Dynamics of supercooled liquid and plastic crystalline ethanol: Dielectric relaxation and AC nanocalorimetry distinguish structural α- and Debye relaxation processes

2017 ◽  
Vol 147 (1) ◽  
pp. 014502 ◽  
Author(s):  
Y. Z. Chua ◽  
A. R. Young-Gonzales ◽  
R. Richert ◽  
M. D. Ediger ◽  
C. Schick
Keyword(s):  
Dielectric Relaxation ◽  
Supercooled Liquid ◽  
Relaxation Processes ◽  
Debye Relaxation

Dielectric Relaxation Studies of the Fast Lithium-Ion Conductor La2/3-xLi3xTiO3 (x=0.06, 0.11)

2012 ◽  
Vol 457-458 ◽  
pp. 1019-1024
Author(s):  
Wei Guo Wang ◽  
Qian Feng Fang ◽  
Gang Ling Hao
Keyword(s):  
Dielectric Relaxation ◽  
Phonon Frequency ◽  
Lithium Ion ◽  
Relaxation Processes ◽  
Ion Diffusion ◽  
Lithium Ions ◽  
Debye Relaxation ◽  
Exponential Factor ◽  
Relaxation Parameters ◽  
Lithium Ion Diffusion

The diffusion processes of lithium ions in La2/3-xLi3xTiO3 (x=0.06, 0.11) compounds were investigated by dielectric relaxation method. Prominent relaxation dielectric loss peaks, peaks P1 and P2 in La0.56Li0.33TiO3 and peaks P3 and P4 in La0.61Li0.18 TiO3, were observed. From the shift of peak position with frequency, the activation energy of 0.36~0.42 eV and the pre-exponential factor of relaxation time in the order of 10-14 ~ 10-13 s were obtained if one assumes Debye relaxation processes. The activation energies of lithium ion diffusion in La2/3-xLi3xTiO3 compounds and the characteristic vibration frequency for the ionic hopping motion are higher than those measured by 7Li nuclear magnetic resonance (NMR) spectroscopy and that of the typical phonon frequency (about 1013Hz). These values of relaxation parameters strongly suggest the existence of interaction between the relaxation species (here lithium ions or vacancies). Basing on the coupling model, the decoupled relaxation parameters of the dielectric relaxation peaks is: P1 (0.14 eV, 2×10-13 s), P2 (0.25 eV, 1.8×10-13 s), P3 (0.17 eV, 4×10-13 s) and P4 (0.3 eV, 2.7×10-13 s). These decoupled parameters are very close to the NMR measurement results and the reciprocal of the typical phonon frequency. Judging from the relaxation parameter of the peaks and combining with the crystallographic characterization, it is suggested that the P1 (P3) and P2 (P4) peaks are associated with the lithium ion diffusion in the ab planes and between the adjacent ab planes, respectively.

Relaxation processes of some simple aliphatic molecules in dilute solutions

1977 ◽  
Vol 55 (4) ◽  
pp. 297-301 ◽  
Author(s):  
M. P. Madan
Keyword(s):  
Carbon Tetrachloride ◽  
Dielectric Relaxation ◽  
Thermodynamic Parameters ◽  
Relaxation Times ◽  
Relaxation Processes ◽  
Dilute Solutions ◽  
Microwave Region ◽  
Nonpolar Solvents ◽  
Dielectric Data ◽  
Intramolecular Rotation

The dielectric relaxation processes of acetone, cyclohexanone, 4-methyl-2-pentanone, and 4-heptanone in dilute nonpolar solvents, n-heptane, cyclohexane, benzene, and carbon tetrachloride have been studied in the microwave region over a temperature range 10 to 60 °C. The relaxation times and the thermodynamic parameters for the activated states have been determined using the measured dielectric data. The results have been discussed in terms of dipole reorientation by molecular and intramolecular rotation and compared, wherever possible, with other similar studies on aliphatic molecules.

EFFECT OF CELL THICKNESS ON THE DIELECTRIC RELAXATION PROCESSES IN FERROELECTRIC LIQUID CRYSTALS

2008 ◽  
Vol 22 (14) ◽  
pp. 2263-2273 ◽  
Author(s):  
RAJBIR SINGH ◽  
K. K. RAINA
Keyword(s):  
Liquid Crystal ◽  
Dielectric Relaxation ◽  
Dielectric Strength ◽  
Relaxation Processes ◽  
Goldstone Mode ◽  
Ferroelectric Liquid Crystal ◽  
Dielectric Relaxation Spectroscopy ◽  
Dielectric Parameters ◽  
Liquid Crystal Material ◽  
Cell Thickness

Dielectric relaxation spectroscopy in the frequency range 50 Hz to 1 MHz has been carried out in a room temperature ferroelectric liquid crystal mixture in the SmC*, SmA and N* phases in cells of different thickness. The relaxation frequency fr, distribution parameter α and dielectric strength δ∊ have been evaluated. Goldstone mode, domain mode and soft mode have been observed. It is found that the cell thickness has a significant effect on the dielectric parameters of the ferroelectric liquid crystal material. The results have been discussed.

On the temperature and pressure dependence of dielectric relaxation processes in ionic liquids

2021 ◽  
Author(s):  
Florian Pabst ◽  
Zaneta Wojnarowska ◽  
Marian Paluch ◽  
Thomas Blochowicz
Keyword(s):  
Ionic Liquids ◽  
Dielectric Relaxation ◽  
Pressure Dependence ◽  
Dynamic Processes ◽  
Relaxation Processes ◽  
Dielectric Spectra ◽  
Temperature And Pressure ◽  
Microscopic Origin

The temperature and pressure dependence of two dynamic processes in the dielectric spectra of five supercooled ionic liquids equipped with octyl-chains are reported. The microscopic origin of these processes is discussed.

Modeling of Dielectric Relaxation Processes in Moist Sand Rocks

2017 ◽  
Vol 60 (4) ◽  
pp. 711-716 ◽  
Author(s):  
P. P. Bobrov ◽  
V. N. Krasnoukhova ◽  
E. S. Kroshka ◽  
A. S. Lapina
Keyword(s):  
Dielectric Relaxation ◽  
Relaxation Processes ◽  
Moist Sand
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