Ultraviolet edge

This requires light with < 395 nm, at the ultraviolet edge of the visible region.) Finally, production of ozone occurs ... 

In reality, the inherent ultraviolet edge of a glass is rarely observed. Very small concentrations of iron and other impurities result in very intense absorption bands. Since the absorption of energy is due to the transfer of an electron from the cation to a neighboring anion, these absorptions are said to be due to a charge transfer transition and the absorption band is called a charge transfer band. These bands are so... 

The ultraviolet cutoff or the absorption edge for pure vitreous siUca is 8.1 eV or 153 nm (171). This uv cutoff is influenced by the impurity level and stoichiometry of the material. Several impurities, such as the transition metals (Fe, Cu, Ti, etc) and alkaU metal ions (Na, Li, K), degrade the ultraviolet performance, shifting the uv cutoff to longer wavelengths. Ferric ions (Fe " ) cause absorption or result in network defects under reducing conditions. This contaminant at only a few ppm can be detected as an absorption at 230 nm and below (176). 

Bohm, F, Edge, R, Lange, L, and Truscott, TG, 1998a. Enhanced protection of human cells against ultraviolet light by antioxidant combinations involving dietary carotenoids. J Photochem Photobiol B 44, 211-215. 

When the solvent has moved to the top of the plate (10-20 cm) or, preferably, to a line that has been scored across the plate about 1 cm from the top edge (Figure 3.4) the plate is removed and dried quickly. The separated bands can be visualized by using a suitable reagent or by viewing under ultraviolet light and their positions marked. 

G. Spitzer, Multiphonon Lattice Absorption D. L. Slierwall and R F. Potter, Emittance Studies H- R- Philipp and H. Ehrenveich, Ultraviolet Optical Properties M. Cardona, Optical Absorption above the Fundamental Edge . J. Johnson, Absorption near the Fundamental Edge... 

In the second place, the spectrum of 3 Lyr is a very peculiar one, characterized not only by photospheric absorption lines but also by emissions that are strong in H, and are also present in He, and by other features, which arise partly in the gaseous stream from the B8 II component and partly in the outer edges of the opaque disk that surrounds and hides the so far unobservable companion. As it has been shown by Batten and Sahade (1973), in the case of H a, and by Aylin et al. (1987), in the case of the resonance lines of C IV, Si IV and N V in the IUE ultraviolet range, the line profiles can be interpreted in terms of a superposition of two profiles, one of them a broad, relatively faint emission that shifts back and forth throughout the orbital cycle. The behavior of the radial velocities from this feature suggests that it shares roughly the expected orbital motion of the companion to the B8 II component and, therefore, that it may arise in the optically thick disk that surrounds it. 

Fig. 4.19, The tunnelling luminescence kinetics for the Ej-, Tb3+ pairs in Na20 3Si02-Tb3+ glass. The ultraviolet excitation was at 120 K with further short thermal excitation of electrons above the mobility edge (curve 1) and prolonged heating up to 70 K below the excitation...

---