Germanium-hydrogen-lithium center in α-quartz

Abstract

A new center, denoted by GeHLi2, has been observed by EPR to be present in alpha-quartz containing germanium, after room temperature x irradiation. The spin Hamiltonian at 8909 MHz and 300°K has been measured, yielding the Zeeman splitting tensor g and the hyperfine coupling tensors à (73Ge), à (1H), à (7Lii), and à (7Li2). From the principal values and axis directions, a model for the center of the form Ge3+H-(Li +)2 has been derived. This postulates germanium to be present substitutionally at a silicon site, with the hydride and two lithium ions occurring interstitially nearby. The unpaired electron is thought to be in a Ge orbital a(4s)+b(4p), with | a |2∼0.18 and | b | 2∼0.35, with considerable spin density also at the hydrogen. The center may be formed from a diamagnetic precursor Ge2+(Li +)2 by reaction with a hydrogen atom. Copyright © 1971 by the American Institute of Physics.