For any ultrasound of frequency v, the longitudinal wavelength X at the surface can be calculated from Equation 19.1, in which a is the surface tension of the liquid and p is the density of the liquid. [Pg.148]

As discussed in Section 5.10. the lifethnes calculated from the phase and modulation at a single frequency are only a arait values. The heterogMems decay of DAPI in water illustrates this effect. For an observaticm wavelength of470 nm and a modulation frequency of 100 MHz, [Pg.164]

What energy is associated with a 1H nmr transition The magnitude of this energy may be calculated from the relationship between energy and wavelength (frequency) of the absorbed radiation (Section 9-4). That is, [Pg.299]

Raman vibrational frequencies and intensities for both complexes 5 and 7 are compared in Table II. The relative Raman scattering intensities were calculated from the differential cross sections. For their evaluation we used the wavelength of 613.33 nm (105). Polarizabilities were calculated in the limit of a static perturbation. [Pg.87]

Note The values in Tables 2-1 and 2-2 are expressed as wavelengths and wavenumbers in air. The difference between Av (air) and Av (vacuum) is usually less than 1cm-1 and can be ignored in Raman spectroscopy. When molecular constants are calculated from absolute Raman frequencies, Av (air) must be converted to Av (vacuum). [Pg.99]

Spectroscopy Drug compounds absorb visible, infrared and UV radiation at frequencies that are characteristic of the compounds. Quantitative measurements can be calculated from the absorbance readings at specific frequencies or wavelengths. [Pg.253]

In the frequency-domain, the experimentally measured quantities are the frequency- (w) and wavelength- (X) dependent phase shift (0m(X,a>)) and demodulation factor (MnXX, )). For any assumed decay model (equation 1), these values are calculated from the sine (S(X,o>)) and cosine (C(X,w)) Fourier transforms. If we assume the decay kinetics are described by a simple sum of exponential decay times we have (24) [Pg.97]

The procedure consists of scanning the frequency response of a loaded resonator, whose unloaded characteristics are known. The permittivity and dissipation factor are calculated from the shift in peak frequency (or wavelength) and the Q-factor. [Pg.632]

We see from Fig. 26a (solid line 1) that the loss spectrum, calculated for our model with the same parameters, as chosen above (Table IX), exhibits resonance lines at the frequencies v < 50 cm-1. At v < 20 cm-1 the calculated solid loss curve 1, becoming nonresonant, coincides with the nonresonant dashed curve 2 calculated from Eqs. (72)-(74) with cfit = 2.35. Both loss s" curves 1 and 2 decrease linearly with v (in the log-log plot) in the interval from 50 to 0.1 cm-1 For further decrease of frequency the empirical dependence (72) exhibits a minimum at v about 0.1 cm-1 (viz, in the millimeter wavelength region). Near this minimum and at lower frequencies, our molecular model should not be applied. [Pg.409]

For FT-Raman spectrometers, an equivalent one-point calibration is more reliable because interferometers are less prone to mechanical errors. Nearly all interferometer designs include a well-defined reference wavelength (often a He-Ne laser at 632.8 nm), which is used to control data acquisition. In addition, observed FT frequencies are calculated from a large number of individual measurements, so minor mechanical jitter and random timing errors are averaged out. Provided the laser and reference frequencies are known accurately, an observed FT-Raman frequency is quite accurate, and the one-point calibration is usually adequate. [Pg.253]

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