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Trygve Helgaker

Trygve Helgaker

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Chemistry
Norway
2026

D-Index & Metrics

Discipline name D-Index World Ranking Current World Ranking National Ranking Current National Ranking Publications Citations
Chemistry 102 1144 1011 1 1 380 42847

Trygve Helgaker publications per year

The chart shows the history of publications by Trygve Helgaker between 1981 and 2025, highlighting the no. of papers published in each year and offering an overview of the publication velocity of this scholar. Trygve Helgaker published across 45 years, from 1981 to 2025, averaging 9.2 papers a year. Output peaked at 22 publications in 2004. 7 of the 416 publications appeared in the last two years.

No. of publications
5 10 15 20
Bar chart. Horizontal axis: year, 1981 to 2025. Vertical axis: number of publications, 0 to 22. Peak 22 publications in 2004. 1981: 1 publication 1982: 2 publications 1983: 0 publications 1984: 2 publications 1985: 0 publications 1986: 6 publications 1987: 2 publications 1988: 8 publications 1989: 3 publications 1990: 3 publications 1991: 4 publications 1992: 13 publications 1993: 10 publications 1994: 14 publications 1995: 13 publications 1996: 13 publications 1997: 18 publications 1998: 17 publications 1999: 14 publications 2000: 15 publications 2001: 7 publications 2002: 12 publications 2003: 13 publications 2004: 22 publications 2005: 14 publications 2006: 9 publications 2007: 10 publications 2008: 17 publications 2009: 8 publications 2010: 6 publications 2011: 6 publications 2012: 9 publications 2013: 11 publications 2014: 21 publications 2015: 14 publications 2016: 7 publications 2017: 5 publications 2018: 6 publications 2019: 7 publications 2020: 14 publications 2021: 8 publications 2022: 20 publications 2023: 5 publications 2024: 4 publications 2025: 3 publications
1981 2025

416 publications in total across all disciplines

View publications per year as a table
Trygve Helgaker: publications per year, 1981 to 2025
Year Publications
1981 1
1982 2
1983 0
1984 2
1985 0
1986 6
1987 2
1988 8
1989 3
1990 3
1991 4
1992 13
1993 10
1994 14
1995 13
1996 13
1997 18
1998 17
1999 14
2000 15
2001 7
2002 12
2003 13
2004 22
2005 14
2006 9
2007 10
2008 17
2009 8
2010 6
2011 6
2012 9
2013 11
2014 21
2015 14
2016 7
2017 5
2018 6
2019 7
2020 14
2021 8
2022 20
2023 5
2024 4
2025 3
Total 416
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Trygve Helgaker publication distribution in Chemistry in 2026

The chart shows the distribution of publications by all Research.com ranked scientists in the field of Chemistry in 2026. The highlighted bar marks where Trygve Helgaker sits on this spectrum.

No. of scientists
250 500 750 1,000 1,250
Bar chart with 63 bars. Horizontal axis: publications, 61–80 to 1,295+. Vertical axis: number of scientists, 0 to 1,350. Most scientists, 1,350, have 161–180 publications. The last bar groups every scientist with 1,295 publications or more. The highlighted bar, 361–380 publications, is where this scientist sits. 61–80 publications: 66 scientists 81–100 publications: 302 scientists 101–120 publications: 623 scientists 121–140 publications: 918 scientists 141–160 publications: 1,218 scientists 161–180 publications: 1,350 scientists 181–200 publications: 1,344 scientists 201–220 publications: 1,281 scientists 221–240 publications: 1,216 scientists 241–260 publications: 1,100 scientists 261–280 publications: 979 scientists 281–300 publications: 939 scientists 301–320 publications: 764 scientists 321–340 publications: 643 scientists 341–360 publications: 628 scientists 361–380 publications: 522 scientists 381–400 publications: 459 scientists 401–420 publications: 397 scientists 421–440 publications: 327 scientists 441–460 publications: 270 scientists 461–480 publications: 265 scientists 481–500 publications: 252 scientists 501–520 publications: 201 scientists 521–540 publications: 185 scientists 541–560 publications: 148 scientists 561–580 publications: 148 scientists 581–600 publications: 132 scientists 601–620 publications: 114 scientists 621–640 publications: 104 scientists 641–660 publications: 91 scientists 661–680 publications: 92 scientists 681–700 publications: 73 scientists 701–720 publications: 57 scientists 721–740 publications: 54 scientists 741–760 publications: 67 scientists 761–780 publications: 45 scientists 781–800 publications: 46 scientists 801–820 publications: 39 scientists 821–840 publications: 32 scientists 841–860 publications: 36 scientists 861–880 publications: 29 scientists 881–900 publications: 26 scientists 901–920 publications: 24 scientists 921–940 publications: 14 scientists 941–960 publications: 23 scientists 961–980 publications: 28 scientists 981–1,000 publications: 15 scientists 1,001–1,020 publications: 29 scientists 1,021–1,040 publications: 12 scientists 1,041–1,060 publications: 19 scientists 1,061–1,080 publications: 12 scientists 1,081–1,100 publications: 6 scientists 1,101–1,120 publications: 8 scientists 1,121–1,140 publications: 12 scientists 1,141–1,160 publications: 5 scientists 1,161–1,180 publications: 6 scientists 1,181–1,200 publications: 14 scientists 1,201–1,220 publications: 7 scientists 1,221–1,240 publications: 2 scientists 1,241–1,260 publications: 6 scientists 1,261–1,280 publications: 4 scientists 1,281–1,294 publications: 6 scientists 1,295+ publications: 100 scientists
61–80 publications 1,295+

