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One of the polarization errors encountered in the direction finding of atmospherics is produced by the effect of the Earth's magnetic field which is discussed in detail in paper I. Another error, the effect of the atmospherics origin, that is, the polarization error due to an inclined electric dipole such as a cloud discharge is discussed in this paper. The polarization error for ELF waves due to source inclination is small. That for VLF band by inclined electric dipole depends on the inclination of the dipole, height of the dipole, configuration between the dipole and the observing station and the conductivities of the ionosphere and the ground. If the direction finding could be operated at a frequency in the ELF range, there would be another merit in view of the cause of the polarization error.

In this paper (the first of a series), we present a general analysis of the parity violating phenomena induced by neutral currents in Atomic Physics. We first give expressions for the short range parity violating electron-nucleus and electron-electron potentials predicted by the theoretical schemes of weak interactions featuring neutral currents. We turn next to a detailed computation of the matrix element, between one-particle s and p states, of the electron-nucleus parity violating potential. Using a non-trivial extension of a method used by Foldy to put on a more rigorous basis a formula of Fermi and Segre giving the wave function of an s valence electron at the nucleus, we arrive at a remarkably simple expression, in terms of the binding energies, with a small correcting term involving the interpolated quantum defect and the potential of the electronic cloud at the origin. Arguments are given which lead us to believe that the accuracy of our formula is comparable to that of the Fermi-Segre formula, i. e. a few per cent when Z >> 1. Besides its simplicity, a remarkable feature of our result is a Z3 dependence, which obviously favours heavy atoms. We give a brief analysis of the manifestation of parity mixing in atomic radiative transitions, with a particular emphasis on the implications of time reversal invariance, which is preserved by the interactions discussed in this paper. In order to improve the existing limits, we suggest looking for parity violating effects in twice forbidden magnetic dipole transitions induced by a tunable laser beam in heavy atoms. In a typical case, like the 6 S1/2 → 7 S1/2 transition in atomic Cesium, a circular dichroism of the order of 10-4 is predicted. Finally we discuss the apparently more remote possibilities offered by the muonic atoms.

The derivation of the classical relativistic equations of motion for electric and magnetic dipole atoms or molecules in an external electromagnetic field of force, given in two previous papers (I and II), is extended in the present paper to the case that these atoms possess also electric quadrupole moments. Again Moller's equations of motion for relativistic systems with an internal angular momentum are taken as the starting point. We only consider the form of these equations in which the term describing the unphysical trembling motion of the atoms is eliminated (see paper II). The resulting equations of motion are used in order to derive the relativistic atomic energy-momentum tensor for a system, consisting of a (large) number of these atoms. It is found that the field part of this tensor is not of the same form as in the pure dipole case and also no longer expressible only in terms of quantities appearing in the atomic field equations.

In previous papers we developed techniques for the accurate calculation of dipole moments using moderate‐sized (200 configuration) CI calculations. In this paper we consider the modifications necessary to treat higher excited states of a symmetry. It is shown that states below the state of interest must be considered simultaneously to a similar degree of accuracy. Calculations were performed on the 2Σ+ states of CN. For the X 2Σ+ state the SCF, CI, and experimental dipole moments (in debye) are 2.301, 1.465, and 1.45±0.08; for B 2Σ+ the CI and experimental values are −0.958 and −1.15±0.08. Spin hyperfine constants, and in particular spin density at the nucleus, are considered in the context of one‐electron operator properties which may be calculated by the same methods used for the dipole moment. SCF and CI values for the spin density are compared with experimental values for several diatomic molecules.

The paper gives an elementary and popular account of some atomic and molecular concepts which are necessary for the formation of a model that will give a rational description of certain behaviour of dielectrics. It opens by explaining that the dielectric constant of many materials is found to depend on the radius of the molecule, and that the phenomenon of permittivity can be included in the inverse-square law of force between charges if the molecules can be supposed to exhibit an effect equivalent to that of electrostatic induction. An outline is then given of the Bohr atom and the electronic theory of valency, and this provides a mechanism equivalent to induction: It also provides a mechanism whereby it is to be expected that certain molecules possess a permanent electric moment, and moreover direct experiment shows that these molecules are electric dipoles. It then attempts a very graphic description of the manner in which dipoles must produce heat when the dielectric is in an alternating electric field. It closes with a brief description of certain experiments which have been made and designed to show that molecular dipoles are a cause of dielectric losses, and a brief discussion of whether they are the main cause of the losses experienced in the insulating materials commonly used in electrotechnology. The paper is intended to be read in conjunction with Dr. H. Frohlich's paper entitled "Theory of Dielectric Constant and Energy Loss in Solids and Liquids,"† and has been written to stimulate the interest of electrical engineers in certain molecular concepts which it seems possible may soon become necessary to use freely on practical everyday problems of electrotechnical construction.

