The present study applies all-electron relativistic DFT calculation with Douglas-Kroll-Hess (DKH) Hamiltonian to each ten sets of Ru and Os compounds. We perform the benchmark investigation of three density functionals (BP86, B3LYP and B2PLYP) using segmented all-electron relativistically contracted (SARC) basis set with the experimental Mössbauer isomer shifts for 99 Ru and 189 Os nuclides. Geometry optimizations at BP86 theory of level locate the structure in a local minimum. We calculate the contact density to the wavefunction obtained by a single point calculation. All functionals show the good linear correlation with experimental isomer shifts for both 99 Ru and 189 Os. Especially, B3LYP functional gives a stronger correlation compared to BP86 and B2PLYP functionals. The comparison of contact density between SARC and well-tempered basis set (WTBS) indicated that the numerical convergence of contact density cannot be obtained, but the reproducibility is less sensitive to the choice of basis set. We also estimate the values of ΔR/R, which is an important nuclear constant, for 99 Ru and 189 Os nuclides by using the benchmark results. The sign of the calculated ΔR/R values is consistent with the predicted data for 99 Ru and 189 Os. We obtain computationally the ΔR/R values of 99 Ru and 189 Os (36.2 keV) as 2.35 × 10-4 and-0.20 × 10-4 , respectively, at B3LYP level for SARC basis set.

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The relation between concentration of elements and microbial activity in the water samples of Higashi-Hiroshima Campus, Hiroshima University was investigated. Energy dispersive X-ray spectroscopy revealed that microbial mat contains iron, aluminium, silicon and phosphorus. Model experiment revealed that the potassium was adsorbed by living microorganism in the microbial mats, while it was not adsorbed by dead microbial mat. Iron was adsorbed by both living and dead microbial mats. The present results explain the increase in the total β-radioactivity of water sample in summer and the decrease in winter.

Benchmark study of density functional theory by using Mössbauer spectroscopic parameters and its application to d-, f-block coordination chemistry (メスバウアー分光パラメータを用いた密度汎関数法のベンチマーク研究と d, f ブロック錯体化学への応用) 広島大学大学院理学研究科化学専攻 金子政志 Chapter 1. General introduction メスバウアー分光は、着目する原子核の γ 線共鳴を観測し、得られるパラメータは分子中の結合状 態を定量的に記述する。密度汎関数法(DFT)は、遷移金属化合物の電子状態を評価する手法として優れて いるが、結合状態の評価は交換・相関ポテンシャルに含まれる経験的パラメータによって異なる。本論 文では、メスバウアー分光パラメータをベンチマーク指標として DFT を最適化し、その理論を用いて d, f ブロック錯体に関する計算化学的アプローチについて述べる。 Chapter 2. Theoretical background 本章では、着目する事象や用いる計算手法の概要を述べる。まず、Fe(II)錯体の spin-crossover (SCO) 現象の紹介や関連する DFT 研究について示す。次に、参照する実験値であるメスバウアー異性体シフト について概説する。最後に、重元素の計算に必要な相対論ハミルトニアンについて述べる。 Chapter 3. Computational chemical study on spin-crossover on/off behavior of [Fe(NCX) 2 (bpa) 2 ] n (X = S, Se,