Beam electromagnetic radiation

Non-polarized electromagnetic radiation, of course, comprises two perpendicular polarizations, which can change both in amplipide and in phase with respect to each other. If the two polarizations are in phase with each other, the resultant is just another linearly polarized beam, with the resultant polarization direction given by a simple vector addition of the... 

In absorption spectroscopy a beam of electromagnetic radiation passes through a sample. Much of the radiation is transmitted without a loss in intensity. At selected frequencies, however, the radiation s intensity is attenuated. This process of attenuation is called absorption. Two general requirements must be met if an analyte is to absorb electromagnetic radiation. The first requirement is that there must be a mechanism by which the radiation s electric field or magnetic field interacts with the analyte. For ultraviolet and visible radiation, this interaction involves the electronic energy of valence electrons. A chemical bond s vibrational energy is altered by the absorbance of infrared radiation. A more detailed treatment of this interaction, and its importance in deter-... 

The vibrational motions of the chemically bound constituents of matter have fre-quencies in the infrared regime. The oscillations induced by certain vibrational modes provide a means for matter to couple with an impinging beam of infrared electromagnetic radiation and to exchange energy with it when the frequencies are in resonance. In the infrared experiment, the intensity of a beam of infrared radiation is measured before (Iq) and after (7) it interacts with the sample as a function of light frequency, w[. A plot of I/Iq versus frequency is the infrared spectrum. The identities, surrounding environments, and concentrations of the chemical bonds that are present can be determined. 

Beams of electromagnetic radiation of appropriate wavelength ate scattered when they interact with the gradients inherent in stractuied materials. By measuring the ways in which the intensity of scattered radiation varies as a function of the angle at which the radiation initially strikes the sample, the wavelength of the radiation, and the time, many aspects of the stmcture of materials can be inferred. 

I is defined as the energy / unit area of a beam of electromagnetic radiation. 

To explain the photoelectric effect, Einstein (1905) postulated that light, or electromagnetic radiation, consists of a beam of particles, each of which travels at the same velocity c (the speed of light), where c has the value... 

One of the first proposed processes for obtaining electromagnetic radiation up to the X/y-ray range using laser beams was the Thomson scattering (see e.g., [88] and references therein). As it is known, this is the scattering of... 

In addition to emitting electrons, a solid bombarded with ions in the keV range emits electromagnetic radiation from the near infrared to the near ultraviolet, with a photon yield of typically KT4 per incident ion for a metal, and 10 2 to 10 l for insulators. If the primary beam is intense, as in the dynamic SIMS range, and the sample is an insulator, one observes a bright glow at the point where the beam hits the sample. With conductors, the effect is not or hardly observable. 

Alternative sources of primary X-rays now include synchrotron radiation (Pollard et al., 2007 290). The synchrotron is a large electron accelerator which produces electromagnetic radiation across the entire spectrum, with high spectral purity and very high beam intensity. At specific stations around the storage ring, particular sections of the electromagnetic spectrum are selected... 

A double beam instrument splits the electromagnetic radiation into two separate beams, one for the reagent blank, and the other for the sample. There are two ways to do this. The first method uses a mirror that is half silvered and half transparent. As shown in Fig. 5.17 this results in a continuous beam of light for both the sample and reagent blank. 

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