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Molar polarization refraction

The connection between the molar polarization Pm and the molar refraction Rm is through Maxwell s theory of electromagnetism, according to which e = (at low-frequency fields). This is the basis for considering the molar refraction a measure of polarizability. [Pg.390]

The molar polarization of the solvent, P, is given by the Clausius-Mosotti expression P = V(s - l)/(s + 2), similar to the expression for the molar refraction. It is the molar polarization that relates the relative permittivity to the dipole moment p and the polarizability a ... [Pg.173]

The molar refraction RD and molar polarization P per unit volume, i.e., the functions f (nD) = ( D -1)/ + 2) and g(e) = (s -l)/(s + 2), or similar functions with 1 replacing 2 and/or 2 multiplying nD and s in the denominators, have often been employed in correlations of chemical properties of solvents with their physical, optical, and electrical properties. [Pg.173]

For each solution studied, calculate k from Eq. (30) as well as p and X2. Plot k and p versus the mole fraction of solute X2, and draw the best straight lines through your points see Eqs. (18) and (19). Obtain the slopes a and b, the intercepts should agree with the pure solvent results. Using Eq. (20), calculate F2M, the molar polarization at infinite dilution. Estimate from Eq. (21) using the literature value of the refractive index of the solute / 2, and obtain... [Pg.345]

The permanent dipole moment /tt of a polar molecule is determined in Exp. 29 from measurements of the dielectric constant of a solution containing such molecules as solute. In the present experiment, the permanent dipole moment of a gas molecule is determined. The orientation polarization can be separated from the distortion polarization by means of measurements at more than one temperature, making use of the fact that the former is temperature dependent while the latter is not. An alternative method, which is recommended for this experiment, is to obtain the orientation polarization by subtracting from the molar polarization the distortion polarization as determined separately from the refractive index of the gas, which is determined by means of a laser interferometer. Thus the molar polarization needs to be determined at only one temperature. [Pg.347]

Here V is the molal volume of the liquid, N is Avagadro s number, K the. Boltzmann constant, T the absolute temperature, and is the angle between the vectors jj, and Ji. ag is the polarizability of the molecules in the liquid it can be determined from the refractive index. For highly polar substances is small compared to the second term in the parenthesis. The high dielectric constant of water is well accounted for by equation (47) on the basis of the known dipole moment of water, and the orientation of the water molecules relative to one another. The molar polarization of the liquid is defined in terms of the polarizability and the dipole moment of the molecules by equation (47). In a solution containing several components equation (47) becomes... [Pg.158]

Using the data given below for dilute solutions of nitromethane in benzene, calculate the molar polarization and refraction of the solute in the limit of infinite dilution. Then, estimate the dipole moment of nitromethane on the basis of the Debye model. [Pg.159]

Fig. 4.2 Plot of the molar polarization Pml and molar refraction R 2 for nitromethane against its mole fraction in benzene. Fig. 4.2 Plot of the molar polarization Pml and molar refraction R 2 for nitromethane against its mole fraction in benzene.
Table 9.3. Experimental and predicted values of the molar polarization PLL and the molar refraction RLL in cc/mole, and the effective dipole moment (I at room temperature in debyes,... Table 9.3. Experimental and predicted values of the molar polarization PLL and the molar refraction RLL in cc/mole, and the effective dipole moment (I at room temperature in debyes,...
Maryott, A. A., and Buckley, E, U. S. National Bureau of Standards Circular No. 537, 1953. A tabulation of dipole moments, dielectric constants, and molar refractions measured between 1910 and 1952, and used here to determine polarizabilities if no more recent result exists. The polarizability is 3/(4ttA/ ) times the molar polarization or molar refraction, where is Avogadros number. The value 3/(4tiA/ ) = 0.3964308 x 10 cm was used for this conversion. A dagger (t) following the reference number in the tables indicates that the polarizability was derived from the molar refraction and hence may not include some low-frequency contributions to the static polarizability these static polarizabilities are therefore low by 1 to 30%. Hirschfelder, J. O., Curtis, C. E, and Bird, R. B., Molecular Theory of Gases and Liquids, Wiley, New York, 1954, p. 950. Fundamental information on molecular polarizabilities. [Pg.1669]

Molar volume MV, molar refractivity MR, and parachor PA are theoretically and practically closely interrelated parameters (eqs. 33 — 35 MW = molecular weight, Q = density, n = refractive index y = surface tension) [285]. Another related parameter is the molar polarization P (dielectric constant 8 instead of the n term in eq. 34) [286]. [Pg.40]

The high-fiequency contribution to the molar polarization. at 273 K may be calculated from the refractive index ... [Pg.363]

The electronic polarization (P ) of a molecule is not only useful to calculate the atomic component of the molar polarization and the dipole moment, but is of independent interest for studying the bonding type and structure of a substance. Among chemists the Pe determined according to Eq. 11.14 is commonly known as the refraction , R, and is expressed in non-SI units, cm /mol, whereas physicists prefer to use polarizability a, expressed in A, so that formally a = 0.3964 R (a is also expressed in atomic units, 1 a. u. = 0.148185 A ). For uniformity, is measured with the 589 nmNa line (Ru) or is extrapolated to infinitely long waves (Poo), unless the entire dispersion spectrum of RI is determined. [Pg.489]

Numerous authors have devised multiple linear regression approaches to the eorrelation of solvent effects, the intent being to widen the applieability of the eorrelation and to develop insight into the moleeular factors controlling the eorrelated proeess. For example, Zilian treated polarity as a eombination of effeets measured by molar refraction, AN, and DN. Koppel and Palm write... [Pg.443]

The apparent molar volume of interfacial water in AOT-reversed micelles is lower and its refractive index is greater than that of pure water. These findings, together with other experimental evidence, emphasize that these water molecnles are destructured, immobilized, and polarized by the ionic head of AOT [2,84,89]. In particular, it has been reported that the... [Pg.481]

In the equation s is the measured dielectric constant and e0 the permittivity of the vacuum, M is the molar mass and p the molecular density, while Aa and A (po2) are the isotope effects on the polarizability and the square of the permanent dipole moment respectively. Unfortunately, because the isotope effects under discussion are small, and high precision in measurements of bulk phase polarization is difficult to achieve, this approach has fallen into disfavor and now is only rarely used. Polarizability isotope effects, Aa, are better determined by measuring the frequency dependence of the refractive index (see below), and isotope effects on permanent dipole moments with spectroscopic experiments. [Pg.393]

Zhao and coworkers [53] also constructed a linear model using the Abraham descriptors. The MLR model possesses good correlation and predictability for external data sets. In this equation, E is an excess molar refraction (cm3/mol/ 10.0) and S the dipolarity/polarizability, A and B are the hydrogen bond acidity and basicity, respectively, and V is the McGowan characteristic volume (cm3/ mol/100). The large coefficients of A and B indicate too polar molecules having poor absorption. [Pg.112]


See other pages where Molar polarization refraction is mentioned: [Pg.348]    [Pg.68]    [Pg.199]    [Pg.158]    [Pg.332]    [Pg.332]    [Pg.167]    [Pg.360]    [Pg.3]    [Pg.37]    [Pg.68]    [Pg.75]    [Pg.27]    [Pg.24]    [Pg.69]    [Pg.404]    [Pg.255]    [Pg.445]    [Pg.615]   
See also in sourсe #XX -- [ Pg.413 ]




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