Researcher Database

Suzuki Kimichi
Creative Research Institution Institute for Chemical Reaction Design and Discovery
Specially Appointed Associate Professor

Researcher Profile and Settings

Affiliation

  • Creative Research Institution Institute for Chemical Reaction Design and Discovery

Job Title

  • Specially Appointed Associate Professor

J-Global ID

Research Activities

Published Papers

  • Suzuki Kimichi, Maeda Satoshi, Morokuma Keiji
    ACS Omega 4 (1) 1178 - 1184 2019 [Refereed][Not invited]
  • Satoshi Maeda, Yu Harabuchi, Makito Takagi, Kenichiro Saita, Kimichi Suzuki, Tomoya Ichino, Yosuke Sumiya, Kanami Sugiyama, Yuriko Ono
    JOURNAL OF COMPUTATIONAL CHEMISTRY 39 (4) 233 - 250 0192-8651 2018/02 [Refereed][Not invited]
     
    This article reports implementation and performance of the artificial force induced reaction (AFIR) method in the upcoming 2017 version of GRRM program (GRRM17). The AFIR method, which is one of automated reaction path search methods, induces geometrical deformations in a system by pushing or pulling fragments defined in the system by an artificial force. In GRRM17, three different algorithms, that is, multicomponent algorithm (MC-AFIR), single-component algorithm (SC-AFIR), and double-sphere algorithm (DS-AFIR), are available, where the MC-AFIR was the only algorithm which has been available in the previous 2014 version. The MC-AFIR does automated sampling of reaction pathways between two or more reactant molecules. The SC-AFIR performs automated generation of global or semiglobal reaction path network. The DS-AFIR finds a single path between given two structures. Exploration of minimum energy structures within the hypersurface in which two different electronic states degenerate, and an interface with the quantum mechanics/molecular mechanics method, are also described. A code termed SAFIRE will also be available, as a visualization software for complicated reaction path networks. (c) 2017 The Authors. Journal of Computational Chemistry Published by Wiley Periodicals, Inc.
  • Kimichi Suzuki, Yukio Kawashima, Masanori Tachikawa
    Frontiers of Quantum Chemistry Springer Singapore 377  2017/11 [Refereed][Not invited]
  • Kimichi Suzuki, Keiji Morokuma, Satoshi Maeda
    JOURNAL OF COMPUTATIONAL CHEMISTRY 38 (26) 2213 - 2221 0192-8651 2017/10 [Refereed][Not invited]
     
    We propose a multistructural microiteration (MSM) method for geometry optimization and reaction path calculation in large systems. MSM is a simple extension of the geometrical microiteration technique. In conventional microiteration, the structure of the non-reaction-center (surrounding) part is optimized by fixing atoms in the reaction-center part before displacements of the reaction-center atoms. In this method, the surrounding part is described as the weighted sum of multiple surrounding structures that are independently optimized. Then, geometric displacements of the reaction-center atoms are performed in the mean field generated by the weighted sum of the surrounding parts. MSM was combined with the QM/MM-ONIOM method and applied to chemical reactions in aqueous solution or enzyme. In all three cases, MSM gave lower reaction energy profiles than the QM/MM-ONIOM-microiteration method over the entire reaction paths with comparable computational costs. (c) 2017 Wiley Periodicals, Inc.
  • Taro Udagawa, Keita Sugiura, Kimichi Suzuki, Masanori Tachikawa
    RSC ADVANCES 7 (15) 9328 - 9337 2046-2069 2017 [Refereed][Not invited]
     
    Isomerization and keto-enol tautomerism reactions of the pyruvic acid molecule have been investigated using the multicomponent B3LYP (MC_B3LYP) methods, which can take account of the nuclear quantum effect (NQE) of a light nucleus, such as a proton and a deuteron. While the conventional harmonic zero point vibrational energy (ZPVE) correction makes the activation energies of all the reactions in this system lower, a contrasting behavior is found in our MC_B3LYP results for several rotational reactions. In such cases, the H/D isotope effect on the activation energy is also completely opposite between harmonic ZPVE-corrected B3LYP and MC_B3LYP calculations. In our MC_B3LYP calculation, the activation energies of several C-C or O-H rotational reactions of H species are slightly higher than those of D species, since the NQE of a hydrogen-bonded proton strengthens the hydrogen-bonded interaction more than that of a deuteron, and, thus, the rotational motion of H species is restricted. Such an "unusual" H/D isotope effect on the activation energies can be observed only in the MC_B3LYP results. Our MC_B3LYP calculations clearly demonstrate that direct inclusion of NQE is indispensable to analyze H/D isotope effects on activation energies of not only hydrogen transfer reactions but also C-C and O-H rotational reactions in the isomerization and keto-enol tautomerism of pyruvic acid molecule.
  • Taro Udagawa, Kimichi Suzuki, Masanori Tachikawa
    INTERNATIONAL CONFERENCE ON COMPUTATIONAL SCIENCE (ICCS 2017) 108 2275 - 2281 1877-0509 2017 [Refereed][Not invited]
     
