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Yasushi Koyama

D-Index & Metrics

Chemistry

D-Index
52
Citations
8156
World Ranking
13674
National Ranking
1054

Yasushi Koyama 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 Yasushi Koyama sits on this spectrum.

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 publications 1,295+

This scientist: 263 publications — 53rd percentile

53% of scientists in this discipline score the same or lower.

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

Yasushi Koyama 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 Yasushi Koyama sits on this spectrum.

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 D-Index 159+

This scientist: 52 D-Index — 26th percentile

26% of scientists in this discipline score the same or lower.

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

Overview

Yasushi Koyama is affiliated with Kwansei Gakuin University in Japan and is primarily engaged in research within the fields of Materials Science and Chemistry. Their work has contributed notably to several subfields, including Materials Chemistry, Inorganic Chemistry, Electronic, Optical and Magnetic Materials, Oncology, and Organic Chemistry.

The primary research topics of Yasushi Koyama cover a range of subjects related to crystallography and chemical compound analysis. These include:

  • Crystallization and Solubility Studies
  • X-ray Diffraction in Crystallography
  • Metal complexes synthesis and properties
  • Magnetism in coordination complexes
  • Metal-Catalyzed Oxygenation Mechanisms
  • Crystal structures of chemical compounds
  • Molecular spectroscopy and chirality

Koyama has collaborated extensively with co-authors such as Ryoji Mitsuhashi, Masahiro Mikuriya, Motohiro Tsuboi, Daisuke Yoshioka, and Sayuri Ono, reflecting a diverse network of academic partnerships.

Their recent publications include:

  • "Detailed magnetic analysis and successful deep-neural-network-based conformational prediction for [VO(dmso)5][BPh4]2" (2020), published in RSC Advances
  • "Crystal Structure of S8 Molecule from Thiourea" (2020), published in X-ray Structure Analysis Online
  • "Crystal Structure of 1,3-Bis(3,5-dibromosalicylideneamino)-2-propanol" (2022), published in X-ray Structure Analysis Online
  • "Crystal Structure of a Hydrolyzed Product of the Cobalt(III) Complex with 1-(3,5-Dichlorosalicylideneamino)-3-amino-2-propanol" (2022), published in X-ray Structure Analysis Online
  • "Preparation and Crystal Structure of Sodium Tetraperoxidochromate(V)" (2020), published in X-ray Structure Analysis Online

Koyama's publications often appear in specialized academic venues such as The Cambridge Structural Database and X-ray Structure Analysis Online, with additional contributions in journals like RSC Advances and the Journal of the Japanese Society of Revegetation Technology. The volume of publications reflects consistent research activity in these areas.

Best Publications

  • Singlet Excited States and the Light‐Harvesting Function of Carotenoids in Bacterial Photosynthesis

    Yasushi Koyama;Michitaka Kuki;Per Ola Andersson;Tomas Gillbro

  • Efficient light harvesting through carotenoids.

    Thorsten Ritz;Ana Damjanović;Klaus J Schulten;Jian Ping Zhang

  • Raman and infrared spectra of the all-trans, 7-cis, 9-cis, 13-cis and 15-cis isomers of β-carotene: Key bands distinguishing stretched or terminal-bent configurations form central-bent configurations

    Yasushi Koyama;Ichiro Takatsuka;Munetaka Nakata;Mitsuo Tasumi

  • The 1Bu+, 1Bu-, and 2Ag- Energies of Crystalline Lycopene, β-Carotene, and Mini-9-β-carotene as Determined by Resonance-Raman Excitation Profiles: Dependence of the 1Bu- State Energy on the Conjugation Length

    Tokutake Sashima and;Yasushi Koyama;Takashi Yamada and;Hideki Hashimoto

  • Separation and determination of cis/trans-β-carotenes by high-performance liquid chromatography

    Kiyoshi Tsukida;Kayoko Saiki;Tomoko Takii;Yasushi Koyama

  • Configuration of the carotenoid in the reaction centers of photosynthetic bacteria. Comparison of the resonance Raman spectrum of the reaction center of Rhodopseudomonas sphaeroides G1C with those of cis-trans isomers of β-carotene

    Yasushi Koyama;Mariko Kito;Tomoko Takii;Kayoko Saiki

  • Mechanism of the Carotenoid-to-Bacteriochlorophyll Energy Transfer via the S1 State in the LH2 Complexes from Purple Bacteria

    † Jian-Ping Zhang;Ritsuko Fujii;Pu Qian;Toru Inaba

  • A new singlet-excited state of all-trans-spheroidene as detected by resonance-Raman excitation profiles

    Tokutake Sashima;Hiroyoshi Nagae;Michitaka Kuki;Yasushi Koyama

  • The CC stretching Raman lines of [β-carotene isomers in the S1 state as detected by pump-probe resonance Raman spectroscopy

    Hideki Hashimoto;Yasushi Koyama

  • The first detection of the 3A g - state in carotenoids using resonance-Raman excitation profiles

