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.
