Applications of High Resolution NMR to Geochemistry: Crystalline, Glass, and Molten Silicates

摘要

The nuclear spin interactions and the associated quantum mechanical dynamics which are present in solid state NMR are introduced. A brief overview of aluminosilicate structure is presented and crystalline structure is then reviewed, with emphasis on the contributions made by sup 29 Si NMR spectroscopy. The local structure of glass aluminosilicates as observed by NMR, is presented with analysis of the information content of sup 29 Si spectra. A high-temperature (to 1300 deg C) NMR spectroscopic investigation of the local environment and dynamics of molecular motion in molten aluminosilicates is described. A comparison is made of silicate liquid, glass, and crystalline local structure. The atomic and molecular motions present in a melt are investigated through relaxation time (T sub 1 and T sub 2 ) measurements as a function of composition and temperature for sup 23 Na and sup 29 Si. (ERA citation 11:020449)