    Kentaro Furuichi;Tokutake Sashima;Yasushi Koyama

  • Triplet-sensitized and thermal isomerization of all-trans, 7-cis, 9-cis, 13-cis and 15-cis isomers of .beta.-carotene: configurational dependence of the quantum yield of isomerization via the T1 state

    Michitaka Kuki;Yasushi Koyama;Hiroyoshi Nagae

  • Structure of the light-harvesting bacteriochlorophyll c assembly in chlorosomes from Chlorobium limicola determined by solid-state NMR

    Ayako Egawa;Toshimichi Fujiwara;Tadashi Mizoguchi;Yoshinori Kakitani

  • Raman spectra of chlorophyll forms

    Yasushi Koyama;Yasuhiro Umemoto;Atsuko Akamatsu;Kaku Uehara

  • Effect of protonation on the isomerization properties of n-butylamine Schiff base of isomeric retinal as revealed by direct HPLC analyses: selection of isomerization pathways by retinal proteins.

    Yasushi Koyama;Keishi Kubo;Mika Komori;Haruo Yasuda

  • The 2Ag− energies of all-trans-neurosporene and spheroidene as determined by fluorescence spectroscopy

    Ritsuko Fujii;Kengo Onaka;Michitaka Kuki;Yasushi Koyama

  • Dye-sensitized solar cells using a chlorophyll a derivative as the sensitizer and carotenoids having different conjugation lengths as redox spacers

    Xiao-Feng Wang;Junfeng Xiang;Peng Wang;Yasushi Koyama

  • Near-infrared time-resolved study of the S-1 state dynamics of the carotenoid spheroidene

    Tornáš Polívka;Donatas Zigmantas;Harry A. Frank;James A. Bautista

  • Vibronic Coupling through the In-Phase, CC Stretching Mode Plays a Major Role in the 2Ag- to 1Ag- Internal Conversion of all-trans-β-Carotene

    Hiroyoshi Nagae;Michitaka Kuki;Jian-Ping Zhang;Tokutake Sashima

  • Effects of plant carotenoid spacers on the performance of a dye-sensitized solar cell using a chlorophyll derivative: Enhancement of photocurrent determined by one electron-oxidation potential of each carotenoid

    Xiao-Feng Wang;Arihiro Matsuda;Yasushi Koyama;Hiroyoshi Nagae

  • S1 and T1 species of .beta.-carotene generated by direct photoexcitation from the all-trans, 9-cis, 13-cis, and 15-cis isomers as revealed by picosecond transient absorption and transient Raman spectroscopies

    Hideki Hashimoto;Yasushi Koyama;Yoshinori Hirata;Noboru Mataga

Frequent Co-Authors

Hideki Hashimoto
Hideki Hashimoto Kwansei Gakuin University
Xiao-Feng Wang
Xiao-Feng Wang Jilin University
Richard J. Cogdell
Richard J. Cogdell University of Glasgow
Hugo Scheer
Hugo Scheer Ludwig-Maximilians-Universität München
Yuji Wada
Yuji Wada Tokyo Institute of Technology
Hideki Hashimoto
Hideki Hashimoto Chuo University
Hitoshi Tamiaki
Hitoshi Tamiaki Ritsumeikan University
Kimiyuki Satoh
Kimiyuki Satoh Okayama University
Fuyuhiko Inagaki
Fuyuhiko Inagaki Hokkaido University
Tatsuya Tomo
Tatsuya Tomo Tokyo University of Science

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Best Scientists Citing Yasushi Koyama

Richard J. Cogdell

Richard J. Cogdell

University of Glasgow

Publications: 86

Hitoshi Tamiaki

Hitoshi Tamiaki

Ritsumeikan University

Publications: 83

Hideki Hashimoto

Hideki Hashimoto

Kwansei Gakuin University

Publications: 70

Tomáš Polívka

Tomáš Polívka

University of South Bohemia in České Budějovice

Publications: 65

Harry A. Frank

Harry A. Frank

University of Connecticut

Publications: 54

Bruno Robert

Bruno Robert

University of Paris-Saclay

Publications: 38

Xiao-Feng Wang

Xiao-Feng Wang

Jilin University

Publications: 27

Villy Sundström

Villy Sundström

Lund University

Publications: 25

Rienk van Grondelle

Rienk van Grondelle

Vrije Universiteit Amsterdam

Publications: 24

Graham R. Fleming

Graham R. Fleming

University of California, Berkeley

Publications: 24

C. Neil Hunter

C. Neil Hunter

University of Sheffield

Publications: 22

Roger G. Hiller

Roger G. Hiller

Macquarie University

Publications: 21

Lowell D. Kispert

Lowell D. Kispert

University of Alabama

Publications: 17

Robert E. Blankenship

Robert E. Blankenship

Washington University in St. Louis

Publications: 16

Johan Lugtenburg

Johan Lugtenburg

Leiden University

Publications: 16

Hiro-o Hamaguchi

Hiro-o Hamaguchi

National Yang Ming Chiao Tung University

Publications: 16

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