A new expression for the calculation of the solute dipole moment in the concentration range 1-40% at microwave frequencies

1988 ◽  
Vol 23 (4) ◽  
pp. 591-544
Author(s):  
G.K. Johri ◽  
G. Iernetti
Keyword(s):  
Dipole Moment ◽  
Microwave Frequencies

Dielectric Studies. Part XXXI. Analysis of the Dielectric Data of Phenol and its Polymerized Forms

1971 ◽  
Vol 49 (7) ◽  
pp. 1106-1114 ◽  
Author(s):  
M. D. Magee ◽  
S. Walker
Keyword(s):  
Dipole Moment ◽  
Relaxation Time ◽  
Mole Fraction ◽  
The State ◽  
Distribution Parameter ◽  
Dielectric Studies ◽  
Microwave Frequencies ◽  
Dielectric Absorption ◽  
Dielectric Data ◽  
Intramolecular Process

The dielectric absorption and dispersions of several solutions of phenol in p-xylene have been measured at four microwave frequencies and at 2 MHz at a temperature of 25 °C. The data have been analyzed in terms of a mean relaxation time, a distribution parameter, and an apparent dipole moment which are useful empirical parameters for assessing the state of aggregation of the phenol molecules. The relaxation time at the lowest practicable concentration (0.02 mole fraction) is long for a molecule expected to relax predominantly by an intramolecular process. This and the behavior of the relaxation time and apparent dipole moment with increasing concentration are considered in terms of a model based on progressive association into an extended series of multimers, the trimer having a zero (or low) dipole moment and higher multimers becoming increasingly flexible.

Dipole moment and dielectric relaxation studies in some azo compounds

1982 ◽  
Vol 60 (2) ◽  
pp. 257-260 ◽  
Author(s):  
P. B. K. Sarma ◽  
P. V. G. K. Murthy ◽  
C. R. K. Murty
Keyword(s):  
Dipole Moment ◽  
Solution Method ◽  
Dipole Moments ◽  
Relaxation Times ◽  
Azo Compounds ◽  
Dielectric Anisotropy ◽  
Dilute Solution ◽  
Microwave Frequencies ◽  
Central Group ◽  
Relaxation Studies

Dipole moments (μ) and relaxation times (τ) of seven azo central group liquid crystal compounds have been determined using the dilute solution method at radio and microwave frequencies. The results agree fairly well with the estimated values of the dipole moments. The angle, β, between the direction of the dipole moment and the long axis of the molecule, is determined for each molecule from structural considerations. The predicted sign of the dielectric anisotropy (Δε) from the estimated value of p is confirmed experimentally.

Molekülinterne Dipolorientierung und dielektrische Absorption in verdünnter Lösung bei Mikro-und Submillimeterwellen. IV.Chlormethyl-Verbindungen

1988 ◽  
Vol 43 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Gerhard Klages
Keyword(s):  
Dipole Moment ◽  
Dielectric Loss ◽  
Relaxation Times ◽  
Minor Role ◽  
Polar Group ◽  
Debye Relaxation ◽  
Microwave Frequencies ◽  
Aromatic Molecules ◽  
Perpendicular Component ◽  
Rotational Process

Abstract The dielectric loss of eight molecules with the polar group in aromatic bonds and three in aliphatic bonds has been measured in very dilute solutions of cyclohexane at 20 °C. The measurements have been made at microwave frequencies in the range 2 to 130 GHz and at five wave numbers in the range 8 to 85 cm-1 (generated by a pumped molecular laser). These measurements are supplemented using a Fourier transform spectrometre up to 300 cm-1. The dielectric loss spectra ε″(γ̄) have been separated into a number of absorption regions (three or four in the microwave area) using the two variable Mori formalism. The power absorption spectra α(γ̄) are fitted to the Lorentzian shapes in order to determine the FIR resonances.The dielectric dispersion step determined from loss measurements contains the contributions from all orientational processes of the permanent molecular dipole moment. The distribution of relaxation times indicates that the polar group reorientates by a fast intramolecular rotational process in five of the eight aromatic molecules investigated. Furthermore these five substances show character­istic broad resonance centred at approximately 39 cm-1. In order to determine the influence of the other substituted groups, the components of the dipole moment parallel and perpendicular to the internal axis of rotation are calculated from the dispersion steps. The perpendicular component does contribute as well to the Debye relaxation according to the Budo model as to the Poley and FIR absorptions. The relative magnitudes of these contributions are rather similar in the five molecules. In two other molecules, the intramolecular orientational process plays a relatively minor role due to the steric hindrance by a neighbouring group. However in dichloro-o-xylene, the two neighbour­ing groups do not prevent the fast process except that the net dipole moment is significantly reduced. Again, due to sterichindrance, the aliphatic bonded group molecules do not exhibit the fast dipolar orientational process or the characteristic resonance at 39 cm-1.

THE DIPOLE MOMENT INTERACTION OF BOUND EXCITONS IN HIGHLY EXCITED CdS

1985 ◽  
Vol 46 (C7) ◽  
pp. C7-221-C7-225
Author(s):  
Bao Qingcheng ◽  
Dai Rensong ◽  
Xu Xurong
Keyword(s):  
Dipole Moment ◽  
Moment Interaction
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