This scientist: 380 publications — 77th percentile

77% of scientists in this discipline score the same or lower.

The last bar groups every scientist with 1,295 publications or more.

View publications distribution as a table
Number of Chemistry scientists by publication count, Research.com 2026 ranking edition. Based on 17,934 ranked scientists.
Publications Scientists This scientist
61–80 66
81–100 302
101–120 623
121–140 918
141–160 1,218
161–180 1,350
181–200 1,344
201–220 1,281
221–240 1,216
241–260 1,100
261–280 979
281–300 939
301–320 764
321–340 643
341–360 628
361–380 522 380
381–400 459
401–420 397
421–440 327
441–460 270
461–480 265
481–500 252
501–520 201
521–540 185
541–560 148
561–580 148
581–600 132
601–620 114
621–640 104
641–660 91
661–680 92
681–700 73
701–720 57
721–740 54
741–760 67
761–780 45
781–800 46
801–820 39
821–840 32
841–860 36
861–880 29
881–900 26
901–920 24
921–940 14
941–960 23
961–980 28
981–1,000 15
1,001–1,020 29
1,021–1,040 12
1,041–1,060 19
1,061–1,080 12
1,081–1,100 6
1,101–1,120 8
1,121–1,140 12
1,141–1,160 5
1,161–1,180 6
1,181–1,200 14
1,201–1,220 7
1,221–1,240 2
1,241–1,260 6
1,261–1,280 4
1,281–1,294 6
1,295+ 100
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Trygve Helgaker D-index placement in Chemistry in 2026

The chart shows the D-index (discipline H-index) distribution of Chemistry scientists ranked by Research.com in 2026. The highlighted bar marks where Trygve Helgaker sits on this spectrum.

