(57) 血红蛋白模型系统的Fe Mössbauer异构体转移:电子结构计算
Yong Zhang1, Junhong Mao, Eric Oldfield
1Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL 61801, USA.
Journal of the American Chemical Society
|June 27, 2002
概括
密度函数理论 (DFT) 的计算准确地预测了铁-57 Mössbauer 异构体在各种化学系统中的移位. 这一进步使无机,有机金属和金属蛋白化合物在各种旋转状态下能够精确地表征.
科学领域:
- 计算化学的计算化学
- 固态化学 固态化学
- 生物有机化学 生物有机化学
背景情况:
- 铁-57 Mössbauer光谱对于表征含铁化合物至关重要.
- 准确预测Mössbauer同位素移位 (delta(Fe)) 对于理解电子结构至关重要.
- 之前的计算方法在预测不同铁系统和旋转状态的delta ((Fe)) 方面存在局限性.
研究的目的:
- 为了报告密度函数理论 (DFT) 对铁-57的计算,Mössbauer 异构体移位 (delta(Fe)).
- 评估DFT方法对广泛的无机,有机金属和金属蛋白/金属氨酸系统的准确性.
- 在各种自旋状态中研究计算和实验德尔塔值之间的相关性.
主要方法:
- 对24个模型系统进行了密度函数理论 (DFT) 计算.
- 计算包括S = 0, 1/2, 1, 3/2, 2, 和 5/2旋转状态.
- 使用混合交换相关函数B3LYP,并与其他函数进行比较.
主要成果:
- 在计算和实验同位素转移之间达成了很好的一致性 (R(2) = 0.973-0.981).
- 平方根均值偏差很小 (0.07-0.08 mm s(-1)),占整个 delta (Fe) 范围的3-4%.
- 对于正常和中间旋转状态,DFT准确地复制了异构体移位,涵盖了从-0.90到1.44毫米秒秒-1的广泛范围.
结论:
- DFT方法,特别是使用B3LYP函数的方法,可以准确预测铁-57同位素的移位.
- 这项研究证明了DFT对各种铁化学环境和旋转状态的可靠性.
- 分子轨道分析揭示了铁核对电荷密度的关键贡献,与同位素移位良好相关.
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