Publication

Structure and hyperfine parameters of E'(1) centers in a-quartz and in vitreous SiO2

Alfredo Pasquarello
1997
Journal Articles

Abstract

We report a first-principle study of the E(1) defect in alpha-quartz and of the analogous E'(gamma) defect in amorphous SiO2. Our calculation supports the attribution of both these defects to a positively charged oxygen vacancy. The ground-state configuration of these defects is characterized by a large local relaxation of the atomic network, which leads to a localization of the unpaired electron on a Si dangling bond. Using the calculated electronic spin densities, we fully characterize the hyperfine interactions with nearby Si-29. Our results explain well both the strong and the weak features that are observed in the experimental spectra.

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https://infoscience.epfl.ch/entities/publication/5a758375-9737-4fd2-9442-ab4c5cb40b55

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Alfredo Pasquarello
1997
Journal Articles

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/5a758375-9737-4fd2-9442-ab4c5cb40b55

About this result

Related concepts (32)

Hyperfine structure

In atomic physics, hyperfine structure is defined by small shifts in otherwise degenerate energy levels and the resulting splittings in those energy levels of atoms, molecules, and ions, due to electromagnetic multipole interaction between the nucleus and electron clouds. In atoms, hyperfine structure arises from the energy of the nuclear magnetic dipole moment interacting with the magnetic field generated by the electrons and the energy of the nuclear electric quadrupole moment in the electric field gradient due to the distribution of charge within the atom.

Electron paramagnetic resonance

Electron paramagnetic resonance (EPR) or electron spin resonance (ESR) spectroscopy is a method for studying materials that have unpaired electrons. The basic concepts of EPR are analogous to those of nuclear magnetic resonance (NMR), but the spins excited are those of the electrons instead of the atomic nuclei. EPR spectroscopy is particularly useful for studying metal complexes and organic radicals. EPR was first observed in Kazan State University by Soviet physicist Yevgeny Zavoisky in 1944, and was developed independently at the same time by Brebis Bleaney at the University of Oxford.

Electron configuration

In atomic physics and quantum chemistry, the electron configuration is the distribution of electrons of an atom or molecule (or other physical structure) in atomic or molecular orbitals. For example, the electron configuration of the neon atom is 1s2 2s2 2p6, meaning that the 1s, 2s and 2p subshells are occupied by 2, 2 and 6 electrons respectively. Electronic configurations describe each electron as moving independently in an orbital, in an average field created by all other orbitals.

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Structure and hyperfine parameters of E'(1) centers in a-quartz and in vitreous SiO2

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