Effect of wavelength

Effect of wavelength on the linearity of a Beer s law calibration curve. 

Effects of wavelength of irradiating light and irradiation temperature 134... 

In order to calculate particle size distributions in the adsorption regime and also to determine the relative effects of wavelength on the extinction cross section and imaginary refractive index of the particles, a series of turbidity meas irements were made on the polystyrene standards using a variable wavelength UV detector. More detailed discussions are presented elsewhere (23) > shown here is a brief summary of some of the major results and conclusions. 

B. Tenge and D.E. Honigs, The effect of wavelength searches on NIR calibrations. Abstracts of Papers of the American Chemical Society, 193(APR), 112 (1987). 

Murray, J. W, Garman, E. and RavelU, R. (2004). X-ray absorption by macromolecular crystals the effects of wavelength and crystal composition on absorbed dose. /. Appl. Crystallogr. 37, 513-522. 

The effect of wavelength upon the relative proportion of the products is very marked. When the 2537 A. line from a low-pressure mercury arc is used, the yield of all three ethanes is drastically reduced, while the yield of both halogenated methanes is enhanced. The 1,3-dichlorohexafluoropropane can no longer be detected. This effect is unlikely to be due to alternative primary processes, such as mercury photosensitization, since it is also observed under flash photolysis conditions. As before, it is considered that the additional energy given to the radicals at shorter wavelengths, increases the rate of abstraction and decreases the rate of combination because of the third-body restriction. Some evidence for this... 

Fluorescent and triplet state yields for benzene add to between 0.9 and 1.0 for exciting wavelengths greater than 2530 A. There is, however, some effect of wavelength and as the pressure is lowered it appears that vibrational relaxation is more rapid for some modes of vibration than for others. These data are based on the progression for which in the excited state there is one unit of the frequency 521 cm"1 (an asymmetric mode of vibration) and 0, 1, 2, etc., units of the frequency 923 cm-1 (symmetrical stretching). 

Figure 3. The effect of wavelength on the germination of lettuce seeds which were initially irradiated to establish 50% germination. Additional red light (600-700 nm) further promotes germination most efficiently, whereas far-red light (700-750 nm) inhibits germination. (Action spectrum after Flint and Alister [15].)...

The effects of wavelength of the light in the polarized beam on the magnitude and sign of the observed optical rotation are considered in Section 19-9. 

Tenge, B. and Honigs, D.E., The Effect of Wavelength Searches on NIR Calibrations Abstracts of Papers of the American Chemical Society 1987, 193(April), 112. 

The effect of wavelength of the UV light (germicidal white and fluorescent black lamps) on TCE conversion in the CFB photoreactor is shown in Fig. 6. As can be seen, the germicidal white lamp (254 nm) exhibits higher TCE conversion than the fluorescent black lamp (365 nm). It has been reported that variation of photon energy in excess of band gap of TiC>2 does not affect the product mixture from a photocatalyst reactor [12]. The increase of TCE conversion is caused by higher photon flux, rather than by increases... 

Fig. 6. Effect of wavelength of UV light on TCE conversion with a variation of Ug.

Scheme 7. Effect of wavelength on the carbonylation of n-decane and toluene by the RhCI(CO) (PR3)2 system.

There is no reliable information available on the quantum yield, the product analysis, or the effect of wavelength. It is conceivable that the mechanism of the primary process depends strongly on the wavelength used. 

To large extent, the scientific literature is at least partially silent with respect to the effect of wavelength on photocatalysis. At most, there is some consideration to the fact that the absorption coefficient for 365 nm photons is significantly smaller than that for 254 nm photons, hence a thicker layer of photocatalyst is required with the former. Another effect of the shorter wavelength is the potential formation of active species that might play a role in the photooxidation reaction. 

The effect of wavelength on the (piantum yield of CO production from the photolysis of CII2CO can be satisfactorily interpreted on the basis of the RE.K model, but unfortunately the lack of data on the precise bond dissociation energy prevents a uiiiciuc assignment of parameters. The wavelength dependence of the fluorescence of photoexcited /3-naphthyl-amine has also been reasonably well interpreted in terms of the rate of spontaneous isomerization to a inetastable state incapable of fluorescence. A model for k E) equivalent to the RRK model was used. 

A prominent effect of wavelength on the photodepolymerization of oligo-p-CPA nPr in solution has been observed. An appreciable amount of monomer is produced when the oligomer solution is irradiated with monochromatic light of 224 nm whereas the oligomer is stable when irradiated at 304 nm34. ... 

Figure 4 Effect of wavelength on the photodegradation of (0), nifedipine ( ), nitroso-derivative (A) nitro-derivative.

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