Electric field oscillations

Fig. 4.49. Motion of positive ions in a uniform magnetic field B. (a) The radius is a function of ion velocity, but the frequencyof circulation is not. (b) Excitation of the ions by an RF electric field oscillating at their cyclotron resonance frequency. Adapted from Ref. [196] by permission. John Wiley Sons, 1986.

Figure 20-22a shows essentials of one common surface plasmon resonance measurement Monochromatic light whose electric field oscillates in the plane of the page is directed into a prism whose bottom face is coated with a thin layer (—50 nm) of gold. The bottom surface of the gold is coated with a chemical layer (—2-20 nm) that selectively binds an analyte of inter-... 

Brewster window A flat optical window tilted at an angle such that light whose electric vector is polarized parallel to the plane of the window is 100% transmitted. Light polarized perpendicular to the window is partially reflected. It is used on the ends of a laser to produce light whose electric field oscillates perpendicularly to the long axis of the laser. 

A dipole exists when the centers of positive and negative charge do not coincide. When exposed to an electric field, these oppositely charged centers will move in opposite directions either toward each other or away from each other. In infrared radiation, the direction of the electric field oscillates, causing the positive and negative centers within polar bonds to move toward each other and then away from each other. Thus, when exposed to infrared radiation, the polar bonds within a compound stretch and contract in a vibrating motion. 

As is shown in Figure 9.3, a wire grid polarizer will attenuate light polarized parallel to the conducting wires. This is a result of attenuation of the electric field oscillating... 

Bawin, S. M. Adey, W. R. Sensitivity of calcium binding in cerebral tissue to weak environmental electric fields oscillating at low frequency. Proc. Nat. Acad. Sci. USA 1976, 73, 1999-2003. 

The dipole moment of order 3, induced in a molecule by three electric fields oscillating at frequencies cug, cug, [Pg.198]

The vast majority of crystals are anisotropic, that is, their properties are not the same in all directions within the crystal. Light is said to be plane polarized (also called linearly polarized) when the electric field oscillates in a straight line. When, on the other hand, the electric field vector travels aronnd a circle, then the light is said to have circnlar polarization, and when the ends of the vector travel in an ellipse, it is said to be elliptically polarized. 

Since the dipoles are unable to follow the higher frequency electric field oscillations, the permittivity falls at the higher frequency and the substance behaves increasingly like a non-polar material. 

Figure 24-1 Wave nature of a beam of single-frequency electromagnetic radiation. In (a), a plane-polarized wave is shown propagating along the y-axis. The electric field oscillates in a plane perpendicular to the magnetic field. If the radiation were unpolarized, a component of the electric field would be seen in all planes. In (b), only the electric field oscillations are shown. The amplitude of the wave is the length of the electric field vector at the wave maximum, while the wavelength is the distance between successive maxima.

The incident light produces oscillating electric and magnetic fields in the transverse direction (in the xy plane) at every point along the beam. In a typical case of a vertically polarized laser light, the electric field oscillates... 

Fig. 3 Amplitudes of normal-to-plane interwell electric field oscillations at the center plane between the two layers of 2D electron strips in the anticrossing regime (rf=19.8 nm, solid curve) and far from the anticrossing regime (rf=27 nm, dashed curve). The amplitude of the interwell electric field is normalized to the amplitude of the electric field of the incident terahertz wave.

By Earnshaw s theorem, it is impossible to make a trap for ions static electric fields, but Penning in 1936 developed a stable ion trap that was a combination of a static uniform magnetic field and inhomogeneous electrostatic fields. In 1958 Paul and his associates made a successful electric quadrupole ion trap without a magnetic field by having the electric field oscillate sinusoidally at radio frequencies. 

Thus, for a frequency of 2.45 GHz these molecules can follow electric field oscillations, unlike substances which are strongly associated, for example water and alcohols, and therefore have dielectric loss at 2.45 GHz. Consequently the solvents which have dielectric loss are water, MeOH, EtOH, DMF, DMSO, and CH2CI2. Dielectric loss is negligible for nonpolar solvents such as CeHe, CCI4, and ethers, although addition of small amounts of alcohols can strongly increase the dielectric loss and microwave coupling of these solvents. 

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