Makito Takagi

Yokohama City University | YCU · Department of Materials System Science

We propose an approach to perform the global search for low-lying crystal structures from first principles, by combining the artificial force induced reaction (AFIR) method and the periodic boundary conditions (PBCs). The AFIR method has been applied extensively to molecular systems to elucidate the mechanism of chemical reactions such as homogeneo...

Practical electrochemical water splitting and carbon-dioxide reduction are desirable for a sustainable energy society. In particular, facilitating the oxygen evolution reaction (OER, the reaction at the anode) will increase the efficiency of these reactions. Nickel (Ni) compounds are excellent OER catalysts under basic conditions, and atomically pr...

Although positron binding to van der Waals intermolecularly bonded clusters of non-polar carbon dioxide (CO2) molecules was experimentally suggested, the positron binding feature has been poorly understood. We investigated positron affinities (PAs) by means of multi-component configuration interaction calculations for various structures of (CO2)n (...

In recent years, supramolecular cocrystals containing organic donors and acceptors have been explored as active components in organic field-effect transistors (FETs). Herein, we report the synthesis of novel single-cocrystal nanoribbons with ambipolar charge transport characteristics from C70 and 5,10,15,20-tetrakis(3,5-dimethoxyphenyl)porphyrin (3...

Recently, cocrystals containing organic donors and acceptors have been explored as active elements in organic field-effect transistors (FETs). Herein, we report the ambipolar charge transport properties of C60/ferrocene (C60/Fc) single...

In this study, a systematic search for structures of carbon crystals under high pressure was performed by using the artificial force induced reaction method including periodic boundary conditions. To perform a search under an arbitrary pressure, an algorithm to take account of the pressure was implemented in the GRRM program. At 100 GPa, the search...

In this study, we focused on the effect of pressure on the crystal structures of dioxides of group 14 elements, i.e. SiO2, GeO2, and CO2. Systematic searches for their crystal structures using the artificial force induced reaction method generated 219 and 147, 102 and 63, and 148 and 76 structures for SiO2, GeO2, and CO2, respectively, at 1 and 10⁶...

In this study, a systematic search for structures of carbon crystal under ultrahigh pressure was performed by using the artificial force induced reaction method including periodic boundary conditions (PBC/SC-AFIR). To perform a search under an arbitrary pressure, an algorithm to take account of pressure was implemented in the GRRM program. At 100 G...

Recently, organic donor-acceptor (D-A) cocrystals have attracted special interest as functional materials because they have unique chemical and physical properties that are not exhibited by simple mixtures of the components. Herein, we report the preparation of one-dimensional novel D-A cocrystals from C60 and 5,10,15,20-tetrakis(3,5-dimethoxypheny...

Interfaces in nanocarbon materials are highly important, as they determine the properties of carbon-based devices. In terms of carrier and thermal transport properties, the interfacial features are often more important than the intrinsic characteristics. Herein, we describe how one-minute Joule annealing of carbon nanotube (CNT) yarns can convert t...

Atomic clusters generally possess many structural isomers due to the degrees of freedom. Conventional theoretical studies begin by searching stable structures for clusters followed by analyzing the electronic properties for the lowest energy isomer. Recent development in structural and chemical reaction pathway search technique allows us to investi...

Analysis of reaction on a solid surface is important task for understanding catalytic reaction mechanism. In this study, we studied CO oxidation on Pt(111) surface by using the artificial force induced reaction (AFIR) method. Systematic reaction path search was done, and the reaction route network was created. This network included not only bond re...

Catalytic bond activation pathways of diatomic molecules on small metal clusters have been studied by density functional theory calculations. The focus of this study is dissociation of NO, N₂, and O₂ on hexamers of eight transition metals (Ni, Cu, Rh, Pd, Ag, Ir, Pt, and Au). For all the 24 cases, the lowest energy structures at the molecular‐adsor...

In nanocatalysis a growing attention has recently been given to investigation of energetically low-lying structural isomers of atomic clusters, because some isomers can demonstrate better catalytic activity than the most stable structures. In this study, we present a comparative investigation of a catalytic activity for NO dissociation of a pair of...

The intersystem crossing (ISC) pathways of triplet benzene molecules in a benzene crystal were investigated theoretically. A combination of the gradient projection (GP) method, which is a standard method for optimizing the crossing seam of two potential energy surfaces, and the single-component artificial-force-induced reaction (SC-AFIR) method (GP...

In this study, artificial force induced reaction (AFIR) method, which has been utilized extensively in molecular systems, was applied to surface adsorbed species. A systematic strategy for obtaining path networks for surface adsorbed species is described for future applications to various surface reactions. As a case study, global reaction route ma...

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...

In this account, a technical overview of the artificial force induced reaction (AFIR) method is presented. The AFIR method is one of the automated reaction-path search methods developed by the authors, and has been applied extensively to a variety of chemical reactions, such as organocatalysis, organometallic catalysis, and photoreactions. There ar...

This work present results of a systematic investigation of adsorption and dissociation of H2 on the neutral, positively, and negatively charged gold clusters Aunq (n = 2–11; q = 0, ±1) using the global reaction route mapping (GRRM) technique combined with the anharmonic downward distortion following (ADDF) and the artificial force-induced reaction...