Cause of colors

Gas excitation, as cause of color, 7 326t, 328 Gas feeders, for swimming pools, 26 178 Gas-film coefficient, 15 695 Gas flammkohle coal grade (Germany), 6 713t... 

Interfacial polymerization processes, in microencapsulation, 16 445 446 Interfacial tension, 24 134 in polymer blends, 20 323, 333 of fats and oils, 10 822 Interference, as cause of color, 7 326t, 339-340... 

Rotational suspension separation encapsulation process, 16 450 Rotational viscometers, 21 731-737 computers in, 21 732 operation of, 21 736 Rotations, of molecules cause of color, 7 326t, 328 Rotavirus vaccine, 25 496 Rotaxanes, 17 61, 24 31, 33, 51 as molecular computers, 24 60 Rotenone (Chem-Fish Synergized,... 

Transition metal complexes, catalysts based on, 20 193 Transition-metal compounds cause of color, 7 326t, 328-331 Transition-metal coordination compounds, 7 582-584... 

Nassau, K. The Physics and Chemistry of Color The Fifteen Causes of Color, John Wiley Sons, Inc. New York, NY, 1982. 

Nassau has provided a tabulation of different causes of color related to various mechanisms found in science67. If his category transitions between molecular orbitals were expanded, it would include the mechanism found in vision. This is the transition between molecular orbitals of conjugated oxygen atoms. He also provided a set of energy band structures. However, these did not include the case of a pure organic semiconductor. Such a semiconductor does not exhibit a conduction band, only an excitation band. 

The structural and chemical causes of color in natural materials can be very complex. But basically, visible colors are caused and affected by the amount of a pigment or impurities present in a material, or the physical structure of its surface. Color is consistent for some materials, and not for others. This depends on the causes of the color. 

Nassau, K. (1983). The physics and chemistry of color. Fifteen causes of color. Wiley-Interscience, New York. [213, 215, 217, 229, 257]... 

C Whal is the cause of color Why do some objects appear blue to the eye while others appear red Is the color of a surface at room temperature related to the radiation it emits ... 

More detailed information on the physical causes of color can be obtained from books by Nassau (1983) and Bums (1993). 

Although ascorbic acid, particularly in the presence of iron or copper, is capable of increasing the rate of pigment loss, the rate of loss when none of these agents is present is already of a distressing magnitude. Thus some other cause of color loss has yet to be explained. 

We will treat color separately for the different minerals and just add a few notes here the importance of dopants is clear from Table 36.5. There are several different causes of color in gemstones. Most are associated with local trapped charges. 

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