Inverse problem of the field of a charge and point dipole moment

1999 ◽  
Vol 42 (7) ◽  
pp. 587-591 ◽  
Author(s):  
T. G. Mitrofanova ◽  
V. Ya. Épp
Keyword(s):  
Inverse Problem ◽  
Dipole Moment ◽  
Point Dipole ◽  
A Charge

The Electrostatic Moments of a Charge Distribution

1997 ◽  
Author(s):  
Philip Coppens
Keyword(s):  
Dipole Moment ◽  
Charge Distribution ◽  
Dipole Moments ◽  
Practical Importance ◽  
Diffraction Method ◽  
Quadrupole Moments ◽  
Charge Densities ◽  
Moment Vector ◽  
Experimental Values ◽  
A Charge

The moments of a charge distribution provide a concise summary of the nature of that distribution. They are suitable for quantitative comparison of experimental charge densities with theoretical results. As many of the moments can be obtained by spectroscopic and dielectric methods, the comparison between techniques can serve as a calibration of experimental and theoretical charge densities. Conversely, since the full charge density is not accessible by the other experimental methods, the comparison provides an interpretation of the results of the complementary physical techniques. The electrostatic moments are of practical importance, as they occur in the expressions for intermolecular interactions and the lattice energies of crystals. The first electrostatic moment from X-rays was obtained by Stewart (1970), who calculated the dipole moment of uracil from the least-squares valence-shell populations of each of the constituent atoms of the molecule. Stewart’s value of 4.0 ± 1.3 D had a large experimental uncertainty, but is nevertheless close to the later result of 4.16 ± 0.4 D (Kulakowska et al. 1974), obtained from capacitance measurements of a solution in dioxane. The diffraction method has the advantage that it gives not only the magnitude but also the direction of the dipole moment. Gas-phase microwave measurements are also capable of providing all three components of the dipole moment, but only the magnitude is obtained from dielectric solution measurements. We will use an example as illustration. The dipole moment vector for formamide has been determined both by diffraction and microwave spectroscopy. As the diffraction experiment measures a continuous charge distribution, the moments derived are defined in terms of the method used for space partitioning, and are not necessarily equal. Nevertheless, the results from different techniques agree quite well. A comprehensive review on molecular electric moments from X-ray diffraction data has been published by Spackman (1992). Spackman points out that despite a large number of determinations of molecular dipole moments and a few determinations of molecular quadrupole moments, it is not yet widely accepted that diffraction methods lead to valid experimental values of the electrostatic moments.

scholarly journals Lorentz transformation of a charge-current density and “relativistic polarization” of a moving current loop

2020 ◽  
Vol 35 (23) ◽  
pp. 2050135
Author(s):  
Alexander Kholmetskii ◽  
Oleg Missevitch ◽  
Tolga Yarman
Keyword(s):  
Electromagnetic Field ◽  
Dipole Moment ◽  
Electric Dipole ◽  
Physical Meaning ◽  
Classical Electrodynamics ◽  
Current Loop ◽  
Lorentz Transformations ◽  
Covariant Formulation ◽  
Magnetic Dipoles ◽  
A Charge

We show that the claim by Franklin (Int. J. Mod. Phys. A 35, 2050061 (2020)) with respect to the vanishing charge distribution over the perimeter of an electrically neutral moving current loop is erroneous and is based on a misinterpretation of physical meaning of Lorentz transformations. Moreover, we show that the development of nonvanishing electric dipole moment by a moving current loop (which we named as “relativistic polarization”) represents a direct implication of covariant formulation of classical electrodynamics of material media. In this respect, we analyze some subtle effects related to the motion of magnetic dipoles in an electromagnetic field and disclose their physical meaning.

