Absorption quotient

In Equation 6-1, Io/I, usually an intensity ratio, is the quotient of the corrected average counting rate for the exposed substrate by that for the substrate covered with d cm of iron foil. The mass absorption coefficients of iron are m, a mean value for the incident (polychromatic) beam and g2, for the characteristic line being counted. The angles d and 02 are those made with the sample by the incident beam (30°) and by the emergent beam (60°), the beams being regarded as rays and... 

The constancy of the quotient in the last line of Table 7-2 is greatly improved over that in the line above the last, proving that Equation 7-5 holds. So far as we know, this is the first case in which the absorption effects for a series of solutions have been obtained so precisely. Examples of this kind place on a firmer basis the calculation of semiquantitative analytical results from measured intensities when the composition of the matrix (all of S but E, the element sought) in a sample is approximately known. For example, tungsten contents could be estimated from measurements of L7I intensity for sodium tungstate solutions even when other salts are present in the absence of such salts, tungsten contents... 

Inspection of the table shows that the quotient a/Wj e is in fact nearly constant that I changes much less rapidly than W e] and that the critical depth has doubled when the highest oxide is reached. All three conditions are reflections of the (positive) absorption effect that occurs in this binary system when iron is replaced by oxygen, which has a lower mass absorption coefficient. 

In 1951Castaing8 published results to show that an electron microscope could be converted into a useful x-ray emission spectrograph for point-to-point exploration on a micron scale. The conversion consisted mainly in adding a second electrostatic lens to obtain a narrower electron beam for the excitation of an x-ray spectrum, and adding an external spectrometer for analysis of the spectrum and measurement of analytical-line intensity. Outstanding features of the technique were the small size of sample (1 g cube, or thereabouts) and the absence of pronounced absorption and enhancement effects, which, of course, is characteristic of electron excitation (7.10). Castaing8 gives remarkable quantitative results for copper alloys the results in parentheses are the quotients... 

The effective lifetimes of all these excited states are determined by radiative as well as collisional deactivation, and which contribution is the more significant depends on pressure and transition probability. The simultaneous recording of the absorption and fluorescence spectra yields information about the ratio of radiative to collisioninduced nonradiative decays. This ratio is proportional to the quotient of total fluorescence from the excited level to total absorbed laser light. Such experiments have been started by Ronn oif... 

Kf = molal freezing-point depression constant Kt,= molal boiling-point elevation constant A = absorbance a= molar absorptivity b = path length c= concentration Q = reaction quotient /= current (amperes) q= charge (coulombs) f= time (seconds)... 

The absorption oscillator strength for CH4 was obtained24 from the forward scattering. The absolute ionization efficiency was then obtained by normalizing the quotient of the relative oscillator strength for ionization and absorption on a few absolute points obtained by a calibration procedure using a mixture of helium and neon. The ionization efficiency is unity from about 5 eV above threshold to the limit of the data at 80 eV. 

According to the Lambert-Beer law, the absorbance of the analyte at wavenumber is given by As = as-d-cs, and the absorbance of the internal standard at is A = aR-d-CR. Dividing the two equations yields Ar/Ar. The quotient of the values of the absorption coefficient remains constant at the used wavenumbers. If the concentration of the internal standard cr is constant, an overall constant K... 

The absorbance A is the logarithm (to the base 10) of the reciprocal of the transmittance (7), which in turn is the ratio of the intensity of the transmitted radiation I to the intensity of the incident radiation Iq. The absorptivity, a, is the quotient of the absorbance (A) divided by the product of concentration c in grams per liter of the substance and the absorption path length b in cm. The more commonly used molar absorptivity e is used when the concentration is in mol/L rather than g/L. 

The reason for the suppression of coalescence was sought in the repulsive electrical forces, which resulted from the electric potential difference at the G/L interface and resulted from the difference in ion concentrations there. Here Gibbs s absorption isotherm applies, which related the surface excess or deficiency to the differential quotient dcr/do ... 

Dispersive power is more constitutive than refractivity—a fact first recognized by Gladstone (1886, 1887) when investigating the quotients (w — nXl) d and M nXl — nX2)jd for additivity. Briihl (1891), using the Lorentz-Lorenz expression for the specific or molecular refractions, considerably extended the subject and prepared lists of atomic dispersions for the a and y hydrogen lines these were later revised by von Auwers and Eisenlohr. Tables such as those produced by the last-named author (1912, 1923) have always included values for Rp — Ra and Ry — Ra. Predicted dispersions are sometimes satisfactory when absorption wavelengths are well away from the visible region (e.g. from Table 2 Ry — Ra for acetyl chloride and pentyl alcohol are 0-44 and 0-64 cm3 the observed differences are 0 48 and 0-64 cm3 2 ... 

---