Structures magnetic/electric field influences

The use of an electric field is not the only effective way to influence the LC polymer structure, magnetic fields displays a closely similar effect167 168). It is interesting as a method allowing to orient LC polymers, as well as from the viewpoint of determining some parameters, such as the order parameter, values of magnetic susceptibility, rotational viscosity and others. Some relationships established for LC polymer 1 (Table 15), its blends with low-molecular liquid crystals and partially deuterated polyacrylate (polymer 4, Table 15) specially synthesized for NMR studies can be summarized as follows ... 

More recently, the Faraday eflfect (particulariy its dispersion and absorption) has been found to provide new ways of studying the structure of molecules and, even more so, of macromolecules and biopolymers. This is because the Faraday eflfect is primarily due to the direct influence of the electric field on the optical polarizability of the microsystems (it thus differs essentially from natural optical activity). The theoretical and experimental results obtained in these studies are presented in the articles of Buckingham and Stephen, and Schatz and McCaflfery. Existing laser and high-magnetic-fidd techniques permit studies of non-linear variations in the Faraday eflfect, particularly with regard to macromolecular and colloidal substances. ... 

The Stark effect on the magnetic fine structure occurs as a result of disturbance of atomic levels under the influence of the relativistic and correlation effects as well as the interaction with external electric field F. If the fields are weak enough the centre of multiplet is shifted and there occurs the splitting of sublevels of atomic multiplet n, L, J. The dipole moment induced in an atom by a uniform electric field F is for most purposes expressed as a linear function of F, but higher... 

We have developed an unified adiabatic approach allowing one to tackle transport problems in traps of different geometry. The magnetic and electrical fields, charge screening, and other factors (a spin-orbit interaction, hyperfine structure, etc) can influence the quantum dot paths within an easily tractable Breit-Wigner-resonance approximation for the electron scattering. The utility... 

Garbarczyk, J., Kamyszek, G. (2000). Influence of Magnetic and Electric Field on the Structure of IPP in Blends with Liquid Crystalline Polymers. In Abstracts of the 38-th Macromolecular lUPAK Symposium. Warsaw, 3, 1195. 

However, it is popular to use the director as far as possible to visualize liquid crystal structures. The director field shows elastic behavior, and can be influenced by external electric and magnetic fields. At interfaces, the orientation of n is usually anchored due to interactions between the liquid crystal... 

In this section we treat some physical properties of the NaCl-type compounds that reflect the influence of the crystal electric field on the energy of the J ground state of the cationic 4f" levels. Due to the small radius of the 4f orbitals the crystal field of the anion neighbors acts as a small perturbation only. At room temperature no particular f orbitals are favored so that the crystal structure, for instance, is determined by the cation size only. Below say 100 K the influence of the crystal field on the physical properties becomes evident. In contrast to certain rare earth phosphates, arsenates and vanadates, however, crystal-structure distortions never occur due to the Jahn-Teller effect alone but are always coupled with a magnetic transition, that is, the structural changes are due to a magnetostrictive effect. However, the crystal field influences and may even inhibit magnetic transitions as in the case of certain Tm compounds. 

In the case of liquid lattices, the difficulty in adequately characterizing their structures renders them unsuitable for treatment by quantum mechanics. Accordingly, liquid lattices are often treated classically by considering the effects of molecular rotations and translations, with characteristic correlation times, r, on time-dependent magnetic and electric fields that may influence relaxation processes. Accordingly, it becomes convenient to depart from the phonon description of sound and adopt a classical view of this as the sinusoidal propagation of a pressure wave through a medium. 

Almost all liquid crystals are diamagnetic. An exception is made with those substances whose molecules incorporate free radicals with permanent magnetic moments. Anisotropy of electric and optical properties of the liquid crystals, closely connected with anisotropy of their molecular structure, causes variety of their electrooptical properties. The external electric field can render a very strong influence on optical properties of liquid crystals, changing, for instance, their transparency and color. Therefore they have found very wide application as electronic indicator panel in microelectronics (calculators, watches and other devices). Such types of devices require very low voltage (parts of volts) and power (pW). 

The possibility to affect the structure of an LC polymer by the influence of electric and magnetic fields is demonstrated. The kinetics and the mechanism of structural rearrangements are discussed. 

Considerable interest centres on the Mantle constituting, as it does, more than half of the Earth by volume and by weight. Attention has been focussed on several problems, including the chemical composition, mineralogy, phase transitions and element partitioning in the Mantle, and the geophysical properties of seismicity, heat transfer by radiation, electrical conductivity and magnetism in the Earth. Many of these properties of the Earth s interior are influenced by the electronic structures of transition metal ions in Mantle minerals at elevated temperatures and pressures. Such effects are amenable to interpretation by crystal field theory based on optical spectral data for minerals measured at elevated temperatures and pressures. 

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