Compound photoelectric effect

Elastic-inelastic collision model, Szilard-Chalmers reaction and, 1 269 Electrical conduction, in organic superconductors, 29 278-286 Electrical conductivity of chalcogenide halide compounds, 23 331 of Group IB, 23 337-339, 342, 346-349 photoelectric effects, 23 368, 410 semiconductors, 23 368, 390, 395-396, 400-402, 410-412 superconductors, 23 375-377 of graphite intercalation compounds, 23 290, 294, 309-310, 312, 317-318 Electric discharges arc type, 6 146-147 chemical reactions in, 6 189-191 chemical reactions in, 6 143-206... 

For normal chemical systems, the characterization of mixtures of compounds is undesirable and generally unnecessary if means of separation of the components are available. However, photochromic systems inherently display properties of mixtures except when the system is completely converted to either of its forms. This causes measurements of heats of combustion, photoelectric effects, and electrical conductivity to be particularly difficult. A variety of such studies is presented in the following sections to illustrate the utility of these measurements. 

Since photoelectric effects vary widely for different compounds one would predict some change should accompany photochromic activity which indeed generates new electronic systems. These effects should be unique for each photochrome and hence there should be no general relationship between photochromism and photoelectric activity. This was found to be the case by Rao and Watson (168). 

The purpose of this chapter is to provide an overview of a rather wide array of experimental techniques that can tell us about the electronic structure of molecules. Some of these techniques, such as photoelectron (PE) spectroscopy, which is based on Einstein s photoelectric effect, are generally applied to gas-phase molecules. They can give high-resolution spectra, providing information about molecular vibrations and even, in a few cases, rotations. At the other end of the scale, UV/vis spectroscopy, particularly as applied to transition-metal complexes in solution, involves broad bands, and although it is an important and widely-used method, the information it gives is limited. Emission spectroscopy of transition-metal compounds has also become important. 

Additional topics have been added to the text, which include a treatment of real gases in Chapter 5 and coverage of photoelectric effect to Chapter 7. In addition, the Sample Exercises in Chapter 2 have been revised to cover the naming of compounds given the formula and the opposite process of writing the formula from the name. 

The lead compounds PbS, PbSe, PbTe are narrow-gap semiconductors that have been widely investigated for infrared detectors, diode lasers, and thermo-photovoltaic energy converters. Their photoconductive effect has been utilized in photoelectric cells, e.g., PbS in photographic exposure meters. Integrated photonic devices have been fabricated by their heteroepitaxial growth on Si or III-V semiconductors. 

Multiplet Splitting. Interaction of a core vacancy resulting from the photoelectric process with unpaired electrons in a valence shell induces multiplet splitting in the lines corresponding to the emitted electron. Thus, the 3s level in the transition metals exhibit relatively simple splittings, often of several eV, specific for each chemical state (1 ). The 2p levels are split into multiple lines, and the effect of their convolution is to widen the apparent split of the doublet (14). Frost, et al (15) tabulate the 2p splitting for cobalt compounds, which varies in the range 14.6 to 16.1 eV. There should be similar variability... 

Kirschner and Ahmadhave applied the Pfeiffer effect to the resolution of complex inorganic compounds. These authors allowed a Pfeiffer effect to develop in the initially racemic nickel(II) tris(2,2 -dipyridyl) complex in levo-mahc acid, and then succeeded in freezing out the non-equimolar mixture of enantiomers from the system by means of precipitation of the enantiomers as the relatively insoluble perchlorates. These insoluble perchlorates were then redissolved by allowing an aqueous suspension of them to come in contact with Amberlite IRA-400 anion exchange resin in the chloride form, and the optical rotation of a solution of the soluble complexes (as chlorides) was then read on a photoelectric polarimeter. Table 2 shows the optical rotations of this complex, and Fig. 7 shows a comparison of the... 

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