Spectral dispersion angular

Several general observations can be made from the spectra and the calculated ESR parameters. First, the Na+- smectites possess narrower resonance line widths than the Ca +-smectites, with the exception of the saponite. Since Ca +-smectites, unlike Na+ -smectites, do not disperse into individual platelets in aqueous suspension, the Na+-smectite films formed by drying suspensions onto a smooth flat surface have the silicate surfaces more perfectly oriented in the plane of the film. As a result, less angular variation of the z-axis of Cu + relative to the plane of the film would narrow the spectra. One can see evidence of hyperfine splitting in the gj component of the Na+-smectite spectra, but not in the Ca +-smectite spectra. Saponite, unlike the other smectites, has very similar spectral linewidths for the Na+ and Ca + form (Figure 16). Since this Na+-saponite sample does not disperse completely in water (Table II), the alignment of Na+-saponite platelets in the clay film may be no better than that of the Ca +-saponite. 

Figure 6.8. ARUPS spectra measured for k along the F-Z direction T 61 K, 25 eV). The energy and angular resolution amounted to 60 meV and 1°, respectively. The thin lines indicate the dispersion of the spectral features. Reprinted with permission from R. Claessen, M. Sing, U. Schwingenschlogl, P. Blaha, M. Dressel and C. S. Jacobsen, Physical Review Letters, 88, 096402 (2002). Copyright (2002) by the American Physical Society.

For a normal spectrum the angular deviation of spectral lines from the normal is very small and d92/dX = const thus there is a linear relation between angular dispersion and wavelength for the normal spectrum. It also should be noted that the dispersion increases as the order , that is, a second-order spectrum has twice the dispersion of one of first order, etc. 

Let us consider the attainable spectral resolving power of a spectrometer. When passing the dispersing element (prism or grating), a parallel beam composed of two monochromatic waves with wavelengths X and X -f AA. is split into two partial beams with the angular deviations 9 and 6> + A6> from their initial direction (Fig. 4.8). The angular separation is... 

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