RUI: Collaborative Research: Improvements in the Application of the Mossbauer Effect to Studies of Minerals

提出了一套Moessbauer光谱实验，旨在真正量化矿物中的Fe3+和Fe2+含量。将确定将峰面积与物种丰度联系起来的价态和特定地点的无反冲分数“修正”系数，将在一组具有岩石学重要性的矿物上测试四个可用于处理Moessbauer数据的商用软件包，并将通过一套旨在展示新技术能力的三个两年制学生项目来突出现代仪器和建模的能力。该项目的学术价值有四个方面：(1)改进了对广泛矿物的Moessbauer分析，(2)了解了铁在辉石中的分布，辉石是所有地球上常见的造岩矿物，(3)首次能够分析长石中铁的氧化还原状态，以及(4)在必要的、严格约束的岩石学框架内研究了一种重要的变质矿物--绿泥石。这项研究的更广泛影响将是世界范围内在解释矿物学研究的Moessbauer光谱结果方面的改进。未来用穆斯堡尔光谱学研究矿物中铁的误差将被有效地降低，并将证明这项技术具有新的能力，即使在微小的样品或含铁量较低的样品中也可以用于地质材料的研究。该项目将对六名女本科生(每年两名)产生巨大的教育影响，她们将把这些项目作为高级论文的主题。

A set of Moessbauer spectroscopy experiments are proposed, designed to enable true quantification of Fe3+ and Fe2+ contents in minerals. Valence state- and site-specific recoil-free fraction "correction" factors for relating peak areas to species abundance will be determined, four commercially-available software packages for processing of Moessbauer data will be tested on a set of petrologically-important minerals, and the capabilities of modern instrumentation and modeling will be highlighted through a set of three, two-year student projects designed to demonstrate the abilities of the new technique. The intellectual merit of this project of this project has four aspects: (1) improvement of Moessbauer analyses of wide range of minerals, (2) understanding iron distribution in pyroxene, which is a common rock-forming mineral on all terrestrial planets, (3) enabling for the first time analyses of the redox state of iron in feldspars, and (4) study of an important metamorphic mineral, chlorite, within the necessary, well-constrained petrologic framework. The broader impact of this research will be worldwide improvements in interpreting Moessbauer spectroscopic results from mineralogical studies. The error bars on future studies of iron in minerals using Moessbauer spectroscopy will be effectively reduced, and it will be demonstrated that this technique has new capabilities that can be used to study geologic materials even in tiny samples or those with a low percentage of iron. This project will have great educational impact on the six women undergraduates (two each year) who will make these projects the topics of senior theses.