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- Trygve Helgaker

Chemistry

Norway

2022

Discipline name
D-index
D-index (Discipline H-index) only includes papers and citation values for an examined
discipline in contrast to General H-index which accounts for publications across all
disciplines.
Citations
Publications
World Ranking
National Ranking

Chemistry
D-index
87
Citations
27,048
267
World Ranking
985
National Ranking
1

2022 - Research.com Chemistry in Norway Leader Award

2007 - Centenary Prize, Royal Society of Chemistry (UK)

- Quantum mechanics
- Electron
- Molecule

Trygve Helgaker mainly investigates Atomic physics, Basis set, Computational chemistry, Wave function and Quantum mechanics. He has included themes like Ab initio quantum chemistry methods, Atomic orbital, Electronic structure, Coupled cluster and Density functional theory in his Atomic physics study. His studies in Basis set integrate themes in fields like Basis, Extrapolation and Perturbation theory.

His Computational chemistry research incorporates themes from Hessian matrix, Spin, Molecular physics, Simple and Ab initio. His research in Wave function intersects with topics in Function, Configuration interaction and Condensed matter physics. His research in Quantum mechanics is mostly concerned with Hamiltonian.

- Basis-set convergence of correlated calculations on water (1653 citations)
- Basis-set convergence in correlated calculations on Ne, N2, and H2O (1553 citations)
- Molecular Electronic-Structure Theory: Helgaker/Molecular Electronic-Structure Theory (1303 citations)

Trygve Helgaker spends much of his time researching Atomic physics, Quantum mechanics, Computational chemistry, Wave function and Density functional theory. His Atomic physics study incorporates themes from Field, Atomic orbital, Ab initio and Molecule, Basis set. His study in Atomic orbital is interdisciplinary in nature, drawing from both Coupled cluster and Tensor.

His studies examine the connections between Basis set and genetics, as well as such issues in Basis, with regards to Limit. His biological study deals with issues like Coupling constant, which deal with fields such as Electromagnetic shielding and Nuclear magnetic resonance. His studies deal with areas such as Electronic correlation, Dipole, Classical mechanics, Configuration interaction and Electronic structure as well as Wave function.

- Atomic physics (31.91%)
- Quantum mechanics (23.87%)
- Computational chemistry (21.86%)

- Density functional theory (23.12%)
- Magnetic field (11.81%)
- Quantum mechanics (23.87%)

Trygve Helgaker focuses on Density functional theory, Magnetic field, Quantum mechanics, Atomic physics and Molecule. His Density functional theory research includes themes of Wave function, Regular polygon, Statistical physics, Analytical chemistry and Electron density. His Magnetic field research integrates issues from Current density, Paramagnetism, Condensed matter physics and Atomic orbital.

His research in Quantum mechanics tackles topics such as Quantum electrodynamics which are related to areas like Perturbation theory. The Atomic physics study combines topics in areas such as Adiabatic process, Bond length, Excitation and Atoms in molecules. The concepts of his Molecule study are interwoven with issues in Bound state, Molecular physics, Excited state, Diamagnetism and Hamiltonian.

- The Dalton quantum chemistry program system (782 citations)
- Analytic cubic and quartic force fields using density-functional theory (30 citations)
- Non-perturbative calculation of molecular magnetic properties within current-density functional theory. (29 citations)

- Quantum mechanics
- Electron
- Molecule

Trygve Helgaker mainly focuses on Density functional theory, Magnetic field, Atomic physics, Quantum mechanics and Molecule. His Density functional theory research is mostly focused on the topic Basis set. In his study, which falls under the umbrella issue of Basis set, Hartree–Fock method is strongly linked to Ion.

His biological study spans a wide range of topics, including Bond length, Coulomb, Atoms in molecules, Physical system and Adiabatic process. In the subject of general Quantum mechanics, his work in Ab initio quantum chemistry methods, Molecular electronic structure, Fock matrix and Complete active space is often linked to Quantum chemistry, thereby combining diverse domains of study. Trygve Helgaker combines subjects such as Diamagnetism, Chemical physics and Molecular dynamics with his study of Molecule.

This overview was generated by a machine learning system which analysed the scientist’s body of work. If you have any feedback, you can contact us here.

Basis-set convergence of correlated calculations on water

Trygve Helgaker;Wim Klopper;Henrik Koch;Jozef Noga.

Journal of Chemical Physics **(1997)**

2199 Citations

Molecular Electronic-Structure Theory: Helgaker/Molecular Electronic-Structure Theory

Trygve Helgaker;Poul Jørgensen;Jeppe Olsen.

**(2000)**

2115 Citations

Basis-set convergence in correlated calculations on Ne, N2, and H2O

Asger Halkier;Trygve Helgaker;Poul Jørgensen;Wim Klopper.

Chemical Physics Letters **(1998)**

2039 Citations

Ab Initio Methods for the Calculation of NMR Shielding and Indirect Spin-Spin Coupling Constants

Trygve Helgaker;Michał Jaszuński;Kenneth Ruud.

Chemical Reviews **(1999)**

1515 Citations

Excitation energies in density functional theory : an evaluation and a diagnostic test.

Michael J. G. Peach;Peter Benfield;Trygve Helgaker;David J. Tozer.

Journal of Chemical Physics **(2008)**

1194 Citations

The Dalton quantum chemistry program system

Kestutis Aidas;Celestino Angeli;Keld L. Bak;Vebjørn Bakken.

Wiley Interdisciplinary Reviews: Computational Molecular Science **(2014)**

960 Citations

Basis-set convergence of the energy in molecular Hartree–Fock calculations

Asger Halkier;Trygve Helgaker;Poul Jørgensen;Wim Klopper.

Chemical Physics Letters **(1999)**

632 Citations

Excitation energies from the coupled cluster singles and doubles linear response function (CCSDLR). Applications to Be, CH+, CO, and H2O

Henrik Koch;Hans Jo;rgen Aa. Jensen;Poul Jo.

Journal of Chemical Physics **(1990)**

576 Citations

Dalton, a molecular electronic structure program

H. Agren;David John. Wilson;O. Vahtras;P. R. Taylor.

**(2005)**

556 Citations

Recent Advances in Wave Function-Based Methods of Molecular-Property Calculations

Trygve Helgaker;Sonia Coriani;Poul Jørgensen;Kasper Kristensen.

Chemical Reviews **(2012)**

499 Citations

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