    H-2 dissociation on small aluminum cluster, Al-2, is studied using our multicomponent quantum-mechanical (MC_QM) method, which can take account of the nuclear quantum effect (NQE) of light nucleus, such as proton and deuteron. We demonstrate that no standard density functionals can reproduce CCSD(T) geometry of van der Waals Al-2. H-2 complex well, even though the empirical dispersion correction is included. Our MC_QM calculations reveal that NQE stabilizes structures at each stationary point, and H-2 dissociation reaction is the barrierless reaction on the MC_QM effective potential energy hypersurface. The H/D isotope effect on the dissociation reaction are also analyzed. (C) 2017 The Authors. Published by Elsevier B.V.
  • Taro Udagawa, Kimichi Suzuki, Masanori Tachikawa
    CHEMPHYSCHEM 16 (15) 3156 - 3160 1439-4235 2015/10 [Refereed][Not invited]
     
    To analyze the H/D isotope effects on hydrogen transfer reactions in XHCHCHCHYXCHCHCHYH (X, Y=O, NH, or CH2) including the nuclear quantum effect of proton and deuteron, we propose a multicomponent molecular orbital-climbing image-nudged elastic band (MC_MO-CI-NEB) method. We obtain not only transition state structures but also minimum-energy paths (MEPs) on the MC_MO effective potential energy surface by using MC_MO-CI-NEB method. We find that nuclear quantum effect affects not only stationary-point geometries but also MEPs and electronic structures in the reactions. We clearly demonstrate the importance of including nuclear quantum effects for H/D isotope effect on rate constants (k(H)/k(D)).
  • Hirotomo Nishihara, Somlak Ittisanronnachai, Hiroyuki Itoi, Li-Xiang Li, Kimichi Suzuki, Umpei Nagashima, Hiroshi Ogawa, Takashi Kyotani, Masashi Ito
    JOURNAL OF PHYSICAL CHEMISTRY C 118 (18) 9551 - 9559 1932-7447 2014/05 [Refereed][Not invited]
     
    Hydrogen storage in metal-doped carbons through a spillover mechanism has attracted a great attention. However, the data reported so far are lacking in consistency among different research groups, and the mechanism has not been fully revealed yet. In this work, we prepare a model Pt-loaded carbon by a simple and reproducible method in which already-synthesized Pt-nanocolloid is directly doped on zeolite-templated carbon. The Pt-loaded carbon thus obtained provides reliable data as for the temperature effects (273-353 K) on hydrogen/deuterium (H/D) adsorption isotherms, which contain the contributions of H-2/D-2 physisorption, H/D chemisorption on Pt surface, and H/D storage by the spillover mechanism. We extracted the last contribution (spillover HID) from the isotherms, and found that the amount of the spillover H/D increases with increasing pressure (up to 100 kPa) and temperature (273-353 K). Detailed analysis of the number of H/D atoms stored by the spillover mechanism reveals that H/D radicals spilling from the Pt surface migrate on the carbon surface. The path integral molecular dynamics simulation also demonstrates the migration of atomic H/D on a model fragment of the zeolite-templated carbon, and suggests the enhancement of migration at higher temperature.
  • Qi Wang, Kimichi Suzuki, Umpei Nagashima, Masanori Tachikawa, Shiwei Yan
    CHEMICAL PHYSICS 419 229 - 236 0301-0104 2013/06 [Refereed][Not invited]
     
