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Faraday effect density

Apart from subtle exceptions, an isolated molecule differs from a molecule in a crystal in that the isolated molecule has no shape, whereas in a crystal it acquires shape, but loses its identity as an independent entity. This paradoxical situation is best understood through the famous Goldstone theorem, which for the present purpose is interpreted to state that any phase transition, or symmetry broken, is induced by a special interaction. When a molecule is introduced into an environment of other molecules of its own kind, a phase transition occurs as the molecule changes its ideal (gas) behaviour to suit the non-ideal conditions, created by the van der Waals interaction with its neighbours. An applied electric or magnetic field may induce another type of transformation due to polarization of the molecular charge density, which may cause alignment of the nuclei. When the field is switched off the inverse transformation happens and the structure disappears. The Faraday effect (6.2.3) is one example. [Pg.245]

Defined from 0 = V(y)B, where 0 is the angle of rotation of linearly polarized light through a medium of number density n, per unit length, for a longitudinal magnetic field strength R (Faraday effect)... [Pg.1662]

Chiral structure affects the spin density of photon in the wave zone, which is the helicity density. In other words, if atoms and molecnles are radiated, then the electrons are affected by torque leading to the imbalance between spin torque and zeta force established in the stationary state. The reaction affects the torque on photon, leading to circular dichroism, the Kerr effect, and the Faraday effect. Forbidden processes may of course be realized due to symmetry of ket vectors. [Pg.245]

Electrostatic Interaction. Similarly charged particles repel one another. The charges on a particle surface may be due to hydrolysis of surface groups or adsorption of ions from solution. The surface charge density can be converted to an effective surface potential, /, when the potential is <30 mV, using the foUowing equation, where -Np represents the Faraday constant and Ai the gas law constant. [Pg.544]

Here, kv is an electrochemical rate constant, and F is the faraday, the charge on 1 mol ofunivalentions. It contains the exponential term for the electrode potential (assuming a cathodic reaction in a region in which the rate of the back anodic reaction can be neglected). However, it does take into account the effect of diffusion on the observed current density, i. [Pg.533]

Maes, A., and A. Cremers. 1977. Charge density effects in ion exchange. Parti—Hetero valent exchange equilibria. J. Chem. Soc. Faraday Trans. I. 73 1807-1814. [Pg.163]

The effective area of the OTS-coated PtO electrode can be derived if the charge transfer resistance (K ) is known. Rct can be obtained from impedance data measured at a potential near the reversal potential (37, 33) Rct = RT/(nFAI0), where R is the universal gas constant, T is absolute temperature, n is the number of electrons transferred per molecule of TONE, F is Faraday s constant, I0 is the exchange current density, and A is the effective surface area. Because the impedance spectra of the PtO and PtO-OTS electrodes were measured under the same conditions, the value of Rct may be assumed to be affected only by the effective surface area. In Figure 3, the impedance data are replotted as 2 versus 1 /a)1 2, where a) is the angular frequency (2 tt/). Rct is estimated from the intercept on the Z axis by extrapolation. The Rct values are 95 and 980 fl for PtO and PtO-OTS, respectively. An OTS coverage factor, 0, can then be estimated from (1 — 0) = ct(Pto)/ ct(Pto-OTS> In is case 0 = 0.9. [Pg.491]

Dean et al [7] measured the Zeeman splitting of a luminescence line involving the 2p donor state, obtaining the electron effective mass m t=(0.24 0.01)mo and m /m, =0.36 0.01 for n-type cubic crystals. Measurements of infrared Faraday rotation due to free carriers were made by Ellis and Moss [8] at room temperature in a number of n-type hexagonal specimens belonging to the 6H and 15R polytypes of silicon carbide. One component of the total density-of-states effective mass was explicitly determined by this method. A value for the... [Pg.69]

Amorphous Ti02 films (starting material TiO) which were obtained by condensation on glass substrates of 30°C, crystallized under strong electron radiation (60 kV, current density = 15 A cm 2, measured with a Faraday cup) into rutile and anatase, as determined with selected area diffraction. Crystallization was found to be due to a temperature effect. [Pg.349]


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