We consider the problem of the approximate determination of the electromagnetic field generated by two oscillating electric dipoles in the center of a spherical cavity imbedded in a nonlinear plasma. The influence of the nonlinearities of the plasma upon the field are investigated by means of a perturbative solution of the relevant equations, deduced from the ‘quasi-hydrodynamic’ approach. Analytical and numerical results, which illustrate several nonlinear effects, as well as the influence of the rarefaction and ionization of the gas, are included. The main result of the paper is the prediction of an observable second harmonic field.

A five-parameter solution of the combined Einstein-Maxwell equations is given which describes a source containing mass, electric charge, magnetic dipole, higher multipole moments of all three kinds, and angular momentum. The solution is obtained by using Kinnersley's method of generating stationary Einstein- Maxwell fields from known solutions of the Einstein-Maxwell equations. We start with a two-parameter solution of a system having mass and a magnetic dipole moment discovered by Misra, Pandey, Srivastava, and Tripathi. All solutions discussed in this paper are asymptotically flat, and all have infinite red-shift surfaces that are singular. Possible relevance of these solutions to black-hole physics is remarkable upon. (auth)

The polarisation of Raman lines of sulphur and phosphorus is investigated with reference to their molecular structures. An intense Raman spectrum of liquid phosphorus has yielded three lines the state of polarisation of which conforms to the Raman-active vibrations of a tetrahedral molecule. The molecule of sulphur is considered to be a symmetrical puckered ring made up of two squares of four atoms each, one square placed at 45° with respect to the other. To explain the strong infra-red absorptions, the neighbouring atoms in the plane of each square are assumed to be connected with co-ordination bonds which give rise to electric dipoles causing absorption. The two lines 470 and 216 which are well-polarised are assigned to two symmetrical oscillations of such a model, 470 to the vibration in which the four atoms in each square move towards or away from the centre of the square and 216 to the vibration in which the two squares move towards or away from each other. The lines at 150 and 434 are completely depolarised and belong to anti-symmetric vibrations. The well-known changes of sulphur on heating are explained on the basis of this new molecular structure. A method of distilling high-boiling-point substances is also described in the paper.

It has been conclusively proved in the last two years that there is a significant effect of the solvent on the measured value of dipole moment of a solute. It has also been shown that the effect is mainly determined by the dielectric constant of the medium, suggesting a relatively simple physical cause, but the precise law of relationship is still disputed. A list of the formulae which had been proposed at the time of the Faraday Society's discussion is collated by Goss. These all have the status of empirical formulae, since that of Raman and Krishnan contains two difficult accessible constants. The theory formula of Weigle is omitted from this list. It receives some discussion in the next section of this paper. These formulae agree in disregarding the properties of the solute, excepting its dipole moment. The solvent effect is considered to be proportionately the same for all polar substances. Müller makes an exception in suggesting a modified law for certain substances, mainly ketones. The hydrogen halides, with positive solvent effects, are considered entirely anomalous, and their increase of moment is attributed to an intramolecular change towards more ionic linkage.

The fact that a magnetic dipole μ moving with velocity βc has an electric dipole moment p = β×μ/c has made periodic appearance in the literature but the importance of this fact and its general utility have not been given sufficient expression. It is the purpose of this paper to show how to derive the equation p=β×/c and then to use it for a simple description of the atomic spin-orbit interaction.

Morphic effects are effects induced in a crystal by the lowering of its symmetry through the application of a generalized external force. In this paper we study the effects of static electric fields and of strains on the frequencies of localized vibration modes associated with substitutional impurity atoms in homo-polar crystals. It is shown that the splitting of the triple degeneracy of such modes when the impurity is at a site of cubic symmetry by the application of these generalized forces can yield information about the anharmonic forces, electric dipole moment, and electronic polarizability associated with the impurity atom.

