Absorptivity, defined

LHE is the light harvesting efficiency or absorptance, defined as LHE = 1-10" where A is the absorbance, ( )inj is the quantum yield of charge injection, and r is the efficiency of transporting injected electrons in to the external circuit. Equation (3.6.26) can be written as ... 

A similar conclusion is reached using direct measurements of solar fluxes at the top of the atmosphere (TOA) and at surface sites under clear compared to cloudy conditions (e.g., Cess et al., 1995, 1996b Evans et al., 1995). Figure 14.51a shows the absorptance, defined as the fraction of the down-... 

In VCD, the differential absorption of left and right circularly polarized infrared radiation by a vibrational transition of a chiral molecule is observed. Equations (1-5) hold equally well for electronic and vibrational transitions, but in all transition moments, the electronic wave functions need to be replaced by vibrational (or vibro-nic) wave functions. In vibrational CD, the ratio of differential absorption to the infrared absorption, defined as... 

Disregarding multiple reflection, the absorptivity, defined as the photon current absorbed in a body of thickness d divided by the incident photon current is... 

The most common index of structure is oil absorption, defined as the minimum volume of oil (usually dibutyl phthalate) which will give, under conditions of controlled mixing, a mix having no voids . Spherically shaped powders pack closely, whereas branched-chain aggregates in a high-structure black give rise to... 

The part of a molecule that absorbs the light and is, therefore, responsible for its colour (whether in the visible or UV region) is called the chromophore, and the wavelength dependence of the absorption defines its absorption spectrum. Figure 7-3 illustrates the absorption spectrum of the three aromatic amino acids tryptophan, tyrosine and phenylalanine. 

For the absorption of two identical photons, 5ab = S ba- For planar aromatic molecules the two-photon transition is dominated by moments in the plane of the molecule. The relative absorption strengths for linear and circular polarized two-photon absorption define the parameter 11, which can be determined firom the integrated fiuorescence intensity for linear and circularly polarized absorption, as shown in Figure 11.4. 

Unlike traditional infrared spectroscopy, Raman is an emission phenomenon, and does not follow the laws of absorption defined earlier (Fig. 56). The intensity of a recorded spectral feature is a linear function of the concentration of the species present, and the intensity of the incident radiation. The measured intensity is not constant across the spectrum, and is limited by the response of the detector at the absolute wavelength of the point of measurement. As a result, with some detectors it is not possible to measure much beyond 3000 or 3500 cm . The InGaAs detector used in combination with the Nd YAG laser in a FT-Raman experiment is a case in point (the actual limit being influenced by the detector used, and whether it is cooled). Also, Raman scattering is not a linear eflcct, and varies as a function of where X is the absolute wavelength of the scattered radiation. While Raman intensity may be used analytically to measure the concentration of an analyte, it is necessary to standardize the output in terms of the laser intensity, the detector response, and the Raman scattering term. 

Actual rates of transfer across biological barriers are generally calculated fromEqs. (5) and (6). To calculate the rate coefficients of either equation, data consisting of concentration and volume versus time in both the compartment in which the drug is administered and in the receiving compartment are required. If the target compartment is the circulation, venous concentrations may be the only data available. In this case, the rate of transfer can be expressed as the product of the plasma concentration and the volume of distribution divided by the total dose administered. This produces a fractional rate of absorption defined by... 

The integrated intensity " has been expressed in a variety of units. It can be expressed as the integrated absorptivity, defined as... 

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