Direct calculation of the structural and spectral properties of chemical species occurring in minerals and in hydrothermal solutions will be performed using proven techniques from molecular quantum chemistry. For halide, oxide and sulfide complexes of 1st transition series metals the P.I.'s will calculate equilibrium structures, vibrational frequencies and electric field gradients. They will study both complexes existing in solution, such as aquated Zn(SH)n2-n, and molecular cluster models for species occurring in minerals, such as Fe(OH2)62+. One goal of the study will be to encourage the use of transition metal NMR within geochemistry. They will also calculate Mossbauer parameters (chemical isomer shift and electric field gradient) for Fe in various oxide and sulfide environments using conventional SCF methods. They will continue their studies of the electronic properties of sulfur containing ligands and their interaction with transition metals. They will also continue our studies of polarizabilities and NMR shieldings of oxidic molecules containing B, Al, Si and P. They plan to study polarizability anisotropies for less symmetric species and to more accurately include the influence of counterions. Similarly, studies of isotropic NMR shieldings for silicate species will be extended to study NMR anisotropies in lower symmetry environments. Finally, a series of experiments and theoretical studies will be completed for small ring systems.