A charge–charge flux–dipole flux decomposition of the dipole moment derivatives and infrared intensities of the AB3 (A=N, P; B=H, F) molecules

2005 ◽  
Vol 317 (1) ◽  
pp. 35-42 ◽  
Author(s):  
Paulo H. César ◽  
Sérgio H.D.M. Faria ◽  
João V. da Silva ◽  
R.L.A. Haiduke ◽  
Roy E. Bruns
Keyword(s):  
Dipole Moment ◽  
Infrared Intensities ◽  
Charge Flux ◽  
A Charge

scholarly journals The Effect of Remanent Magnetization on Aeromagnetic Interpretation

1957 ◽  
Vol 10 (4) ◽  
pp. 547 ◽  
Author(s):  
DJ Sutton ◽  
WG Mumme
Keyword(s):  
Magnetic Field ◽  
Dipole Moment ◽  
Line Source ◽  
Remanent Magnetization ◽  
Point Dipole ◽  
Earth’S Magnetic Field ◽  
Plane Normal ◽  
Earth's Magnetic Field

The interpretation of aeromagnetic maps when the source may be approximated to a point dipole or line of dipoles is considered for the general case in which the dipole moment is not necessarily parallel to the Earth's magnetic field. For the line of dipoles, it is shown that even in this general case the depth and location of the source can be found, and in addition the direction of the component of the dipole moment in a plane normal to the line source may be determined. If the K�nigsberger ratio for the rock constituting the source is large, this is approximately the direction of the remanent magnetization. Such information is important from a palaeomagnetic viewpoint. When the source approximates closely to a point dipole, it is not possible both to locate the source and determine the direction of the dipole moment from an analysis of the aeromagnetic map and the solution of the problem requires further information.

Electron and cation transport in fluid dimethyl ether: effects of density and temperature

1982 ◽  
Vol 60 (8) ◽  
pp. 1034-1043 ◽  
Author(s):  
Norman Gee ◽  
Gordon R. Freeman
Keyword(s):  
Dipole Moment ◽  
Dimethyl Ether ◽  
Ion Mobility ◽  
Inelastic Collisions ◽  
Localized States ◽  
Point Dipole ◽  
Density Control ◽  
Low Energy Electrons ◽  
Dense Vapor ◽  
Momentum Transfer Cross Section

The effect of molecular electric dipole moment D on charge transport in fluids was examined by measurement of electron and ion mobilities in dimethyl ether (D = 1.3 D) and comparing them with the behavior in hydrocarbons. The fluid density was varied continuously from that of the normal vapor to that of the normal liquid, passing through the critical region. The density normalized mobility nμe of electrons in dimethyl ether vapor at low densities is 30-fold smaller than that in propane, although for the cations nμ+ in the ether is only 1.4-fold smaller than that in the alkane. The permanent dipole moment of the ether dominates the scattering of low energy electrons but not that of cations. The electron momentum transfer cross section is roughly 33% larger than that predicted by the Altshuler point dipole model, and has a minimum at ~0.12 eV. The energy gained from the electric field is removed mainly through inelastic collisions, even in the thermal energy range.Molecular clustering decreases both electron and ion mobilities, but the effect on the former is much larger due to the greater change in reduced mass. The extent of electron quasilocalization in the dense vapor of dimethyl ether is four times greater than that in nonpolar hydrocarbons. Electrons form relatively stable localized states in the liquid at n/ne > 2.0. Ion mobility undergoes a transition from "density control" to "viscosity control" with increasing density in the low density liquid. Viscosity control is operative at n/ne > 2.4.

ANIONS AND ANOMALIES

2007 ◽  
Vol 22 (27) ◽  
pp. 4901-4910 ◽  
Author(s):  
M. BAWIN ◽  
SIDNEY A. COON ◽  
BARRY R. HOLSTEIN
Keyword(s):  
Dipole Moment ◽  
Dipole Moments ◽  
Finite Size ◽  
Binding Energies ◽  
Quantum Mechanical ◽  
Behavior Changes ◽  
Point Dipole ◽  
Long Distance ◽  
Distance Behavior ◽  
Static Point

We analyze the recent claim that experimental measurements of binding energies of dipole-bound anions can be understood in terms of a quantum mechanical anomaly. The discrepancy between the experimental critical dipole moments and that predicted by the anisotropic inverse square potential of a static dipole precludes such an explanation. As has long been known, in the physical problem one must include rotational structure so that the long distance behavior changes from 1/r2 to 1/r4. In a simple model this can be shown to lead to a modification of the critical dipole moment of 20% or so, bringing it into agreement with experiment. This, together with the fact that inclusion of finite size effects does not change the critical dipole moment of the static point dipole, strongly suggests that the quantum mechanical anomaly interpretation of the formation of dipole-bound anions cannot be correct.

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