Dielectric anomalies in bismuth: Electronic relaxation times at far-infrared frequencies

1977 ◽  
Vol 26 (3-4) ◽  
pp. 423-438 ◽  
Author(s):  
Avid Kamgar ◽  
H. Schaber
Keyword(s):  
Relaxation Times ◽  
Far Infrared ◽  
Electronic Relaxation ◽  
Infrared Frequencies

Dynamic Nuclear Polarization Studies of TANOL/water-glycerol Solutions

2000 ◽  
Vol 55 (8) ◽  
pp. 682-686 ◽  
Author(s):  
İsmail Sert ◽  
M. Maral Sünnetçioǧlu ◽  
Rıza Sungur ◽  
Gökçe Bingöl
Keyword(s):  
Dynamic Nuclear Polarization ◽  
Nuclear Polarization ◽  
Relaxation Times ◽  
Electronic Relaxation ◽  
Coupling Constant ◽  
Constant Concentration ◽  
Low Field ◽  
Leakage Factor ◽  
Water Glycerol ◽  
Polarization Studies

Abstract Dynamic Nuclear Polarization (DNP) studies of TANOL/water-glycerol solutions were per-formed at 1.53 mT. The samples have either various water-glycerol ratios at constant concentration or various concentrations at a constant water-glycerol ratio. The low field EPR spectra were recorded, the DNP parameters(enhancement factors, coupling constant, leakage factor) were determined, electronic relaxation times were measured. Depending on the values obtained, the interactions between nuclei and electrons are discussed.

Dielectric Relaxation of Aliphatic Ethers in Dilute Solutions

1978 ◽  
Vol 33 (6) ◽  
pp. 687-692
Author(s):  
A. Hasan ◽  
G. Klages
Keyword(s):  
Dielectric Relaxation ◽  
Chain Length ◽  
High Frequency ◽  
Relaxation Times ◽  
High Mobility ◽  
Far Infrared ◽  
Chain Molecule ◽  
The Mean ◽  
Aliphatic Ethers ◽  
Main Region

Abstract Dielectric relaxation of nine primary aliphatic ethers - seven symmetric ethers of chain length C6 to C32, one asymmetric ether and one molecule with three ether groups in the chain - has been studied by loss measurements at 11 frequencies between 0.3 and 300 GHz in dilute cyclohexane and mesitylene solutions at 20°C. The absorption curves are shown not to be symmetrical. The main region has been analysed in terms of a symmetric distribution of relaxation times; the high frequency contribution due to the far infrared absorption was always less than 20%. Symmetric ethers show an increasing mean relaxation time and broadening of its distribution with increasing chain length. The spectra of cyclohexane solutions are found to contain additional short relaxation times. Compared with a, α, ω-dichlorides the mean relaxation times of symmetric ethers generally are shorter, which suggests a high mobility around C-O bonds becoming more effective in the unsymmetric ethers and even more so in the chain molecule with two methoxy end groups.

The Infrared Spectrum of Ethylene Oxide Clathrate Hydrate between 360 and 20 cm−1, at 100 °K

1972 ◽  
Vol 50 (21) ◽  
pp. 3443-3449 ◽  
Author(s):  
J. E. Bertie ◽  
D. A. Othen
Keyword(s):  
Hydrogen Bonds ◽  
Infrared Spectrum ◽  
Ethylene Oxide ◽  
Infrared Spectra ◽  
Far Infrared ◽  
Empirical Correlation ◽  
Strong Absorption ◽  
Water Molecules ◽  
Oxide Hydrate ◽  
Infrared Frequencies

The infrared spectra of authenticated samples of ethylene oxide hydrate and deuterate at 100 °K have been measured between 360 and 20 cm−1. The spectra confirm that the water molecules are orientationally-disordered and reorient slowly compared to far-infrared frequencies. An empirical correlation is suggested between the frequencies of strong absorption and the number of non-equivalent hydrogen bonds, their length and distribution. The contribution to the spectrum by the ethylene oxide intermolecular vibrations is discussed.

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