Electron Spin Resonance of Hydrogen Atoms in CaF2

Abstract

We report the results of a detailed investigation of the electron spin resonance of a hydrogen atom in an interstitial position in CaF 2 . The following aspects of the problem are treated in detail: (1) apparatus and sample preparation; (2) a spin Hamiltonian with four parameters describing the g value and hfs of the hydrogen atom with the eight equivalent fluorine nuclei surrounding it; (3) the electron-nuclear double resonance (ENDOR) spectrum and the resonance linewidth; and (4) an attempt to calculate the parameters of the spin Hamiltonian starting from atomic and ionic wave functions. Our sample preparation technique has allowed us to deuterate the specimens, and we have obtained spin Hamiltonian parameters for the deuterium center as well. Most of the data were obtained at room temperature, but some data are available on the hydrogen center at 77°K. We have essayed an explanation of the small proton-deuteron and temperature-dependent differences of the spin Hamiltonian parameters.

Compensation of Trivalent Europium and Ytterbium Ions in Calcium Fluoride by Interstitial Hydride Ions

“…The Rare Earths were added to the melt as the oxide or fluoride in concentrations from 0.02 to 0.5 atyo. Samples typically 1 to 2 mm in thickness were cleaved from the as-grown crystals and treated with hydrogen or deuterium in the manner described by Hall and Schumacher [3]. After diffusion, the samples were ground and polished where necessary to remove surface damage prior to optical examination.…”

“…ion, in which case the symmetry of both ions is reduced to C4". Such It is now well known that a fraction of the F-ions in fluorite crystals may be replaced by H-ions by means of the diffusion process described by Hall and Schumacher [3]. It has also been shown that when trivalent ions are present in oxygen-free crystals, interstitial H-ions are introduced.…”

Optical properties of U centers in alkali halides and alkaline earth fluorides

“…Because the H -ion has a differe nt mass , polarizability, and interac tion with its neighborin g ions than has the anion which it replaces, th e U ce nter c hanges both the phonon spectrum and th e optical prope rties of its host crystal. Changes in th e phonon spectrum include ne w features at e nergies substantially greater than the energies df the optic phonons of the host lattice [1][2][3][4][5][6][7][8][9][10][11]. 1 Changes in the optical properties include a c harac teristi c electronic absorption band, the V band , in the ultraviole t region [12][13][14][15][16][17][18][19][20] and are the concerns of this paper.…”

ENDOR Investigations on Interstitial Hydrogen and Deuterium Atoms in SrF2 Crystals

“…The X-irradiation of these crystals produces hydrogen and deuterium atoms on interstitial and substitutional sites. The EPR spectra are well known (1 …”