INDEX electronic effects

An applied electric field can also change a material s linear susceptibility, and thus its refractive index. This effect is known as the linear electro-optic (LEO) or Pocket s effect, and it can be used to modulate light by changing the voltage applied to a second-order NLO material. The applied voltage anisotropically distorts the electron... 

Having resolved the molecular perception problem and achieved a unique representation of all atoms, bonds, and rings in the molecule, the second major step is the definition of the most useful measure for local similarity of atoms and atomic environment. For the purpose of COSMO/rag, we need to achieve the state that atoms are considered as most similar, if their partial molecular surfaces and surface polarities, i.e., polarization charge densities, are most similar. But since the latter is not known, at least for the new molecule under consideration, we have to ensure that the local geometries and the electronic effects of the surrounding atoms are most similar. Obviously, two similar atoms should at legist be identical with respect to their element and their hybridization. Turning this information into a unique real number, a similarity index of the lowest order (zeroth order) can be defined for each atom from the atom element numbers and... 

The electron effective mass in GaN is now reasonably well established by cyclotron resonance measurements [14-16] asm, = (0.22 0.0 l)m, and the low frequency dielectric constant (appropriately averaged spatially) e(0) = 9.5 0.2, from infrared refractive index and optic phonon energy measurements [17]. We can therefore derive a reliable value for the hydrogenic donor ionisation energy of EDH = (33.0 1.5) meV which compares well with IR absorption measurements, giving Ed = (35 1) meV [18] (see below). The discrepancy is readily explained in terms of a small chemical shift. 

IlMei et al. (39) derived the VHSE5 composite index of electronic effects. This scale (Vectors of Hydrophobic, Steric, and Electronic properties) was derived from principal components analysis of 50 different physico-chemical variables. 

Fibonacci numbers -> symmetry descriptors (O Merrifield-Simmons index) fieid effect -> electronic substituent constants fieid-fitting alignment -> aiignment ruies... 

Third-harmonic generation (THG), in which a fundamental beam at frequency 0) is converted to frequency 3a), is a technique frequently used to measure to, w, cS) of organic molecules or polymers. This technique is rather accurate and sensitive even to small y (-3a> o>, w) values. Only electronic effects contribute to THG. Therefore, thermal or stray-light effects, which can be troublesome in measurements based on the intensity-dependent refractive index, do not contribute to o), to, w). However, important slower contributions to... 

Subsequently, Jia et al calculated the conductance for the different structures. The conductance is quantized and it has turned out to be useful to plot the square root of the conductance as a function of a running integer that enumerates the different conductance values. Such a plot is shown in Fig. 44. The fact that the slope changes for an index value of 6 is interpreted as indicating a transition below which the stability of the nanowires is dictated by electronic effects, whereas atomic packing effects determine the stability for larger nanowires. 

The second method to be discussed, MSA, was introduced in 1980. It explicitly assumes that the shapes of the molecules provide information about the shape of the receptor cavity.Pairwise similarities and dissimilarities are calculated between a reference structure and the other compounds of the data set. Typically, biological potency is correlated with one shape index plus conventional QSAR descriptors for lipophilicity and electronic effects. 

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