Theoretical Study of Spin Crossover Dynamics and Cooperativity in Transition-Metal Complex Crystals

2021 Fiscal Year Final Research Report

• Project/Area Number: 18K14234
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 34010:Inorganic/coordination chemistry-related
• Research Institution: Yamagata University
• Principal Investigator: Ando Hideo 山形大学, 理学部, 講師 (00754946)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: 遷移金属錯体結晶 / 電子・スピン状態 / イオンの細孔内運動

Outline of Final Research Achievements

Focusing on various iron complex crystals, including Prussian blue, we theoretically investigated how the distortion of the crystal structure, the changes in electronic and spin states, and the nuclear motions of endohedral ions are mutually coupled. We demonstrated that a differential spin density map can evidently visualize the complicated electronic and spin states of iron complex crystals, thereby clarifying the cooperative changes in the electronic/spin states and the motion of an endohedral ion. In addition, we developed a computational program, which combines electronic structure calculations and nuclear wave-function calculations, and extended the conventional energy decomposition analysis to incorporate the delocalization of nuclear wave functions. Our approach will help deepen the understanding of the cooperative phenomena in transition-metal complex crystals.

Free Research Field

理論物理化学

Academic Significance and Societal Importance of the Research Achievements

金属錯体結晶は多様な物性を示すことで今日，注目を集めている．しかし，結晶内部のイオン・分子の運動や結晶の構造歪み，電子・スピン状態の変化が複雑に絡みあい，化学的な直観のみでは物性の理解がしばしば難しい．ミクロの構造・運動とマクロの物性とを論理的に結びつける理論研究が求められている．本研究ではプルシアンブルー等の様々な鉄錯体結晶を取り上げ，「可視化」を突破口に混沌とした現象を丹念に解析した．また，電子と原子核の運動を量子力学的に記述する理論を組み合わせ，独自プログラムを開発・応用した．金属錯体結晶を用いた機能性材料の戦略的設計に道筋をつける試みである．