Fraction of absorbed light

The study of quantum yields. The quantum yield is the fraction of absorbed light that goes to produce a particular result. There are several types. A primary quantum yield for a particular process is the fraction of molecules absorbing light that undergo that particular process. Thus, if 10% of all the molecules that are excited to the state cross over to the T state, the primary quantum yield for that process is 0.10. However, primary quantum yields are often difficult to measure. A product quantum yield (usually designated ) for a product P that is formed from a photoreaction of an initially excited molecule A can be expressed as... 

The absorption fraction of a particle is related to the volume of the particle. Thus, the larger the volume of a particle, the more of the incident light is absorbed. In contrast, reflectance is related to the particles surface area, being in turn dependent on material porosity. The absorption/remission function relates to the fraction of absorbed light, the fraction of remitted (or back scattered) light, and the fraction of light transmitted by a representative layer... 

Table 4.3 Fraction of absorbed light for some absorbance values...

The intensity of a spectral absorption band at a given wave length is expressed in terms of absorption or extinction coefficients, dehned on the basis of the Beer-Lambert law. The latter states that the fraction of incident light absorbed is proportional to the number of molecules in the light path, i.e., to the concentration (c) and the path length (1). The law may be expressed mathematically as ... 

During a fourth-year undergraduate research project at the University of Toronto, Dr. R.J. Leroy pursued an answer to the following question If you use photodissociation to separate iodine molecules into atoms, what fraction of the light is absorbed, and how does that fraction depend on the colour (frequency) of the light and on the temperature of the molecules (Photodissociation is a process that involves the use of light to decompose molecules.)... 

The reflectivity of silicon at 633 nm is 35% and the absorption coefficient is 3.8 x 10 m . Calculate the following qnantities for a 10 p,m-thick sample of silicon at this wavelength. Person 1 Calculate the fraction of incident light that is absorbed. 

It is important to note that each successive millimeter of path length of absorbing solution in a 1.0 cm cell absorbs not a constant amount but a constant fraction of the light that is incident upon it. However, with an absorbing layer of fixed path length, the absorbance, A, is directly proportional to the concentration of the absorbing solute. 

In solution, the fluorescence quantum yield light source, is defined as the fraction of absorbed incident radiation that is re-emitted as fluorescence ... 

Absorbance and transmittance are two important terms used in absorption measurement. If a beam of radiation of intensity P(> passes through a layer of solution, a part of the light is absorbed by the particles of the solution thus, the power of the beam weakens. The transmittance T of the solution is measured as the fraction of incident light transmitted by the solution. If the intensity of the transmitted light is I then transmittance is measured as,... 

When monochromatic light is incident upon an electrode, it will be absorbed if the energy of the photons is greater than that of the band gap. The resulting electric current produced depends upon the electrode potential. Correspondingly, a fraction of the light is reflected and the intensity of this light is potential dependent. 

The IMPS response is dominated by transport effects provided that the lifetime, r , of injected electrons is sufficiently long that all electrons reach the back contact (rD < t ). In this case, the dc value of is determined by the fraction of incident light that is absorbed, and the characteristic frequency is determined by the mean electron transit time rD. The effect on the IMPS response of reducing r is illustrated in Fig. 8.31. The dc... 

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