The method of solving the Thomas-Fermi equation, developed in a previous paper 1), is applied to the H2O-molecule. The electronic density is calculated. A proof is given that the Thomas-Fermi method, or generally any method, which treats the electrons as a continuous cloud of electricity obeying the Poisson equation, gives a zero value for the electric dipole moment of any molecule. © 1955 Stiching Physica, Amsterdam, Nederland.

In this paper the electric fields of an infinitesimal dipole oscillating in a hot plasma are derived in the absence of an external magnetic field; explicit expressions are obtained by making an approximation on the background electron velocity distribution function. These results are applied to investigate the resonance observed at the plasma frequency, and to estimate the radiation resistance of the dipole.

This paper describes a new method of radiofrequency spectroscopy in which transitions between the energy levels of a single rotational state of a linear rotator in an electric field are caused by a superimposed radiofrequency field. The method utilizes a molecular beam and has been applied to the measurement of the moment of inertia, $I$, and the electric dipole moment, $\ensuremath{\mu}$, of CsF. Values for these quantities are: $I=(187\ifmmode\pm\else\textpm\fi{}22){10}^{\ensuremath{-}40}$ g ${\mathrm{cm}}^{2}$ and $\ensuremath{\mu}=7.3\ifmmode\pm\else\textpm\fi{}0.5$ Debye. The internuclear distance, derived from the moment of inertia, is 2.60\ifmmode\pm\else\textpm\fi{}0.16 angstroms.

It has recently been found that when a molecular gas is excited by electronic bombardment the subsequently emitted light is polarized. In this paper the authors investigate the possibility of studying molecular states excited by this technique in the presence of magnetic and/or electric fields. The measurements are made on the polarization of the light emitted from a level for which the total angular momentum is known. They extend to diatomic molecules the theory of irreducible tensor operators, previously applied to such experiments in atoms. All resonant effects observed in atoms may be expected in molecules, for instance in the presence of the magnetic field the effects of level crossing and magnetic resonance, including their transmission in a cascade decay. When an electric field is added, new effects may arise in polar molecules and make it possible to measure the permanent electric dipole moment and the Lambda doubling in some cases.

An electric field of uniform intensity can only induce movement of net electric charge. Fields having non-uniform spatial distribution, on the other hand, will also interact with oriented symmetric distributions of opposing charges, such as dipole layers. The present paper is concerned with the possibility of determining potential differences between two phases with the aid of a non-uniform electric field. A general solution is first given for the force exerted on a charge distribution containing free charge, as well as a dipole layer, in a non-uniform electric field. Application to the determination of the contribution of adsorbed ions to the Volta potential ψ0 is then indicated, and a numerical solution for a sphere of any given conductance is given in the appendix.

Of the methods which have been devised for the measurement of angles between covalencies, the one based on measurements of electric dipole moments is among the most valuable. Descriptions of considerable experimental work on the subject have been published by several authors, but the discussions of the basis of the method, its further possible applications, the possible errors and their probable importance, are not only scattered, but incomplete. It therefore appeared desirable that a more complete, general treatment of these matters should be given, and the present communication is an attempt to do this.

The present paper considers the VLF radiation characteristics from a thin dipole antenna in a warm magnetoplasma. Formal solutions are derived for the portions of the dipole radiation resistance due to the thermal modes (Rt) and the whistler mode (Rw). In this derivation the ions are assumed to be cold, and the effects of finite electron temperatures are included by means of a scalar pressure term. Two particular orientations of the dipole are considered (parallel and perpendicular to the static magnetic field line). A detailed analysis is made for frequencies in the range between the electron gyrofrequency (fHe) and the lower-hybrid-resonance frequency (fLHR). Several numerical plots of Rt ∥, and Rw∥, are presented for typical VLF magnetospheric plasma parameters. They show that for frequencies ( f) not close to fLHR, Rt∥, is generally < 2 x 10-1 Rw∥, whereas as f → fLHR, R t , ≃ 10-1 Rw and R t∥ ≃ Rw∥. Using these numerical values of Rt∥, and Rw∥,, the dipole whistler mode radiation efficiences ηw have been estimated for a number of specific cases. In most cases ηw ≳ 70 %, but falls as low as ∼ 38 % at f ≃ f≳ LHR.

