Calculation of the effect of intrinsic point defects and volume swelling in the nuclear magnetic resonance spectra of ZrSiO4.

TL;DR: In this article, a variety of computational tools have been used to study the chemical properties of point defects in the crystalline phase of ZrSiO4, and their effect in its lattice parameters.

Abstract: A variety of computational tools have been used to study the chemical properties of point defects in the crystalline phase of ZrSiO4, and their effect in its lattice parameters. The experimental evidence of a large anisotropic volume swelling in natural and artificially irradiated samples of ZrSiO4 was used to select the subset of defects that give similar lattice swelling for the concentrations studied, namely interstitials of O and Si, and the anti-site Zr Si . Using the relaxed atomic structures, the nuclear magnetic resonance spectra were calculated by means of first principles density functional methods, in order to find additional evidence for the presence of high concentrations of some of these defects in irradiated zircon. The results obtained for the defects singled out before are still compatible with available experimental information. Our calculations also show that volume swelling in crystalline ZrSiO4 would produce a considerable displacement of the 17O and 91Zr chemical shifts towards highe...