E' CENTER IN GLASSY SIO2 - O-17, H-1, AND VERY WEAK SI-29 SUPERHYPERFINE STRUCTURE
E' CENTER IN GLASSY SIO2 - O-17, H-1, AND VERY WEAK SI-29 SUPERHYPERFINE STRUCTURE
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DOI：
10.1103/physrevb.22.4192
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发表时间：
1980-01-01
影响因子：
3.7
通讯作者：
GRISCOM, DL
中科院分区：
文献类型：
--
作者：
GRISCOM, DL
Electron-spin-resonance spectra have been obtained at 9.1 and 35 GHz for E′ centers induced by γ irradiation in a number of high-purity commercial fused silicas and in a suite of glassy Si O 2 samples of varying degrees of enrichment (or depletion) in the magnetic isotopes O 17 and Si 29. Computer simulation of the spectra of the O 17-enriched samples indicates the existence of a weak superhyperfine (shf) interaction (a meas a atomic≈ 5× 10− 4) with oxygens in three chemically equivalent near-neighbor sites." Weak" shf structure characterized by a≈ 8 G observed in samples containing≤ 50 at.% Si 29 is shown to be due to protons present as impurities. An unresolved broadening of the spectra of samples containing≥ 50 at.% Si 29 is ascribed to" very weak" shf interactions with next-nearest-neighbor silicons. These findings, together with a comparison of the g matrices of bulk and surface E′ centers, support the notion that the structure of the E′ center in glassy silica is essentially identical to that in α quartz; ie, both comprise asymmetrically relaxed oxygen vacancy defects.
