trygve (2014). Coupled-Cluster Theory for Molecules in Strong Magnetic Fields.
  • Teale, Andrew Michael; Furness, James; Tellgren, Erik; Ekström, Ulf Egil & Helgaker, Trygve (2014). Density Functional Theory for Molecules in Magnetic Fields.
  • Borgoo, Alex; Sagvolden, Espen; Teale, Andrew Michael; Knecht, Stefan; Savin, A & Helgaker, Trygve (2013). Adiabatic connection for ensemble energies: \\An alternative route to excitation energies.
  • Borgoo, Alex; Savin, A; Knecht, Stefan; Teale, Andrew Michael; Helgaker, Trygve & Sagvolden, Espen (2013). Adiabatic connection for ensemble energies: \\An alternative route to excitation energies.
  • Ekström, Ulf Egil; Kvaal, Simen; Borgoo, Alex; Helgaker, Trygve; Sagvolden, Espen & Tellgren, Erik (2013). Moreau-Yosida regularization of DFT.
  • Helgaker, Trygve (2013). Density-functional theory, with and without a magnetic field.
  • Helgaker, Trygve (2013). Geometry optimization.
  • Helgaker, Trygve (2013). Metoder i teoretisk og beregningsorientert kjemi / Kvantekjemiske beregninger i moderne kjemisk forskning,.
  • Helgaker, Trygve (2013). Molecular Magnetic Properties.
  • Helgaker, Trygve (2013). Molecular Magnetism and Density-Functional Theory in Magnetic Fields.
  • Helgaker, Trygve (2013). Molecular magnetic properties.
  • Helgaker, Trygve (2013). Molecular magnetism and density-functional theory in magnetic fields.
  • Helgaker, Trygve (2013). Molecular magnetism and density-functional theory in magnetic fields.
  • Helgaker, Trygve (2013). Molecular magnetism and density-functional theory in magnetic fields.
  • Helgaker, Trygve (2013). Molecules in Strong Magnetic Fields.
  • Helgaker, Trygve (2013). Molecules in Strong Magnetic Fields.
  • Helgaker, Trygve (2013). Molecules in strong magnetic fields.
  • Helgaker, Trygve (2013). Nobel Prize 2013.
  • Helgaker, Trygve (2013). TIme-independet molecular properties.
  • Kvaal, Simen; Ekström, Ulf Egil; Tellgren, Erik; Borgoo, Alex; Helgaker, Trygve & Sagvolden, Espen (2013). Moreau-Yosida regularization of DFT.
  • Pedersen, Thomas Bondo; Rekkedal, Johannes Andreas; Iozzi, Maria Francesca; Coriani, Sonia; Teale, Andrew Michael & Helgaker, Trygve (2013). Molecular Properties in the Random Phase Approximation.
  • 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.
  • Stopkowicz, Stella & Helgaker, Trygve (2013). Correlated molecular energies in strong magnetic fields.
  • 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.

View all works in Cristin

Published Nov 19, 2010 02:36 PM - Last modified May 29, 2015 07:07 PM