Optical spectrum prediction based on first-principles calculations is important for the development of optical materials. In particular, Time Dependent Density Functional Theory (TDDFT) in real-time is one of the most widely used calculation methods. In real-time TDDFT, the dynamic dipole moment is used to obtain the polarizability by Fourier transform (FT). The optical spectrum can be obtained from this polarizability. However, if the time length is not sufficient, the spectrum resolution depends on the length and becomes ambiguous. To solve this problem, we introduced Dynamic Mode Decomposition (DMD). This spectral analysis technique uses both Singular Value Decomposition and Proper Orthogonal Decomposition to obtain frequencies and intensities of spectrum. The signal frequency and the intensity are directly obtained. This method was applied to TDDFT time series data for ethylene and small molecules of benzene, naphthalene, anthracene, and tetracene. Compared to conventional FT, clear spectra were obtained from a short time series data.

Molecular dynamics (MD) simulations, accelerated by a universal neural network potential, were employed to investigate the dynamic behaviors of ten inorganic anions (Br-, Cl-, F-, OH-, NO3-, H2PO2-, H2PO3-, HPO42-, CO32- and SO42-) intercalated into NiFe layered double hydroxide at varying hydration levels. Our results show that the lattice parameters along the layered double hydroxide (LDH) layers are minimally affected by the intercalated anions and water content, while the lattice parameter perpendicular to the layers, i.e., the basal spacing, is strongly influenced by the type of anion and hydration level. The basal spacing is closely correlated with the ionic radius and charge of the anions, as well as the amount of water uptake. Mean squared displacement (MSD) analysis reveals distinct behaviors of the anions under different hydration conditions. While some anions, such as NO3- and H2PO2-, exhibit noticeable mobility, others remain largely immobilized, primarily due to strong electrostatic interactions with the LDH layers and water molecules. Hydration weakens the interaction between anions and the LDH but also restricts the mobility of anions due to the formation of hydration shells. These findings provide insights into anion dynamics and selectivity in NiFe LDH, which are critical for designing materials for anion removal applications.

Dimethyl sulfoxide (DMSO), widely used as a cryoprotectant, drug, and oxidant, contains a hydrophilic S=O and hydrophobic CH3 groups and is fully miscible with water in any ratio. In this study, intermolecular interactions in dilute aqueous DMSO solution were analyzed using effective fragment potential based molecular dynamics (EFP-MD) simulations. The analysis revealed that DMSO induced stable interactions with water molecules not only around its hydrophilic S=O group but also near the CH3 groups. The interaction lifetimes suggested that the hydrogen bonding network in the first hydration shell is directional.

It is known that it is possible to develop a chemically intelligent robot that can perceive spatial extent using the BZ reaction. If the BZ reaction can be used for learning, there is a possibility of developing a chemically intelligent robot that can make complex judgments about situations like living organisms. In the physical reservoir calculation, it is possible to construct a learning system using a material system, so in this study, we build a physical reservoir calculation using the BZ reaction and confirmed that learning is possible. The physical reservoir computation was capable of performing tasks such as time series prediction and speech recognition. BZ reaction, nonlinear chemical reaction, reservoir computing, time series prediction, speech recognition

S0/S1極小エネルギー円錐交差(MECI)の支配因子を評価するために，スピン反転時間依存密度汎関数理論に対する凍結軌道解析(FZOA)の波動関数と励起エネルギーを導出した．スピン反転法に特有のスピン汚染を避けるため，定式化においてスピン完全法を適用した．数値計算の結果，「HOMO−LUMO交換積分がほぼ0となる」，「HOMO−LUMOギャップの上限値はHOMO，LUMOが関係するCoulomb積分によって定まる」というS0/S1 MECIの支配因子を発見した．本論文では，FZOAについて概説するとともに，スピン反転法におけるFZOAの定式化について述べる．導出したスピン反転FZOAの式をエチレンとウラシルに適用した結果に基づいて，励起エネルギー成分に基づく支配因子の発見，S0/S1 MECIの電子構造，これらの制限付き開殻法における結合係数への依存性について解説する．

メタノール4分子の環状クラスター(CH3OH)4のOH基とCを同一面内に配置した初期構造から構造最適化計算を行った．HF/STO-3Gでは，初期構造のO-O間距離が2.7 Å以上の場合に最安定構造が高い頻度で得られる．O-O間距離が短い場合には他の安定な配座異性体が2種類得られる．この約2.7 Åの距離はOH基の水素結合力の範囲を示唆する．HF/6-31G (d)では，虚振動を持つ平面構造で収束する．B3LYP/6-31G (d)では，メチル基が環面外の同じ側に向いた構造で収束する．これらの結果は，酸素の非共有電子対の軌道の広がりによる安定化とメチル基の反発力の均衡から説明でき，配座異性体同士の変換傾向を反映する．計算過程で力定数を計算(calcall)すると初期O-O間距離に関わらず最安定構造が得られる．

酸化チタン光触媒の表面反応を理論計算で考察する時に，従来から用いられている平面型チタン二量体モデルの電子状態を調べた．用いた計算方法はB3LYP/6-311Gで，末端を水酸基化した初期構造(Ti2O6H4)を最適化計算した．水酸基の初期の配向によって結果が異なり，非平面構造を取り易いことがわかった．また，HOMOとLUMOのエネルギー準位の比較から，光触媒反応の酸化力と還元力に水素の位置が重要であることがわかった．チタン二量体モデルのみでは電子状態の記述に無理があり，周辺構造を含めた新しい表面モデルの構築が必要であることが示唆された．

Material Informatics (MI) needs large amount of data about materials. However, the cost of data extraction is very high. Therefore, chemical researchers are interested in technology to automatically extract the data from published documents such as patents. Previous technologies can extract the data from text in patents, but not tables. Therefore, we develop the data for MI extraction method from texts and tables in patents. In our evaluation, our method can reduce the time of data extraction by one-half. In the results, it can be expected that the new method can sufficiently reduce the cost of data extraction.