EPR study of Fe3+ in α-quartz: A reexamination of the so-called/center

Abstract

10 GHz electron paramagnetic resonance studies of Fe3+ in synthetic brown α-quartz single crystals have been carried out at 295 and at 40 K. The spin-Hamiltonian parameters were determined including high-spin Zeeman terms of form BS3 and allowing (g,D) matrix noncoaxiality as well as nonuniaxial anisotropy of the g matrix. Evaluation of the results, in part using the pseudosymmetry technique of Michoulier and Gaite, suggests that the so-called interstitial model (I center) is incorrect, and that the Fe 3+ ions in fact occur substitutionally at Si4+ sites. The new label [FeO4]- is proposed for the center. © 1986 American Institute of Physics.