    The nuclear quantum effect, which plays important roles on ionic hydrogen bonded structures of Cl-(H2O)(n) (n = 1-4) clusters, was explored by carrying out path integral molecular dynamic simulations. An outer shell coordinate r(l)(Cl center dot center dot center dot O) is selected to display the rearrangement of single and multi hydration shell cluster structures. By incorporating the nuclear quantum effect, it is shown that the probability for single shell structures is decreased while the probability for multi shell structures is increased. On the other hand, the correlations between changing of bonded H* atom to Cl- (defined as delta) and other cluster vibration coordinates are studied. We have found that delta strongly correlates with proton transfer motion while it has little correlation with ion-water stretching motion. Contrary to theta(H-O-H*) coordinate, the correlations between delta and other coordinates are decreased by inclusion of nuclear quantum effect. The results indicate that the water-water hydrogen bond interactions are encouraged by quantum simulations. (C) 2013 Elsevier B. V. All rights reserved.
  • Yukio Kawashima, Kimichi Suzuki, Masanori Tachikawa
    JOURNAL OF PHYSICAL CHEMISTRY A 117 (24) 5205 - 5210 1089-5639 2013/06 [Refereed][Not invited]
     
    Small hydrated fluoride ion complexes, F-(H2O) (n = 1-3), have been studied by ab initio hybrid Monte Carlo (HMC) and ab initio path integral hybrid Monte Carlo (PIHMC) simulations. Because of the quantum effect, our simulation shows that the average hydrogen-bonded F-center dot center dot center dot HO distance in the quantum F-(H2O) is shorter than that in the classical one, while the relation inverts at the three water molecular F-(H2O)(3) cluster. In the case of F-(H2O)(3), we have found that the nuclear quantum effect enhances the formation of hydrogen bonds between two water molecules. In F-(H2O)(2) and F-(H2O)(3), the nuclear quantum effect on two different kinds of hydrogen bonds, F--water and water-water hydrogen bonds, competes against each other. In F-(H2O)(3), thus, the nuclear quantum effect on the water-water hydrogen bond leads to the elongation of hydrogen-bonded F-center dot center dot center dot HO distance, which we suggest this as the possible origin of the structural inversion from F-(H2O) to F-(H2O)(3).
  • Kimichi Suzuki, Masanori Tachikawa, Motoyuki Shiga
    JOURNAL OF CHEMICAL PHYSICS 138 (18) 0021-9606 2013/05 [Refereed][Not invited]
     
    Temperature dependence on the structural fluctuations of Zundel cation, H5O2+, and its isotopomers, D5O2+ and T5O2+, have been studied using path integral molecular dynamics simulations in which nuclear quantum effect is fully taken into account. It has been found that the fluctuations of hydrogen-oxygen and oxygen-oxygen distances, which are relevant to the hydrogen bonded structure, grow drastically as the temperature increases within the range of investigation between 100 K and 900 K. The fluctuation with respect to the position of non-bonded hydrogen also increases substantially as the temperature increases. The temperature dependence on the fluctuation is greater for D5O2+ or T5O2+ than that of H5O2+, since the zero-point effect of the former is less than the latter. (C) 2013 AIP Publishing LLC.
  • Qi Wang, Kimichi Suzuki, Umpei Nagashima, Masanori Tachikawa, Shiwei Yan
    Chemical Physics 426 38 - 47 0301-0104 2013 [Refereed][Not invited]
     
    The geometric isotope effects on the structures of hydrated chloride ionic hydrogen bonded clusters are explored by carrying out path integral molecular dynamics simulations. First, an outer shell coordinate is selected to display the rearrangement of single and multi hydration shell cluster structures. Next, to show the competition of intramolecular and intermolecular nuclear quantum effects, the intramolecular OH* stretching and intermolecular ion-water wagging motions are studied for single and multi shell structures, respectively. The results indicate that the intermolecular nuclear quantum effects stabilize the ionic hydrogen bonds in single shell structures, while they are destabilized through the competition with intramolecular nuclear quantum effects in multi shell structures. In addition, the correlations between ion-water stretching motion and other cluster vibrational coordinates are discussed. The results indicate that the intermolecular nuclear quantum effects on the cluster structures are strongly related to the cooperation of the water-water hydrogen bond interactions. © 2013 Elsevier B.V. All rights reserved.
  • Akihito Koizumi, Kimichi Suzuki, Motoyuki Shiga, Masanori Tachikawa
    INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY 112 (1) 136 - 139 0020-7608 2012/01 [Refereed][Not invited]
     
