Electric field static, atoms

In the presence of a static, spatially uniform electric field Ea, the electronic cloud of atomic and molecular systems gets polarized. The energy, W, can be written as a Taylor series [1-3]... 

The static dipole polarizability is the linear response of an atomic or molecular system to the application of a weak static electric field [1], It relates to a great variety of physical properties and phenomena [2-5]. Because of its importance, there have been numerous ab initio calculations of isolated atomic and molecular polarizabilities [6-14]. Particular theoretical attention has been dedicated to the polarizability of free atomic anions [15-21] because of its fragility and difficulty in obtaining direct experimental results. In recent years theoretical studies have... 

A. Scrinzi, Ionization of multielectron atoms by strong static electric fields, Phys. Rev. A 61 (4) (2000) 041402. 

Continuum solvation models consider the solvent as a homogeneous, isotropic, linear dielectric medium [104], The solute is considered to occupy a cavity in this medium. The ability of a bulk dielectric medium to be polarized and hence to exert an electric field back on the solute (this field is called the reaction field) is determined by the dielectric constant. The dielectric constant depends on the frequency of the applied field, and for equilibrium solvation we use the static dielectric constant that corresponds to a slowly changing field. In order to obtain accurate results, the solute charge distribution should be optimized in the presence of the field (the reaction field) exerted back on the solute by the dielectric medium. This is usually done by a quantum mechanical molecular orbital calculation called a self-consistent reaction field (SCRF) calculation, which is iterative since the reaction field depends on the distortion of the solute wave function and vice versa. While the assumption of linear homogeneous response is adequate for the solvent molecules at distant positions, it is a poor representation for the solute-solvent interaction in the first solvation shell. In this case, the solute sees the atomic-scale charge distribution of the solvent molecules and polarizes nonlinearly and system specifically on an atomic scale (see Figure 3.9). More generally, one could say that the breakdown of the linear response approximation is connected with the fact that the liquid medium is structured [105],... 

The electron source of the PIMMS is an argon plasma. Inside the plasma chamber the gas is ionized by a 2.45 GHz microwave field, ignited by an electric spark. In the plasma chamber free electrons are created, that are accelerated by a static electric field for impact ionization of the sample gas atoms. The layout of the plasma chamber has to incorporate both the fluidic and the electrostatic requirements. On the one hand the gas apertures of the chamber must have the appropriate dimensions to assure that the gas flow out of the chamber is low. On the other hand the geometry must be such that most of the electrons are generated close to the outlet of the chamber and can be extracted through this small aperture. Electrons should be generated close to the acceleration field, which intrudes the chamber only to a small depth. 

An important aspect in the study of the dipole polarizability of a reference molecule in solution is related to the separability problem, i.e., the distinction between the reference and the environment. Of course, the application of an external static homogeneous electrical field affects both the reference and the solvent molecules (in the present case, atoms). The use of response function, thus avoiding the external field, minimizes this problem, but still has the conceptual problem of distinguishing the solute and the solvent. It is normally assumed that a simple separability is a reasonable first approximation, particularly for weakly interacting systems. The interaction polarizability of weakly interactive systems... 

Similarly as the trace, the anisotropy of the polarizability tensor of diatomic colli-sional systems can also be related to some macroscopic properties, namely to the refractive properties of atomic gases. The so-called Kerr constant, the anisotropy of the refractive index in the parallel and perpendicular directions to the external static electric field is given by,... 

An important extension of the measurements was the application of a static electric field, applied between the Stark plates, and the consequent observation of Stark components in the double resonance lines, from which the electric dipole moment could be determined. An example of the spectra obtained is shown in figure 11.7(b). In their later work Field and Bergeman [12] replaced the manganese atomic emission line with white light from a CS molecular discharge lamp and they were then able to study the A-doublet transitions in rotational levels J — 1 to 9 of the A 1 n state. Their... 

In the presence of a uniform static electric field (F) the energy of an atom may be expressed by the Taylor series[ 14]... 

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