In this paper we propose that chemicals such as acetylcholine are electric dipoles which when oriented and arranged in a large array could produce an electric field strong enough to drive positive ions over the junction barrier of the post-synaptic membrane and thus initiate excitation or produce depolarization. This theory is able to explain a great number of facts such as cleft size, synaptic delay, nonregeneration, subthreshold integration, facilitation with repetition, and the calcium and magnesium effects. It also shows why and how acetylcholine could act as excitatory or inhibitory transmitters under different circumstances. Our conclusion is that the nature of synaptic transmission is essentially electrical, be it mediated by electrical or chemical transmitters.

A new theory of the solvent effects is presented in this paper, in which the solute molecule is assumed to have a spheroidal form and have an electric dipole moment directed in the axis of rotation at its centre. The cavity field and the reaction field, etc. are calculated as the functions of the shape of the solute molecule and the dielectric constant of the solvent, and the molecular polarization is also calculated. Theoretical curve, expressing the molecular polarization v s . the dielectric constant of the solvent, obtained from this theory shows a fairly good agreement with the experimental results. The curve shows that the molecular polarization has a maximum value for a small dielectric constant of the solvent and its value decreases for larger dielectric constants.

The power radiated by oscillating magnetic and oscillating electric point dipoles is calculated for the case where the dipoles are immersed in a cold, streaming plasma. The power output of the dipoles in a streaming plasma is less than it is in a stationary plasma, although the correction term is of order β2, where β is the ratio of the plasma's streaming velocity to the velocity of light. The power output is calculated by a generalized Poynting vector method, using electromagnetic‐field expressions derived from a set of linearized, covariant cold‐plasma equations. The results of this paper are compared with the results of Daly, Lee, and Papas, and of McKenzie, who calculate the power output of the oscillating electric dipole from a ``dispersive medium'' point of view.

Numerous types of resonance methods for the measurement of dielectric constants have been described by different investigators. That detailed in the present communication has no claim to originality, but it is a simple, whilst at the same time reliable, form, which has proved to be very useful for the measurement of the dielectric constants of dilute solutions for the purpose of dipole moment determination. A fairly powerful oscillator is used, enabling the valveless resonance circuit to be some distance removed from it, whilst still receiving ample “pick-up” for the measurements. Resonance in the pick-up circuit is detected by means of a low-resistance thermo-junction, introduced directly into the circuit. The resistance thus introduced does not damp the oscillation unduly. The very small conductivity of the solvent liquids employed does not produce any appreciable error owing to the current resonance not occurring at the same tuning capacity as the voltage resonance.

The influence of vibration‐rotation interaction on line intensities in vibration‐rotation bands of diatomic molecules had been recognized and treated approximately many years ago. In the present paper matrix elements have been calculated for the P and R branches of the 0—1, 0—2 and 1—2 transitions taking into account the interaction of rotation and vibration as well as the mechanical and electrical anharmonicity. For the 0—1 and 1—2 transitions the intensities of corresponding absorption lines in the P and R branches are proportional, in first order approximation, to [1+4γθJ]J and [1—4γθ(J+1)](J+1), respectively, where J is the rotational quantum number of the initial state, γ=2Be/ωe, θ=M0/M1re and M0 and M1 are the first two coefficients in the electric dipole moment expansion about the equilibrium internuclear distance re. Corrections to the above expressions that are proportional to γ2 have also been obtained. Formulas are given for the total integrated band intensity and for the line intensities summed over each branch taken individually. In the case of certain molecules, such as HCl for which θ≅1, it is possible to determine the magnitude of sign of θ by applying the above analyses to experimental data. For molecules such as CO, where θ≪1, the effect is negligible for the fundamental transition. A semiclassical interpretation of the influence of vibration‐rotation interaction on line intensity has also been given.

