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Electron Spin Resonance Studies of Light Sensitive Centers with Tetragonal Symmetry in CaO
Author(s) -
Boas J. F.
Publication year - 1986
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221380214
Subject(s) - tetragonal crystal system , electron paramagnetic resonance , center (category theory) , impurity , crystallite , ion , vacancy defect , crystallography , crystal (programming language) , symmetry (geometry) , materials science , atomic physics , chemistry , nuclear magnetic resonance , crystal structure , physics , organic chemistry , geometry , mathematics , computer science , programming language
Two centers with tetragonal symmetry and principal axes along 〈100〉 are observed by ESR in single crystals of CaO. The ESR signal intensity of both the centers is affected by visible light illumination. One center ( g ∥ = 2.0048, g ⟂ = 2.0007) occurs in highly colored crystals and may be associated with carbon impurities introduced during crystal growth. The other ( g ∥ = 1.99905, g ⟂ = 1.99956) occurs in “clear” crystals after 1 MeV electron irradiation and has the characteristics of an anion–cation vacancy pair center containing one electron (i.e. a P − or F c +center). The g ‐values do not agree with those found for the same center in polycrystalline CaO but are consistent with a simple model of a perturbed F + center.