No. of scientists
250 500 750 1,000
Bar chart with 61 bars. Horizontal axis: D-Index, 40–41 to 159+. Vertical axis: number of scientists, 0 to 1,051. Most scientists, 1,051, have 56–57 D-Index. The last bar groups every scientist with 159 D-Index or more. The highlighted bar, 102–103 D-Index, is where this scientist sits. 40–41 D-Index: 289 scientists 42–43 D-Index: 612 scientists 44–45 D-Index: 808 scientists 46–47 D-Index: 776 scientists 48–49 D-Index: 835 scientists 50–51 D-Index: 861 scientists 52–53 D-Index: 872 scientists 54–55 D-Index: 933 scientists 56–57 D-Index: 1,051 scientists 58–59 D-Index: 930 scientists 60–61 D-Index: 882 scientists 62–63 D-Index: 834 scientists 64–65 D-Index: 731 scientists 66–67 D-Index: 775 scientists 68–69 D-Index: 683 scientists 70–71 D-Index: 646 scientists 72–73 D-Index: 561 scientists 74–75 D-Index: 501 scientists 76–77 D-Index: 437 scientists 78–79 D-Index: 388 scientists 80–81 D-Index: 354 scientists 82–83 D-Index: 292 scientists 84–85 D-Index: 275 scientists 86–87 D-Index: 254 scientists 88–89 D-Index: 235 scientists 90–91 D-Index: 185 scientists 92–93 D-Index: 192 scientists 94–95 D-Index: 155 scientists 96–97 D-Index: 163 scientists 98–99 D-Index: 125 scientists 100–101 D-Index: 105 scientists 102–103 D-Index: 105 scientists 104–105 D-Index: 112 scientists 106–107 D-Index: 88 scientists 108–109 D-Index: 68 scientists 110–111 D-Index: 69 scientists 112–113 D-Index: 65 scientists 114–115 D-Index: 79 scientists 116–117 D-Index: 61 scientists 118–119 D-Index: 44 scientists 120–121 D-Index: 37 scientists 122–123 D-Index: 40 scientists 124–125 D-Index: 33 scientists 126–127 D-Index: 26 scientists 128–129 D-Index: 34 scientists 130–131 D-Index: 35 scientists 132–133 D-Index: 25 scientists 134–135 D-Index: 27 scientists 136–137 D-Index: 17 scientists 138–139 D-Index: 16 scientists 140–141 D-Index: 20 scientists 142–143 D-Index: 20 scientists 144–145 D-Index: 15 scientists 146–147 D-Index: 9 scientists 148–149 D-Index: 9 scientists 150–151 D-Index: 16 scientists 152–153 D-Index: 11 scientists 154–155 D-Index: 9 scientists 156–157 D-Index: 3 scientists 158 D-Index: 3 scientists 159+ D-Index: 98 scientists
40–41 D-Index 159+

This scientist: 102 D-Index — 94th percentile

94% of scientists in this discipline score the same or lower.

The last bar groups every scientist with 159 D-Index or more.

View D-Index distribution as a table
Number of Chemistry scientists by D-index, Research.com 2026 ranking edition. Based on 17,934 ranked scientists.
D-Index Scientists This scientist
40–41 289
42–43 612
44–45 808
46–47 776
48–49 835
50–51 861
52–53 872
54–55 933
56–57 1,051
58–59 930
60–61 882
62–63 834
64–65 731
66–67 775
68–69 683
70–71 646
72–73 561
74–75 501
76–77 437
78–79 388
80–81 354
82–83 292
84–85 275
86–87 254
88–89 235
90–91 185
92–93 192
94–95 155
96–97 163
98–99 125
100–101 105
102–103 105 102
104–105 112
106–107 88
108–109 68
110–111 69
112–113 65
114–115 79
116–117 61
118–119 44
120–121 37
122–123 40
124–125 33
126–127 26
128–129 34
130–131 35
132–133 25
134–135 27
136–137 17
138–139 16
140–141 20
142–143 20
144–145 15
146–147 9
148–149 9
150–151 16
152–153 11
154–155 9
156–157 3
158 3
159+ 98
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Research.com Recognitions

  • 2026 - Research.com Chemistry in Norway Leader Award
  • 2025 - Research.com Chemistry in Norway Leader Award
  • 2022 - Research.com Chemistry in Norway Leader Award
  • 2007 - Centenary Prize, Royal Society of Chemistry (UK)

Overview

Trygve Helgaker is a researcher primarily affiliated with the University of Oslo in Norway. Their academic work spans the field of Physics and Astronomy, with a concentration on Atomic and Molecular Physics, and Optics. Additional subfields include Spectroscopy, Statistical and Nonlinear Physics, Physical and Theoretical Chemistry, and Materials Chemistry.

Their research topics cover a broad range of advanced and specialized areas such as:

  • Advanced Chemical Physics Studies
  • Spectroscopy and Quantum Chemical Studies
  • Quantum, superfluid, helium dynamics
  • Cold Atom Physics and Bose-Einstein Condensates
  • Molecular Spectroscopy and Structure
  • Machine Learning in Materials Science
  • Catalysis and Oxidation Reactions

Trygve Helgaker has published extensively, with a significant number of works appearing in key scientific venues, including:

  • The Journal of Chemical Physics (10 publications)
  • arXiv (Cornell University) (10 publications)
  • Molecular Physics (5 publications)
  • Faraday Discussions (4 publications)
  • Physical Chemistry Chemical Physics (2 publications)

Among notable recent papers are:

