Optical constant, definition

Fig. n.8 The structure of an OLED with three organic layers and a dielectric cover layer. HTL refers to the hole transport layer, EML to the emission layer, ETL to the electron transport layer. N, and k, are the optical constants of the layers (for their definitions, see Sect. 11.2.3). The dielectric is an antireflection layer. After [6, 10]. 

Definition (optical constants) The refractive index, w, and the extinction coefficient, A , which together determine the complex refractive index N = n - ik of an absorbing medium. [41]... 

The classification of microemulsions based on size is not adequate. Whether a system is transparent or translucent depends not only on the size but also on the difference in refractive index between the oil and the water phases. A microemulsion with small size (in the region of 10 nm) may appear translucent if the difference in refractive index between the oil and the water is large (note that the intensity of light scattered depends on the size and an optical constant that is given by the difference in refractive index between oil and water). Relatively large microemulsion droplets (in the region of 50 nm) may appear transparent if the refractive index difference is very small. The best definition of microemulsions is based on the application of thermodynamics, as discussed below. 

An extension of optical treatments to include anisotropy in the optical constants provides a means to estimate chain orientation and surface concentration from reflection-absorption intensities. Models of this kind are based on a definition of optical constants as in Figure 1. The ambient superphase and liquid sublease are isotropic, and the monolayer has the indicated anisotropic optical constants. Fina and Tung (26) originally used such a model to predict the dependence of the reflection-absorption of a monolayer on the chain orientation. The reflected amplitudes for a three phase system are found from the well known relationship ... 

K is a constant containing all the optical parameters for light, electron density fluctuations for X-rays and scattering length difference for neutrons. The exact definitions of K are given as ... 

Nature furnishes us with a certain number of hydrated silicates which mineralogists call zeolites the dehydration of certain hydrates offers curious peculiarities analcime, for instance, may be completely dehydrated without any sudden variation in form or optical properties of the crystals being observed Georges Friedel has shown that analcime had not, at a given temperature, an invariable dissociation tension let us suppose the temperature constant in a first equilibrium state the tension of the water vapor which exists in equilibrium above the crystals has the value P remove a portion of this water vapor the analcime will undergo a certain dehydration and the tension of the water vapor will increase, but only to a value P, less than P and BO on analcime is therefore not a definite hydrate, but only a solid solution in which water is mixed with an anhydrous silicate. 

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