Crystal Violet, visible spectra

Unlike Michler s Hydrol Blue (6.153) and crystal violet (6.167 R = CH3), malachite green (6.168 R = CH3) shows two absorption bands in the visible region of the electromagnetic spectrum (Figure 6.1). In 98% acetic acid the long-wavelength absorption band (x-band) of... 

In the presence of the dye the photocurrent at both semiconductors is observed in the visible region of the spectrum, i.e., in that region where crystal violet absorbs light. Thus, sensitization is observed. Photoprocesses that take place at zinc oxide and gallium phosphide can be represented by schemes of Figs. 23c and 23b, respectively. 

As described above the procedures according to Frens is a suitable technique to produce colloid solutions. However the aimed red color is obtained after color changes from yellow to black, dark blue, violet, and finally shifts suddenly to red. These earlier stages of colloid synthesis absorb light substantially above 600 nm and can be isolated by a rapid cool-down or addition of metal ions blocking crystallization of the gold colloid. With such glass-type non-crystalline colloids also resonance enhancement at A, > 600 nm is achieved, which enables to shift the desired absorption peak all over the visible spectrum to IR. 

From the color (absorption spectrum) of a complex ion, it is sometimes possible to deduce the value of Aq, the crystal field splitting energy. The situation is particularly simple in 22Ti, which contains only one 3d electron. Consider, for example, the Ti(H20)5 + ion, which has an intense purple color. This ion absorbs at 510 nm, in the green region. The purple (red-violet) color of a solution of Ti(H20)6 + is what is left over when the green component is subtracted from the visible spectrum. Using the equation... 

The dark red-violet crystals of syw-c/x-[Co(edda)(en)] NO3 dissolve in water at room temperature to give a solution stable to isomerization. The visible absorption spectrum in water shows 9 (87.3), 448 (shoulder),... 

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