Year: 1992
Type: article
Abstract: The centre (TiO 4 ) - , formed by X-irradiation at 77 K in naturally occurring crystalline rose quartz, has been studied by single-crystal electron paramagnetic resonance (EPR) spectroscopy. Here the central 3d 1 Ti 3+ ion exists within a slightly distorted oxygen tetrahedron. The hyperfine matrix of the low-abundance isotope 49 Ti was measured at 8 K and the g matrix was measured at several temperatures from 30 K down to 4 K The analysis of be spin-population distribution within the centre showed that the unpaired spin is almost entirely in the Ti 3d orbital mod 3z 2 -r 2 ). Estimates of the spin-lattice relaxation time T 1 and of the EPR linewidth in be temperature range 4-30 K were also obtained. T 1 decreases exponentially with increasing temperature, presumably owing to phonon coupling to the low-lying excited state mod xy) which is 8.1 meV (65 cm -1 ) above the ground state, via an Orbach process. At temperatures above approximately 15 K the abnormally large EPR linewidth is predominantly caused by lifetime broadening through T 1 . The near degeneracy of mod 3z 2 -r 2 ) and mod xy) indicate that (TiO 4 ) - has almost tetrahedral symmetry.
Authors: P Bailey, T Pawlik, H Sothe, J -M Spaeth, J Weil
Institution: University of Saskatchewan
Language: English
Subfield: Biophysics
Domain: Life Sciences
Open Access status: bronze
OpenAlex ID: W1971488583