A computational investigation of 17O quadrupolar coupling parameters and structure in [formula omitted]-quartz phase [formula omitted

Abstract

Ab initio band-structure calculations based on density functional theory have been completed for α -quartz phase GeO 2 to obtain electric-field gradients (efg) for oxygen atoms, including those for GeO 2 at elevated pressure and temperature. To interpret the resulting efg values and examine correlations between structure and 17O quadrupolar coupling parameters, additional ab initio self-consistent Hartree-Fock molecular orbital calculations were completed. The quadrupolar coupling constant was found to have a strong dependence on Ge–O distance and ∠ Ge – O – Ge , with the quadrupolar asymmetry parameter being primarily dependent on ∠ Ge – O – Ge . Analytical expressions describing these dependencies consistent with earlier investigations of analogous silicate compounds are also reported.