    Ab initio path integral molecular dynamics simulation of MOH(H2O) (M = Cu, Ag, and Au) clusters has been performed to analyze how the hydrogen-bonded proton can be affected by the counter noble metal cation. The CuOH(H2O) cluster does not form hydrogen bonded structure even for the static equilibrium structures. Contrary to our previous article of hydrated alkali metal hydroxide clusters (Koizumi et al., J Chem Phys 2011, 134, 031101), proton transferred distribution was not observed because of the high potential barrier heights of MOH(H2O). (C) 2011 Wiley Periodicals, Inc. Int J Quantum Chem 112: 136-139, 2012
  • Kimichi Suzuki, Masanori Tachikawa, Hiroshi Ogawa, Somlak Ittisanronnachai, Hirotomo Nishihara, Takashi Kyotani, Umpei Nagashima
    THEORETICAL CHEMISTRY ACCOUNTS 130 (4-6) 1039 - 1042 1432-881X 2011/12 [Refereed][Not invited]
     
    To analyze the proton/deuteron (H/D) isotope effect on the stable adsorption sites on zeolite-templated carbon (ZTC), we have performed path integral molecular dynamics simulations including thermal and nuclear quantum effects with the semi-empirical PM3 potential at 300 K. Here, for the adsorption sites of additional proton (H*) and deuteron (D*), we chose different five carbon atoms labeled as alpha-, beta(1)-, beta(2)-, gamma-, and delta-carbons from edge to bottom for inside of buckybowl (C(36)H(12) and C(36)D(12)). The stable adsorption sites of D* are observed on all carbon atoms, while those of H* are not observed on delta-carbon atom, but only on alpha-, beta(1)-, beta(2)-, and gamma-carbon atoms. This result is explained by the fact that H* can easily go over the barrier height for hydrogen transferring from delta- to beta(2)-carbons at 300 K, since the zero-point energy of H* is greater than that of D*.
  • Kimichi Suzuki, Megumi Kayanuma, Masanori Tachikawa, Hiroshi Ogawa, Hirotomo Nishihara, Takashi Kyotani, Umpei Nagashima
    COMPUTATIONAL AND THEORETICAL CHEMISTRY 975 (1-3) 128 - 133 2210-271X 2011/11 [Refereed][Not invited]
     
    To evaluate the adsorption sites of hydrogen atom on buckybowl-like molecule (C(36)H(12)), which is a model fragment structure of zeolite-templated carbon (ZTC), we have performed path integral molecular dynamics (PIMD) simulation including thermal and nuclear quantum fluctuations under the semi-empirical PM3 potential. Here we have picked up ten carbons as the adsorption sites of additional hydrogen atom (H*), which are labeled as alpha-, beta(1)-, beta(2)-, gamma-, and delta-carbon from edge to bottom carbon for inside and outside of C(36)H(12), respectively. In the static PM3 calculation and conventional MD simulation the ten stable adsorption sites of H* are obtained both inside and outside of C(36)H(12). In PIMD simulation, on the other hand, the nine stable adsorption sites are obtained, except for delta-carbon for inside of C(36)H(12). This result is due to the fact that the thermal effect and zero point vibration of delta-carbon and FP stretching motion make adsorbed hydrogen atom go over potential barrier from delta- and beta(1)-carbon for inside of C(36)H(12) more readily. The thermal and nuclear quantum effects are important to evaluate the hydrogen adsorption site on carbon materials. (C) 2011 Elsevier B.V. All rights reserved.
  • Kimichi Suzuki, Megumi Kayanuma, Masanori Tachikawa, Hiroshi Ogawa, Hirotomo Nishihara, Takashi Kyotani, Umpei Nagashima
    JOURNAL OF ALLOYS AND COMPOUNDS 509 (SUPPL. 2) S868 - S871 0925-8388 2011/09 [Refereed][Not invited]
     
