Temperature dependence investigation of the electron paramagnetic resonance of the photorefractive polymer BisA-NAS:DEH

1996 ◽  
Author(s):  
Abdalla M. Darwish ◽  
Nickolai V. Kukhtarev ◽  
Robert R. Copeland ◽  
R. Sliz ◽  
Putcha Venkateswarlu ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Temperature Dependence ◽  
Paramagnetic Resonance ◽  
Photorefractive Polymer ◽  
Electron Paramagnetic

Temperature dependence on the electron paramagnetic resonance spectra of natural jasper from Taroko Gorge (Taiwan)

2009 ◽  
Vol 37 (4) ◽  
pp. 201-208 ◽  
Author(s):  
G. N. Hemantha Kumar ◽  
G. Parthasarathy ◽  
R. P. S. Chakradhar ◽  
J. Lakshmana Rao ◽  
Y. C. Ratnakaram
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Temperature Dependence ◽  
Paramagnetic Resonance ◽  
Electron Paramagnetic

An Electron Paramagnetic Resonance Investigation of Iron-Indium Pairs in Silicon

1989 ◽  
Vol 163 ◽  
Author(s):  
P. Emanuelsson ◽  
W. Gehlhoff ◽  
P. Omling ◽  
H. G. Grimmeiss
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Temperature Dependence ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Paramagnetic Resonance ◽  
Field Splitting ◽  
Resonance Investigation ◽  
Electron Paramagnetic Resonance Investigation ◽  
Electron Paramagnetic

AbstractThree different Electron Paramagnetic Resonance (EPR) signals, one trigonal and two orthorhombic, which originates from iron-indium pairs in silicon are investigated. It is shown that the two orthorhombic spectra can be explained as transitions within the two doublets of a S=3/2 system with a large zero-field splitting. The temperature dependence of-the intensities reveals that the newly discovered spectrum corresponds to the lower doublet and that the zero-field splitting is 9.8 ± 2.0 cm-1.

Electron paramagnetic resonance and in situ photosensitivity investigation of the photorefractive polymer BisA-NAS:DEH

1995 ◽  
Author(s):  
Abdalla M. Darwish ◽  
Nickolai V. Kukhtarev ◽  
Robert R. Copeland ◽  
R. Sliz ◽  
Putcha Venkateswarlu ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Paramagnetic Resonance ◽  
Photorefractive Polymer ◽  
Electron Paramagnetic

An Electrolytically Generated, Localized Hole Center in Quartz

1989 ◽  
Vol 44 (4) ◽  
pp. 278-282
Author(s):  
A. B. Vassilikou-Dova ◽  
K. Eftaxias ◽  
G. Lehmann
Keyword(s):  
Activation Energy ◽  
Electron Paramagnetic Resonance ◽  
Temperature Dependence ◽  
Free Electron ◽  
Room Temperature ◽  
Hole Center ◽  
Paramagnetic Resonance ◽  
Tentative Model ◽  
Hyperfine Splittings ◽  
Electron Paramagnetic

Abstract In natural smoky quartz and neutron-irradiated, initially colorless quartz a new hole center was formed electrolytically at temperatures near 1100 K in addition to the well-known smoky quartz center. Unlike the latter its electron paramagnetic resonance spectra can already be measured at room temperature due to firm localization of the hole on one oxygen. It is characterized by fairly small hyperfine splittings due to Al impurity and significant deviations of all three principal g factors from that of a free electron. A tentative model for the structure of this center is proposed.An activation energy of 215 kJ/mol was determined for this electrolytic coloration from the temperature dependence of the electrolysis currents.

ALICYCLIC KETYLS: II. TEMPERATURE DEPENDENCE OF THE CONFORMATIONAL MOBILITY OF MEDIUM-SIZED RINGS

1965 ◽  
Vol 43 (12) ◽  
pp. 3294-3303 ◽  
Author(s):  
J. W. Lown
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Temperature Dependence ◽  
Room Temperature ◽  
Close Agreement ◽  
Conformational Equilibrium ◽  
Dihedral Angles ◽  
Paramagnetic Resonance ◽  
Conformational Equilibria ◽  
Electron Paramagnetic ◽  
Hyperfine Couplings

The electron paramagnetic resonance spectra of ketyls derived from alicyclic ketones containing from 6 to 12 carbons have been recorded in 1,2-dimethoxyethane or dimethoxymethane at temperatures from −96 to +87 °C. At −96° individual conformers of the cyclohexyl ketyl are observed with hyperfine couplings in close agreement with that of the conformationally 'frozen' 4-tert-butyl analogue at room temperature. The cycloheptyl ketyl conformational equilibrium between forms which have a plane of symmetry through the C—O bond axis is 'frozen' with respect to the spectrometer frequency at temperatures from −40 to +88 °C. Cyclooctyl ketyl equilibrates at ordinary temperatures between two conformers lacking a plane of symmetry through the C—O bond axis. The electron paramagnetic resonance spectra of the ketyls derived from 10- and 12-membered rings show dramatic temperature dependence, which is interpreted in terms of two or more simultaneous conformational equilibria. Values for the dihedral angles of the alpha protons and for the spin density on the sp2 carbon are derived.

Electron Paramagnetic Resonance of Shallow Phosphorous Centers in 4H- and 6H-SiC

2005 ◽  
Vol 483-485 ◽  
pp. 515-518 ◽  
Author(s):  
Nguyen Tien Son ◽  
Anne Henry ◽  
Junichi Isoya ◽  
Erik Janzén
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Temperature Dependence ◽  
Chemical Vapour Deposition ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Epr Spectrum ◽  
Paramagnetic Resonance ◽  
Hyperfine Constants ◽  
Cvd Growth ◽  
Electron Paramagnetic

Electron paramagnetic resonance (EPR) was used to study 4H- and 6H-SiC doped with P during chemical vapour deposition (CVD) growth. In 6H-SiC, three spectra with C3v symmetry and spin S=1/2, labelled Ph, Pc1 and Pc2, were detected. The g-values and the 31P hyperfine (hf) constants were determined for Ph: g||=2.0046, g^=2.0028, and A||=0.103 mT, A^<0.05 mT; for Pc1: g||=2.0039, g^=2.0025, and A||=0.615 mT, A^=0.43 mT; for Pc2: g||=2.0038(5), g^=2.0025, and A||=0.40 mT, A^=0.22 mT. The hf interaction with nearest 13C neighbours were also observed for the Pc1 and Pc2 centers, confirming that in CVD grown material the shallow P donor occupies the Si site. The Ph, Pc1 and Pc2 centers are assigned to the ground states of the shallow P at the hexagonal (Ph) and quasi-cubic sites (Pc1 and Pc2) in 6H-SiC. In 4H-SiC, an EPR spectrum of C3v symmetry with a larger anisotropy in the g-values (g||=2.0065 and g^=2.0006) was observed. The temperature dependence of the spectrum is similar to that of Ph in the 6H polytype. Its 31P hyperfine constants are determined as A||=0.294 mT and A^=0.21 mT.

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