Far-IR radiation

The problem is praticularly serious for the very weak metal-adsorbate bonds which are expected in the far-infrared region. Recently the IR radiation from a synchrotron has been used as a source for in-situ measurements at the electrode-solution interface [19]. The far-IR radiation from a synchrotron has an intensity between 100 and 1000 times higher than standard black body sources. 

Modern bolometers are micro-machined from silicon. This type of bolometer is only a few micrometers in diameter and is usually placed in one arm of a Wheatstone bridge for measurements. The modem micro-bolometer has a fast response time and is particularly useful for detecting far-IR radiation (600-20 cm ). 

The samples were freestanding films with thickness 40-100 p,m. This thickness is greater than the electromagnetic penetration depth [5 = c/ 2tt xwo-(w), where c is the speed of light and 10 S/cm. Samples with or cTdc < 10 S/cm were first checked to determine whether they had transmitted far-IR radiation. Therefore, the reflectance can be analyzed using the Fresnel reflection coefficients for semi-infinite media [103]. 

Molecules composed only of light atoms absorb far-IR radiation if they have skeletal bending modes that involve more than two atoms other than hydrogen. Important examples are substituted benzene derivatives, which generally show several absorption bands. The spectra are frequently quite specific and useful fur identifying a particular compound. There are also characteristic group frequencies in the far-IR region. 

Combined far-IR radiation and vacuum drying has recently received more attention as the technique has proved effective in drying some types of fruits with the aim of producing fat-free fruit-based snacks. However, most studies are purely experimental, for example the drying of welsh onion by FIR radiation under vacuum conditions (Mongpreneet et al., 2002). Swasdisevi et al. (2009) considered a... 

Shimizu S, Self-extinguishing far-IR radiating heat insulative fibres containing substances having high amount of water of crystallization , JP 11,350,253,21 Dec... 

Techniques applicable to far-IR radiation in the terahertz (THz) frequency region have become accessible only recently. The respective developments are particularly important in the field of polymers, as collective vibrational modes of macromolecules on a picosecond timescale are excited by far-IR radiation of THz frequencies. This involves dry polymers as well as biopolymers contained in aqueous systems. Collective vibrations involve portions of the macromolecules, and can be best described as large molecular pieces beating against each other. Extensive molecular dynamics simulations, including various proteins and DNA, have identified twisting and vibrational modes in the range from 0.6 to 6.0 THz. Effectively, all... 

Whereas ESCA and other surface specific techniques are often the obvious method of choice, IR-ATR may be a suitable technique when the composite material is heavily filled, and the IR radiation does not penetrate to far into the sample material. An advantage of, e.g., IR is that the sample can be investigated under ambient conditions rather than under a high vacuum, as required with techniques such as ESCA. 

Radiation in the far IR from either cool dust associated with cirrus or warm dust associated with active star formation in luminous and ultra-luminous infrared galaxies. 

Infrared (IR) radiation refers broadly to that part of the electromagnetic spectrum between the visible and microwave regions. Of greatest practical use to the organic chemist is the limited portion between 4000 and 400 cm-1. There has been some interest in the near-IR (14,290-4000 cm-1) and the far-IR regions, 700-200 cm-1. 

Absorption of microwave radiation to excite molecular rotation is allowed only if the molecule has a permanent dipole moment. This restriction is less severe than it may sound, however, because centrifugal distortion can disturb the molecular symmetry enough to allow weak absorption, especially in transitions between the higher rotational states which may appear in the far IR (c. 100cm-1). Microwave spectroscopy can provide a wealth of other molecular data, mostly of interest to physical chemists rather than inorganic chemists. Because of the ways in which molecular rotation is affected by vibration, it is possible to obtain vibrational frequencies from pure rotational spectra, often more accurately than is possible by direct vibrational spectroscopy. 

Mixtures of fulleranes produced by hydrogenation of solid C60 films under atomic H flux have revealed spectral features that bear striking similarity to those observed in the diffuse interstellar medium, both in the far IR and in the UV spectral windows. Of course, one must be cautious not to overextend the interpretation of laboratory data, for a number of reasons firstly, because electron spectroscopy, the experimental technique used in these studies, differs in several important aspects from the spectroscopic methods employed in observational astronomy, and secondly, because of the specifics of specimen preparation and environmental conditions. In this regard, there is a need to explore the stability of fulleranes to energetic and corpuscular radiation (Cataldo et al. 2009). Nonetheless, our findings lend support to the suggestion of fulleranes as candidates for unidentified emission and absorption features of interstellar and circumstellar media. Whether or not they exist in sufficient abundance is still unclear however, their spectral features make them undoubtedly an ideal model system for laboratory studies of these fascinating astrophysical phenomena. 

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