  • "DFT exchange: sharing perspectives on the workhorse of quantum chemistry and materials science" (2022), Physical Chemistry Chemical Physics
  • "Dalton Project: A Python platform for molecular- and electronic-structure simulations of complex systems" (2020), The Journal of Chemical Physics
  • "Analyzing Magnetically Induced Currents in Molecular Systems Using Current-Density-Functional Theory" (2020), The Journal of Physical Chemistry A
  • "Atoms and molecules in soft confinement potentials" (2020), Molecular Physics
  • "Analytic calculation of the Berry curvature and diagonal Born-Oppenheimer correction for molecular systems in uniform magnetic fields" (2022), The Journal of Chemical Physics

Trygve Helgaker collaborates frequently with other researchers, including:

  • Erik I. Tellgren (19 joint works)
  • Laurens D. M. Peters (14 joint works)
  • Tanner Culpitt (11 joint works)
  • Andrew M. Teale (9 joint works)
  • Andre Laestadius (6 joint works)

They received the Centenary Prize from the Royal Society of Chemistry (UK) in 2007.

Best Publications

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

    Trygve Helgaker;Poul Jørgensen;Jeppe Olsen

  • Basis-set convergence of correlated calculations on water

    Trygve Helgaker;Wim Klopper;Henrik Koch;Jozef Noga

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

    Asger Halkier;Trygve Helgaker;Poul Jørgensen;Wim Klopper

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

    Trygve Helgaker;Michał Jaszuński;Kenneth Ruud

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

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

  • The Dalton quantum chemistry program system

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

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

    Asger Halkier;Trygve Helgaker;Poul Jørgensen;Wim Klopper

  • Recent advances in wave function-based methods of molecular-property calculations.

    Trygve Helgaker;Sonia Coriani;Poul Jørgensen;Kasper Kristensen

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

    Henrik Koch;Hans Jørgen Aa. Jensen;Poul Jørgensen;Trygve Helgaker

  • Dalton, a molecular electronic structure program

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

  • The CC3 model: An iterative coupled cluster approach including connected triples

    Henrik Koch;Ove Christiansen;Poul Jørgensen;Alfrede M. Sanchez De Merás

  • Assessment of a Coulomb-attenuated exchange-correlation energy functional.

    Michael J. G. Peach;Trygve Helgaker;Paweł Sałek;Thomas W. Keal

  • Basis set convergence of the interaction energy of hydrogen-bonded complexes

    Asger Halkier;Wim Klopper;Trygve Helgaker;Poul Jo

  • Analytical calculation of nuclear magnetic resonance indirect spin–spin coupling constants at the generalized gradient approximation and hybrid levels of density-functional theory

    Trygve Helgaker;Mark Watson;Nicholas C. Handy

  • Density-functional theory of linear and nonlinear time-dependent molecular properties

    Paweł Sałek;Olav Vahtras;Trygve Helgaker;Hans Ågren

  • The prediction of molecular equilibrium structures by the standard electronic wave functions

    Trygve Helgaker;Jürgen Gauss;Poul Jørgensen;Jeppe Olsen

  • The accurate determination of molecular equilibrium structures

    Keld L. Bak;Jürgen Gauss;Poul Jørgensen;Jeppe Olsen

  • An electronic Hamiltonian for origin independent calculations of magnetic properties

    Trygve Helgaker;Poul Jo;rgensen

  • The quantum-chemical calculation of NMR indirect spin-spin coupling constants

    Trygve Helgaker;Michał Jaszuński;Magdalena Pecul

  • Mo/ller–Plesset energy derivatives

    Poul Jo;rgensen;Trygve Helgaker

Frequent Co-Authors

Kenneth Ruud
Kenneth Ruud University of Tromsø - The Arctic University of Norway
Poul Jørgensen
Poul Jørgensen Aarhus University
Jeppe Olsen
Jeppe Olsen Aarhus University
Wim Klopper
Wim Klopper Karlsruhe Institute of Technology
Sonia Coriani
Sonia Coriani Technical University of Denmark
Henrik Koch
Henrik Koch Scuola Normale Superiore di Pisa
Poul Jo
Poul Jo Aarhus University
Hans Ågren
Hans Ågren Uppsala University
Kurt V. Mikkelsen
Kurt V. Mikkelsen University of Copenhagen
Ove Christiansen
Ove Christiansen Aarhus University

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