Molecular refraction coefficient

The specific refraction 8 is 0-2732 and the refraction equivalent 49-50. The absorption of light by a 0-0lN-solution of arsenic trichloride in N-hydrochiorie acid has been examined,9 and it has been observed that the molecular extinction coefficient varies from 5 to 30 as the wavelength of the incident light decreases from 3570 to 2270 A. 

Indicator variable for which the value is 1 for saturated ring compounds otherwise the value is zero Indicator variable for which the value is 1 for compounds with substituents at the 5- or 6- position of 2-nitronaphtofur-ans and pyrenofurans otherwise the value is zero Molecular refractivity, which is a measure of the substituent bulk for any substituents that are next to the nitro group, negative coefficient indicates its detrimental effect toward log SOSIP... 

Other molecular properties have been also proposed to model the hydrophobic interactions. The parachor, which is related to the surface tension of a compound (139, 140) represents mainly the intermolecular interactions in a liquid. The Hildebrand-Scott solubility parameter, 6, (141) is related to intermolecular van der Waals forces and the closely related molar attraction constant, F, is obtained by multiplying 6 by the molar volume (142). The partition coefficient between two solvents can be obtained from the solubility parameters and the molar volumes of the solute and the solvents (193). This relationship is based on regular solution theory (194) and the assumption that the partial molar volumes of the solute is not different from its molar volume. Recently this has been criticized and a new derivation was proposed (195) in which the partial molar volumes are taken into account. The molar refractivity, MR, is related to dispersion forces and can be obtained as a sum of the partial molar refractivi-ties assigned to atoms and bonds (140, 143). These parameters have been compared (144) to establish their relative applicability to correlations with biological activity. The conclusion was that logP and molecular refractivity were the best parameters. Parameters obtained from high pressure liquid chromatography (144,... 

Besides the general phenomenon of an intensity increase due to the refractive index of the medium exceeding unity (29), there are instances of a wide change of the molecular extinction coefficient e, or the oscillator... 

An empirical molecular descriptor derived from a —> group contribution method based on molecular refractivity to predict activated carbon adsorption of 15 7 compounds [Abe, Tatsumoto et al, 1986]. This index was also applied to predict the —> soil sorption partition coefficient of the same 157 compounds [Okouchi and Saegusa, 1989 Okouchi, Saegusa et al., 1992]. 

FIGURE 15.1 Comparison of a set of physicochemical properties associated with the aromatic compounds benzene and thiophene. The properties include molecular weight (MW), melting point (mp), boiling point (bp), octanol/water partition coefficient (Log P), molecular refractivity (MR), and density (d). 

Lee et al. separated 18 L-amino acids by RP-HPLC. Binding energy ( b), hydrophobicity (log P), molecular refractivity (MR), polarizability (a), total energy (E ), water solubility (log S), connectivity index (%) of different orders and Wiener index (W) were also theoretically calculated. The retention factors with various physicochemical and structural properties of L-amino acids were represented. After investigating the effect of descriptors on the retention factors, the live major ones were found to be E y, MR, Et, V, and W. The correlation coefficient was more than 0.95. 

Infrared ellipsometry is typically performed in the mid-infrared range of 400 to 5000 cm , but also in the near- and far-infrared. The resonances of molecular vibrations or phonons in the solid state generate typical features in the tanT and A spectra in the form of relative minima or maxima and dispersion-like structures. For the isotropic bulk calculation of optical constants - refractive index n and extinction coefficient k - is straightforward. For all other applications (thin films and anisotropic materials) iteration procedures are used. In ellipsometry only angles are measured. The results are also absolute values, obtained without the use of a standard. 

Synthetic, nonionic polymers generally elute with little or no adsorption on TSK-PW columns. Characterization of these polymers has been demonstrated successfully using four types of on-line detectors. These include differential refractive index (DRI), differential viscometry (DV), FALLS, and MALLS detection (4-8). Absolute molecular weight, root mean square (RMS) radius of gyration, conformational coefficients, and intrinsic viscosity distributions have... 

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