The infra-red absorption of ionic crystals differs in important details from the predictions of the theory based on first approximations. It is known that this discrepancy may be due to two effects which are neglected in such a theory, namely, to the anharmonic terms in the potential energy and to those terms in the dipole moment which are of higher order than the first in the displacement co-ordinates. These higher-order terms in the dipole moment arise from the deformation of the electron shells. The present paper develops in a systematic way the influence of these higher-order effects on the static dielectric constant. Because of the dispersion relations, the terms occurring in the static dielectric constant must also appear in the infra-red absorption spectrum . It is found that the third- and the fourth-order potential, the second- and the third-order dipole moment, and cross-terms between the second-order moment and the third-order potential, all con­tribute terms in the same order to the static dielectric constant. It is also found that the third-order potential contains important contributions from the long-range dipolar inter­action. These dipolar contributions are proportional to the product of the first- and second-order dipole moments, and it follows that in ionic crystals a large second-order moment automatically results in a large third-order potential. It is suggested that these dipolar contributions to the third-order potential may be responsible for the fact that in the infra-red spectra of different ionic crystals not only the intensity of the side band but also the width of the main band varies in the same way as the deformability of the electron shells.

The purpose of this paper is to give the complete classical theory of a spinning particle moving in a Maxwell field. The particle is assumed to be a point, and its interaction with the field is described by a point charge g 1 and a point dipole g 2 . The Maxwell equations are assumed to hold right up to the point representing the particle. Exact equations are then derived for the motion of the particle in a given external field which are strictly consistent with the conservation of energy, momentum and angular momentum, and hence contain the effects of radiation reaction on the motion of the particle. It is shown that in the presence of a point dipole the energy tensor of the field can and must be redefined so as to make the total energy finite. The mass, the angular momentum of the spin, and the moment of inertia perpendicular to the spin axis appear in the equations as arbitrary mechanical constants. Reasons are given for believing that for an elementary particle the last constant is zero, in agreement with relativistic quantum theory. In the general theory there is no relation between the electric and magnetic dipole moments of the particle and the state of its translational motion. A procedure is given for deriving from the general equations specialized equations consistent with the condition that the dipole is always a purely magnetic or electric one in the system in which the particle is instantaneously at rest. The radiation reaction terms are very much simpler in the former of these specialized cases than in the general case. The effect of radiation reaction is to make the scattering of light by a rotating dipole decrease inversely as the square of the frequency for high frequencies, just as for scattering by a point charge.

The idea that a molecule need not necessarily have a single Kossel Lewis-Langmuir electronic structure, but may be a hybrid of several such, is not new in chemistry, Recently, however, it has been given a much more definite meaning, and has been made amenable to quantititative treatment by the application of wave mechanics to the problem; moreover, it is now realised how extensive the phenomenon is, owing largely to the work of Pauling and his collaborators on energies and internuclear distances. It is the purpose of this paper to show that it is possible, from electric dipole moment data, to decide independently whether or not there is resonance in a molecule, and also to obtain a rough idea of the nature of the more important parent structures and of their relative importance.

In this paper we propose that the physical behavior of the electric dipoles at the membraneinterface is mainly responsible for the observed phenomena in nerve excitation and conduction. The underlying molecular mechanisms are conceived to be dipole reorientation, relaxation and flip-flops. It is suggested that quantum transitions of electric dipoles and a few first principles provide a real physical basis for the neural behavior as manifested macroscopically. This dipole theory gains a strong support from the most recent discoveries of negative fixed surface charge on axon membranes, infrared emission from stimulated nerve and the birefringence change which coincided with the action potential in squid axon. It can also offer an explanation for the heat production and absorption in excited nerves. A brief discussion will be given to the memory mechanism in terms of the field-dipole interaction during the RNA synthesis in nerve cells.

This paper deals theoretically with some aspects of the influence of a non-homogeneous electric field on the laminar convective motion and heat transfer in paraelectric gas. i.e. a gas consisting of molecules having a permanent electric dipole moment. It is found that, due to the variation of the dielectric susceptibility with temperature, the electric field produces an electrical buoyancy force. Convective velocities and heat transfer in the gas near a heated surface are found to be increased or decreased according as the electrical buoyancy force acts with or in opposition to the net force of the existing pressure gradient and gravitational buoyancy force. The equations of motion for a paraelectric gas in the presence of an electric field are derived in a simplified form by the use of approximations similar to those of Boussinesq (1903). An exact solution of these equations is presented for the problem of laminar convection flow, under a pressure gradient, between vertical concentric cylinders which are maintained at different electrostatic potentials and whose wall temperatures decrease uniformly with increasing height. Here the electric field induces a heated down-flow to be superimposed on the existing cooled up-flow (or heated down-flow). Boundary-layer equations are also derived for the laminar convective motion due to a heated charged sphere. These equations are solved by an approximate method due to Squire (1938).