On the Application of the Raman-Krishnan Theory to Dipole Moment Measurements by the Dilute Solution Method

1936 ◽  
Vol 58 (12) ◽  
pp. 2435-2438 ◽  
Author(s):  
H. O. Jenkins ◽  
S. H. Bauer
Keyword(s):  
Dipole Moment ◽  
Solution Method ◽  
Dilute Solution

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.

The dielectric constant of a liquid

1953 ◽  
Vol 6 (2) ◽  
pp. 93 ◽  
Author(s):  
AD Buckingham
Keyword(s):  
Dielectric Constant ◽  
Dipole Moment ◽  
Polar Solvent ◽  
Molecular Model ◽  
Principal Direction ◽  
Molecular Shape ◽  
Pure Liquid ◽  
Dilute Solution ◽  
Onsager Theory ◽  
Special Case

Some earlier theories in which attempts have been made to allow for the influence of molecular shape on the static dielectric constant of a liquid are shown to be inaccurate. A general equation is derived for the dielectric constant of a liquid, and this is then applied to a molecular model consisting, in the first instance, of an ellipsoid uniformly polarized in a principal direction, and secondly, to an optically anisotropic ellipsoid ; in both cases the surroundings are assumed to form a continuum. The results of this more general approach applied to several substances are more satisfactory than those obtained by the original Onsager theory. The theory is also applied to mixtures, and in the special case of a dilute solution in a non-polar solvent, the equation of Ross and Sack is obtained when the ellipsoid is isotropic. A correlation has been noted in the discrepancies found when the dipole moment of a substance is calculated by means of observations on the pure liquid and on dilute solutions in a non-polar solvent, using the equations derived in the present paper.

Mean-Square Electric Dipole Moment of Oligo- and Poly(methyl methacrylate)s in Dilute Solution

1997 ◽  
Vol 30 (20) ◽  
pp. 6199-6207 ◽  
Author(s):  
Hitoshi Ando ◽  
Takenao Yoshizaki ◽  
Akihiro Aoki ◽  
Hiromi Yamakawa
Keyword(s):  
Dipole Moment ◽  
Methyl Methacrylate ◽  
Electric Dipole Moment ◽  
Electric Dipole ◽  
Mean Square ◽  
Dilute Solution ◽  
Poly Methyl Methacrylate

π-Elektronen-Dipolmoment eines Pyridinium-N-phenol-betains

1966 ◽  
Vol 21 (9) ◽  
pp. 1373-1376 ◽  
Author(s):  
A. Schweig ◽  
C. Reichardt
Keyword(s):  
Dielectric Constant ◽  
Dipole Moment ◽  
Ground State ◽  
Dipole Moments ◽  
Saturated Hydrocarbon ◽  
Dilute Solution ◽  
Uniform Medium ◽  
Order Of Magnitude ◽  
Dimensional Electron Gas ◽  
Experimental Values

The ground state dipole moment of the π-electrons of 2.4.6-triphenyl-N- [3.5-di-tert-butyl-4-hydroxy-phenyl] -pyridinium-betain I, a highly solvatochromic substance, was determined by measuring the dielectric constant of a dilute solution and calculating first the dipole moment of the whole system (σ- and π-electrons) using the method of HALVERSTADT and KUMLER. The dipole moment of the π-electrons was then calculated, asuming the π-electron dipole to be imbedded in a spherical medium of dielectric constant 2. The value calculated by this method was compared with the π-electron dipole moment directly obtained from the dielectric constant of the dilute solution using a method of H. KUHN. This method is based on the assumption that a π-electron of a dissolved molecule sees the σ-electrons of the molecule and of the surrounding solvent, a saturated hydrocarbon, as a continuous uniform medium of dielectric constant 2. Thus the π-electron dipole of the solute molecule is regarded as being imbedded in a continuous medium of dielectric constant 2. It was found that the values of the π-electron dipole moments determined by the two methods agree well. Furthermore these experimental values agree with a theoretical value obtained in the case of N- [4-hydroxy-phenyl] -pyridinium-betain II using the one dimensional electron gas method including electron repulsion. The order of magnitude of the π-electron dipole moment of I clearly shows that the ground state of this molecule is highly polar.

Computer averaging of lattice images of poly-4-methyl-pentene-1 (P4mp1): Noise created artifacts

1987 ◽  
Vol 45 ◽  
pp. 388-389
Author(s):  
P. Pradère ◽  
J.F. Revol ◽  
R. St. John Manley
Keyword(s):  
Low Dose ◽  
Polymer Concentration ◽  
Processing System ◽  
Limiting Factor ◽  
Dilute Solution ◽  
New Techniques ◽  
Dose Unit ◽  
Lattice Images ◽  
Dose Imaging ◽  
Imaging Conditions

Although radiation damage is the limiting factor in HREM of polymers, new techniques based on low dose imaging at low magnification have permitted lattice images to be obtained from very radiation sensitive polymers such as polyethylene (PE). This paper describes the computer averaging of P4MP1 lattice images. P4MP1 is even more sensitive than PE (total end point dose of 27 C m-2 as compared to 100 C m-2 for PE at 120 kV). It does, however, have the advantage of forming flat crystals from dilute solution and no change in d-spacings is observed during irradiation.Crystals of P4MP1 were grown at 60°C in xylene (polymer concentration 0.05%). Electron microscopy was performed with a Philips EM 400 T microscope equipped with a Low Dose Unit and operated at 120 kV. Imaging conditions were the same as already described elsewhere. Enlarged micrographs were digitized and processed with the Spider image processing system.

Two-stage self-seeding method for preparation of single crystals of poly(phenylene sulfide)

1989 ◽  
Vol 47 ◽  
pp. 368-369
Author(s):  
Sengshiu Chung ◽  
Peggy Cebe
Keyword(s):  
Single Crystals ◽  
High Performance ◽  
Dilute Solution ◽  
Two Stage ◽  
Annealing Behavior ◽  
High Performance Polymers ◽  
Seeding Method ◽  
Phenylene Sulfide

We are studying the crystallization and annealing behavior of high performance polymers, like poly(p-pheny1ene sulfide) PPS, and poly-(etheretherketone), PEEK. Our purpose is to determine whether PPS, which is similar in many ways to PEEK, undergoes reorganization during annealing. In an effort to address the issue of reorganization, we are studying solution grown single crystals of PPS as model materials.Observation of solution grown PPS crystals has been reported. Even from dilute solution, embrionic spherulites and aggregates were formed. We observe that these morphologies result when solutions containing uncrystallized polymer are cooled. To obtain samples of uniform single crystals, we have used two-stage self seeding and solution replacement techniques.

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