Incident monochromatic

Fig. 4-9. This diagram shows the intensity variation with angle for a rock salt crystal in the region near the Bragg angle, 0q, for an incident monochromatic beam. The area under the mosaic crystal curve could be thirty times greater than the ideal. (After Renninger, Z. Krist. 89, 344.)...

The incident monochromatic photon-to-current conversion efficiency (IPCE), also called external quantum efficiency, is defined as the number of electrons generated by light in the external circuit divided by the number of incident photons as a function of excitation wavelength. It is expressed in Equation (7).29 In most cases, the photoaction spectrum overlaps with the absorption spectrum of the sensitizer adsorbed on the semiconductor surface. A high IPCE is a prerequisite for high-power photovoltaic applications, which depends on the sensitizer photon absorption, excited state electron injection, and electron transport to the terminals ... 

The photocurrent action spectra of these complexes show broad features covering a large part of visible spectrum, and display a maximum at around 550 nm, where the incident monochromatic IPCE exceeds 85%. These hydrophobic complexes show excellent stability towards water-induced desorption when used as CT photosensitizers in nanocrystalline Ti02-based solar cells.62... 

Figure 2.7 Si 220 reflection with a plane incident monochromatic wave, (a) duMond diagram showing the angle at which the wave will diffract, and a 2° angular aperture that easily allows it to pass, (b) the corresponding real-space geometry...

All the above techniques use incident monochromatic radiation, usually focus in one or two dimensions. However for cases a) and d) the reduction of radiation damage and more particularly in kinetic crystallography the use of polychromatic data collection is yielding promising results. This technique makes combined use of the intensity and collimation of the SR beam with a large wavelength spread for Laue data colla tion from protein single crystals. 

The photoionization efficiency is defined as the number of ions, produced by one incident photon on unit path length at unit gas pressure. The curves in Figures 3-6 represent spectral efficiency curves. On them the ratio of the measured photocurrent to the number of incident monochromatic photons is plotted as function of the photon energy (in e.v.). At the low pressure used in the mass spectrometer (< 10 3 torr) the efficiency curves are proportional to the photoionization cross-section curves.3... 

IPCE Incident monochromatic photon-to-current conversion efficiency... 

The incident monochromatic photon-to-current conversion efficiency (IPCE) is plotted as a function of excitation wavelength. The IPCE value in the plateau region is 80% for complex 2, while for complex 25 it is only about 66%. In the red region, the difference is even more pronounced. Thus, at 700 nm the IPCE value is twice as high for the fully protonated complex 2 as compared to the deprotonated complex 25. As a consequence, the short circuit photocurrent is 18-19 mAcrn-2 for complex 2, while it is only about 12-13 mA cm-2 for complex 25. However, there is a trade-off in photovoltage, which is 0.9 V for complex 25, as compared to 0.65 V for complex 2. Nevertheless, this is insufficient to compensate for the current loss. Hence, the... 

Because the incident monochromatic light is absorbed, reflected, and scattered by the opaque layer material, the theoretical relationship between amount of absorption and amount of substance does not follow the simple Beer-Lambert law that is valid for solutions. The Kubelka-Munk equation is the most accepted theoretical relationship for TLC, but its use is not necessary because of the ability of densitometer software to handle empirical nonlinear regression functions. 

Here /g is the intensity of incident monochromatic radiation, I is the intensity of radiation at a distance I cm, and e is the decadic molar extinction coefficient of an absorbing species (concentration, c mole. 1 ). This law is strictly valid only if molecular interactions are unimportant at all concentrations. Deviations occur for a variety of reasons this means that the validity of the law should be checked under the particular experimental conditions. An initial determination of the absorption spectrum of the compound under investigation is obligatory. This produces immediate qualitative information, particularly about the usefulness of the source of radiation. Banded, diffuse or continuous spectra give direct information about the complexity and variety of primary processes that may occur. Further information will be gained from the effect of radical traps such as Oj or NO, and of various energy transfer agents. 

Incident monochromatic photon flu (at wavelength V) moles, of photons liter"1 "1)... 

The expression A - B (1< >) signifies that overall a photosensitive reagent A is transformed under irradiation into a product B. is the incident monochromatic photon flux (in moles of photons per liter per second) at the irradiation wavelength X. In the following discussion, the prime ( ) always indicates the irradiation wavelength. Abs is the total absorbance of the solution at this wavelenth15 ... 

An incident monochromatic beam scattered by a sample is analyzed with a detector at a general position in space (see Fig. 2). Incident and scattered neutrons are regarded as plane waves whose wavevectors are ki and kf, respectively. ( jfco = 27t/Ao and kf = 2tt/ /, where Ao and A/ are the incident and scattered wavelengths, respectively.) The momentum transfer vector is Q — ki kf. 

We can write tlie polarization of a sum-frequency generation process w, = -t-tu, for two incident monochromatic waves at cui and roj as... 

The intensihes of strong bands in Raman spectra are usually at least 10 -fold weaker than the intensity of the incident monochromatic beam. 

If an array of crystals are randomly oriented with respect to an incident monochromatic beam, then a series of concentric rings are produced. The spacings of the rings indicates the lattice dimensions and their sharpness the degree of crystallinity of the sample. Rather than record a series of concentric rings on a photographic plate, the traces are now instrumentalised (Figure 4.9). 

Let us stress that the operational definition of the quantum phase of radiation [47] is also based on the use of bilinear forms in the photon operators. In the simplest form, the idea of the operational approach to the phase difference can be illustrated with the aid of the two-port interferometer shown in Fig. 11 (see Refs. 14 and 47 for more detailed discussion). The two incident monochromatic (or quasimonochromatic) light beams are combined by a symmetric beamsplitter oriented at 45° to each beam. The resultant intensities emerging from each output port are measured by the two photodetectors connected with a comparator (computer) as in the Hanbury-Brown-Twiss interferometer [85] (also see Refs. 14, 15, and 86). Following Noh et al. [47], we denote by a and 2 the photon annihilation operators, describing the field at the two input ports, and by a and 04 the corresponding operators at the two output ports. Then... 

Let us first consider what happens when an incident monochromatic beam [c.f. Eq. (3.2.1)] impinges on a single molecule which has an anisotropic polarizability specified by a polarizability tensor a. The incident light induces a dipole moment... 

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