Ultraviolet spectral range

The absorption of exciting photons, most often in the ultraviolet spectral range, by a semiconductor promotes electrons from the filled valence band (where electron vacancies, electron deficiencies, or holes are thus formally created) to the vacant conduction band (Fig. 1). The electron-hole pairs can recombine either directly (band-to-band recombination) or, most... 

Ganeev RA, Ryasnyansky AI, Stepanov AL, Usmanov T. Nonlinear optical response of silver and copper nanoparticles in the near-ultraviolet spectral range. Phys. Solid State 2004 46 351-... 

M. Otto, H. Bandemer, A fuzzy method for component identification and mixture evaluation in the ultraviolet spectral range. Anal. Chim. Acta 191 (1986) 193. 

The n electrons are the most weakly bound of all the electrons in the molecule they therefore have the lowest electronic excitation energies of the electronic system. These lie in the optical and near-ultraviolet spectral ranges. When aromatic molecules are ionised, it is from the tt-electron system that electrons are ejected. 

The electronic excited states of organic molecular crystals are clearly and in a readily understandable way derived from those of the free molecules (or of molecules in liquid solutions). This follows, as was already discussed in Chap. 2, from the fact that the intermolecular forces in crystals are relatively weak in comparison to the binding forces within the molecules. The excited states and the transitions between them are studied by means of optical spectroscopy, particularly in the visible and the ultraviolet spectral ranges. Here, we will explain the essential facts using... 

CT complexes often exhibit strong bands in the visible or ultraviolet spectral range. The absorptivity of the CT complex can be calculated from the absorptivity observed at the band maximum, if the molar linear absorption coefficient t and the path length L of the couvette are known ... 

In several regards laser absorption spectroscopy corresponds to microwave spectroscopy, where klystrons or carcinotrons instead of lasers represent tunable coherent radiation sources. Laser spectroscopy transfers many of the techniques and advantages of microwave spectroscopy to the infrared, visible, and ultraviolet spectral ranges. 

In the past several decades wide band gap II-VI semiconductors have attracted a significant research interest as promising candidates for high-performance optoelectronic devices such as light-emitting diodes (LEDs) and laser diodes operating in the blue or ultraviolet spectral range. To date ioific liquids have been employed as a solvent media for electrodeposition of CdTe, CdS, ZnTe, ZnS, CdSe, and ZnO II-Vl semiconductors. 

One research area that has benefited from extensive fluorescence investigations is the field of protein structure-function studies. There are three aromatic amino acids that absorb light in the ultraviolet spectral range, phenylalanine (Phe), tyrosine (lyr) and tryptophan (Trp). Because of their molar absorptivity the fluorescence of Tyr (2276 = 1405 m cm ) and Trp (e28o = 5579 cm" ) have... 

Component Identification and Mixture Evaluation in the Ultraviolet Spectral Range. 

Table 3 Component Identification in the Ultraviolet Spectral Range by Using a Fuzzy Criterion According to equation (24) and by Use of the Euclidean Distance Measure (from Ref. 5)...

WiEBERNEIT N. and Heitland P. (2001) Applications of ICP-OES with a new argon-filled CCD spectrometer using spectral lines in the vacuum ultraviolet spectral range, Appl. Spectrosc. 55 598-603. 

Q, Qy low-energy absorption bands of tetrapyrroles in the Vis/NIR spectral region RC reaction center (Type I and Type II relate to the homologies with PSI and PSII, respectively) UV ultraviolet spectral range (200 to 400 nm)... 

---