    To settle the hydrogen adsorption sites on buckybowl C(36)H(12), which is picked up from zeolite-templated carbon (ZTC), we have performed path integral molecular dynamics (PIMD) simulation including thermal and nuclear quantum fluctuations under semi-empirical PM3 method. In the static PM3 calculation and classical simulation the five stable adsorption sites of hydrogen atom are optimized inside a buckybowl C(36)H(12), which are labeled as alpha-, beta(1)-, beta(2)-, gamma-, and delta-carbons from edge to innermost carbon. In PIMD simulation, meanwhile, stable adsorption site is not appeared on delta-carbon, but on only alpha-, beta(1)-, beta(2)-, and gamma-carbons. This result is due to the fact that the adsorbed hydrogen atom can easily go over the barrier for hydrogen transferring from delta- to beta(1)-carbons by thermal and nuclear quantum fluctuations. The thermal and nuclear quantum effects are key role to settle the hydrogen adsorption sites on carbon materials. (C) 2010 Elsevier B.V. All rights reserved.
  • Akihito Koizumi, Kimichi Suzuki, Motoyuki Shiga, Masanori Tachikawa
    JOURNAL OF CHEMICAL PHYSICS 134 (3) 0021-9606 2011/01 [Refereed][Not invited]
     
    Ab initio path integral molecular dynamics simulation of M(+)(H(3)O(2)(-)) (M=Li, Na, and K) has been carried out to analyze how the structure and dynamics of a low-barrier hydrogen-bonded Zundel anion, H(3)O(2)(-), can be affected by the counter alkali metal cation, M(+). Our simulation predicts that the quantum proton transfer in Zundel anion can be strongly coupled to the motion of counter cation located nearby. A smaller cation can induce larger structural distortion of the Zundel anion fragment making the proton transfer barrier higher, and hence, lower the vibrational excitation energy. It is also argued that a large H/D isotope effect is present. (C) 2011 American Institute of Physics. [doi:10.1063/1.3544212]
  • Kimichi Suzuki, Masanori Tachikawa, Motoyuki Shiga
    JOURNAL OF CHEMICAL PHYSICS 132 (14) 0021-9606 2010/04 [Refereed][Not invited]
     
    We propose an efficient path integral hybrid Monte Carlo (PIHMC) method based on fourth-order Trotter expansion. Here, the second-order effective force is employed to generate short trial trajectories to avoid computationally expensive Hessian matrix, while the final acceptance is judged based on fourth-order effective potential. The computational performance of our PIHMC scheme is compared with that of conventional PIHMC and PIMD methods based on second- and fourth-order Trotter expansions. Our method is applied to on-the-fly ab initio PIHMC calculation of fluoride ion-water complexes, F(-)(H(2)O) and F(-)(D(2)O), at ambient temperature, particularly focusing on the geometrical isotope effect.
  • Motoyuki Shiga, Kimichi Suzuki, Masanori Tachikawa
    JOURNAL OF CHEMICAL PHYSICS 132 (11) 0021-9606 2010/03 [Refereed][Not invited]
     
    The (1)H NMR chemical shift in deprotonated water dimer H(3)O(2)(-) has been studied by ab initio path integral simulation. The simulation predicts that the isotropic shielding of hydrogen-bonded proton increases as a function of temperature by about 0.003 ppm/K. This change is about an order of magnitude larger than that of the nonhydrogen-bonded proton. It is concluded that this is caused by the significant difference in the quantum distribution of proton at high and low temperatures in the low barrier hydrogen bond.
  • Kimichi Suzuki, Motoyuki Shiga, Masanori Tachikawa
    JOURNAL OF CHEMICAL PHYSICS 129 (14) 0021-9606 2008/10 [Refereed][Not invited]
     
    Path integral molecular dynamics simulation based on the fourth order Trotter expansion has been performed to elucidate the geometrical isotope effect of water dimer anions, H(3)O(2)(-), D(3)O(2)(-), and T(3)O(2)(-), at different temperatures from 50 to 600 K. At low temperatures below 200 K the hydrogen- bonded hydrogen nucleus is near the center of two oxygen atoms with mostly O center dot center dot center dot X center dot center dot center dot O geometry (where X = H, D, or T), while at high temperatures above 400 K, hydrogen becomes more delocalized, showing the coexistence between O center dot center dot center dot X-O and O-X center dot center dot center dot O. The OO distance tends to be shorter as the isotopomer is heavier at low temperatures, while this ordering becomes opposite at high temperatures. It is concluded that the coupling between the OO stretching mode and proton transfer modes is a key to understand such a temperature dependence of a hydrogen- bonded structure. (C) 2008 American Institute of Physics.


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