Band mercury compounds

Table 4.1-178 Band structures of mercury compounds Mercury selemde (HgSe)...

Commonly used II-VI compounds include zinc sulfide, zinc selenide, zinc telluride, cadmium sulfide, cadmium telluride, and mercury cadmium telluride. These materials are not as widely used as the III-V compounds, one reason being that it is difficult to achieve p-type doping. Mercury cadmium telluride is used extensively in military night sights, which detect in the 8-13 im spectral band (a similar material, platinum silicide, is being developed for that purpose). The major applications ofCVD II-VI compounds are found in photovoltaic and electroluminescent displays. 

Fig. 5.6 (Left) Comparison of band energy levels for different II-VI compounds. Note the high-energy levels of ZnSe. Representation is made here for electrodes in contact with 1 M HQO4. The reference is a saturated mercury-mercurous sulfate electrode, denoted as esm (0 V/esm = +0.65 V vs. SHE). (Right) Anodic and cathodic decomposition reactions for ZnSe at their respective potentials (fidp, Fdn) and water redox levels in the electrolytic medium of pH 0. (Adapted from [121])...

The lignin model compounds and their derivatives used in this study were custom synthesized at Queen s University by Dr. R. Bowers (Colour Your Enzyme). CIDEP and conventional ESR experiments were conducted using either a Varian E-104 spectrometer or a customized Bruker X-band spectrometer, modified similarly as previously described (7). The light source used for in situ irradiation was either a super high pressure 200 W mercury lamp, a Lambda-Physik EMG101-MSC XeCl excimer laser at 308 nm., or a Quanta-Ray GCR-11 Nd YAG solid state laser equipped for all four harmonic generations. 

Figure 8.7. Changes in optical densities of vacuum-deposited thin solid films of compounds la (R = H), and la (R = Me), spiropyrans 19, 20, and a model compound 16 (photochemically inert) measured at the absorption maxima of the long-wavelength absorption band of the photocolored isomers as a function of time of irradiation (high-pressure mercury lamp DRSH-250, 365 nm). Relative colorabilities of the compounds, Arcl, were calculated to be equal to 19 (6-N02BIPS) = 1 1 (R = H) = 0.9 1 (R = Me) = 3.2 20 = 2.1.

Wavelength repeatability is a measure of the precision of wavelength measured. The bandwidth refers to the width of an emission band (from the monochromator) at half peak height. This value, normally provided by the manufacturer is accepted. Using a mercury vapor lamp one can also check the spectral width. A number of well defined emission lines at 243.7, 364.9, 404.5, 435.8, 546.1, 576.9, and 579 nm can be used to check spectral bandwidth. However, the accuracy of the absorbance measured is dependent on the ratio of spectral bandwidth to the normal bandwidth (NEW) of the absorbing species. Most active pharmaceutical compounds have a normal bandwidth of approximately... 

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