Dipolar mobility parameter

MHz range is, in general, optimum for measuring both the ionic mobility parameter a and the dipolar mobility parameter t. 

Using the measured CHI data of the model compounds we can set up a correlation equation to express the H-bond acidity (a), H-bond basicity (f) and the polarisability-dipolarity (n) parameters by the CHI values obtained on a particular stationary phase with a particular mobile phase. The plot of the database descriptors as a function of the estimated ones based on the measured CHI values can be seen in Figs. 12.20-12.22. The best equations for the estimation of the descriptors are also shown in the figures. It can be seen that the CHI values obtained on Luna C-18 columns with acetonitrile and trifluoroethanol gradients are used for the fi and the ir calculations. The CHI values... 

Thus, subsequent Fourier transformation in l yields a spinning sideband pattern, with sidebands separated by coR and intensity distribution determined by d. Simulation of the sideband pattern then yields d, the dipolar coupling constant, or in a mobile system undergoing rapid uniaxial motion, <4ff, where de is the motionally averaged dipolar coupling parameter, given for uniaxial motion by... 

Valko et al. [37] developed a fast-gradient RP-HPLC method for the determination of a chromatographic hydrophobicity index (CHI). An octadecylsilane (ODS) column and 50 mM aqueous ammonium acetate (pH 7.4) mobile phase with acetonitrile as an organic modifier (0-100%) were used. The system calibration and quality control were performed periodically by measuring retention for 10 standards unionized at pH 7.4. The CHI could then be used as an independent measure of hydrophobicity. In addition, its correlation with linear free-energy parameters explained some molecular descriptors, including H-bond basicity/ acidity and dipolarity/polarizability. It is noted [27] that there are significant differences between CHI values and octanol-water log D values. 

TheD term accounts for part of the effects of solution enthalpy. Enthalpy of mixing results when the solute-solvent interaction force is different from the solute-solute and the solvent-solvent interactions. Intermolecularforces can be further characterized as dispersion, dipolar, and hydrogen-bond forces. In the mobile order solubility approach, dispersion and dipolar forces were not separated. The effects of these two forces on solubility were expressed in terms of modiLed solubility parameters, S andSj. The relationship between solubility and solubility parameters can be derived in the... 

Fig. 2 A nitroxide scan on KcsA. (a) Linear representation of the putative transmembrane topology of KcsA and the nitroxide scan (linear scale with arrows), (b) Room temperature CW EPR spectra for two regions in TMl and TM2. Multiple nitroxide components are highlighted by red arrows in selected spectra, (c) Mobility and accessibility plots. Periodical pattern are visible. On the right, helical wheel representation showing the trends of the EPR parameters extracted from the spectra in a polar coordinate representation, (d) Example of dipolar broadening on position 108, and effect of underlabeling on the spectral shape. On the right the shortest distance...

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