Studies in Mineral Surface Reactivity and Geochemistry to the Atomic Level

我们提出了一个雄心勃勃的矿物表面化学项目，该项目将在两个平行和互补的战线上进行。其中一个项目涉及研究矿物表面单个原子位的电子结构。另一个项目涉及多相氧化还原反应。将采用理论、实验和分析方法。包括扫描隧道显微镜、电子隧道光谱、扫描(原子力)显微镜、X射线和紫外光电子能谱、俄歇电子能谱和扫描俄歇显微镜、低能电子衍射和二次电子显微镜。这项研究的理论方面将主要涉及电子隧穿和表面的电子性质。第一部分的具体目标是a)计算赤铁矿、黄铁矿和方铅矿的“完美”和缺陷表面上单个原子的电子结构，b)使用这些信息来解释在真空和非真空环境中收集的隧道图像和光谱，以及c)将我们的发现与矿物表面“活性部位”的理论/推测联系起来。第二部分的目标是a)确定Mn(II)AQ在矿物表面被氧化的具体机制，b)确定痕量其他对环境重要的金属的影响，以及c)将我们的发现与其他涉及含水金属与氧化物相互作用的非均相氧化还原和非氧化还原体系联系起来。如果成功，我们的结果将适用于矿物表面化学的几乎所有方面。

We propose an ambitious mineral surface chemistry project that will proceed on two parallel and complementary fronts. One project deals with the study of the electronic structure of individual atomic sites on mineral surfaces. The other project deals with heterogeneous redox reactions. Theoretical, experimental, and analytic methods will be employed . Including scanning tunneling microscopy, electron tunneling spectroscopy, scanning (atomic) force microscopy, x-ray and ultraviolet photoelectron spectroscopies, Auger electron spectroscopy and scanning Auger microscopy, low energy electron diffraction, and secondary electron microscopy. Theoretical aspects of this study will deal primarily with electron tunneling and the electronic properties of surfaces. The specific objectives in Part I are a) to calculate the electronic structure of individual atoms on both "perfect" and defective surfaces of hematite, pyrite, and galena, b) to use this information to interpret tunneling images and spectra collected in vacuum and non-vacuum environments, and c) to relate our findings to theories/speculations on "reactive sites" on mineral surfaces. The objectives in Part II are a) to determine the specific mechanisms by which Mn(II)aq is oxidized on mineral surfaces, b) to determine the influence of trace amounts of other environmentally important metals, and c) to relate our findings to other heterogeneous redox and non-redox systems involving the interaction of aqueous metals on oxides. If successful, our results will be applicable to nearly every aspect of mineral surface chemistry.