Pigment chemistry

Resonance Raman Spectroscopy. If the excitation wavelength is chosen to correspond to an absorption maximum of the species being studied, a 10 —10 enhancement of the Raman scatter of the chromophore is observed. This effect is called resonance enhancement or resonance Raman (RR) spectroscopy. There are several mechanisms to explain this phenomenon, the most common of which is Franck-Condon enhancement. In this case, a band intensity is enhanced if some component of the vibrational motion is along one of the directions in which the molecule expands in the electronic excited state. The intensity is roughly proportional to the distortion of the molecule along this axis. RR spectroscopy has been an important biochemical tool, and it may have industrial uses in some areas of pigment chemistry. Two biological appHcations include the deterrnination of helix transitions of deoxyribonucleic acid (DNA) (18), and the elucidation of several peptide stmctures (19). A review of topics in this area has been pubHshed (20). 

T. C. Patten, ed.. Pigment Handbook, 2nd ed., 3 vols., Wdey-Interscience, New York, 1979. Written by a number of speciaUsts in the pigment field the three volumes describe pigment chemistry and appHcations. 

Naphthalene derivatives as coupling components generally couple better than their benzene analogs the latter only play a minor role in pigment chemistry. 

Linear oligopyrroles and bile pigments, chemistry of 89MI19. 

Should a researcher not interested in pigment chemistry be interested in silica coatings on titania It is interesting to digress at this point and... 

This paper explains how to use statistical tools to evaluate the reproducibility of color testing. Several pigment chemistries combined with several test methods were evaluated in hopes of establishing a test that both the statistician and color technician would endorse. 

Cadmium metal is silvery white and reasonably soft. Although it does form some complexes, its pigment chemistry is entirely concerned with the +2 state. 

It exhibits several valency states, -2 (selenide), -4 (selenite) and -6 (selenate). Pigment chemistry is concerned solely with the -2 state. 

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