Shape and giant resonances

Plots of quantum defects and of C(E) against energy are shown in fig. 5.14 (a) and (b). They demonstrate how this equation linearises QDT for a single channel containing a giant resonance. 

C(E) is a more appropriate function to plot than p itself, as it leads to a straight line plot from which Eq and To for the shape resonance can be determined. In the case shown, m = 1 because the well is just able to hold one bound state, as explained above the energy Eq obtained in this way from experimental data is consistent with the determination from Hartree-Fock calculations using a Morse potential. 

The isolated Beutler-Fano resonance appears, at first sight, to be the simplest situation which can give rise to a resonance in the continuum. In principle, the resonance can appear at any energy above the threshold, since resonance and continuum belong to distinct channels. Thus, there 

As explained above, resonances appear which do not owe their existence to the presence of two channels but could occur as broad features within a single channel even if correlations were turned off. They are not 

A distinction has already been made in section 5.19 between giant and autoionising resonances. In the present section, we point out further differences between them, and establish a simple connection to quantum scattering theory. 

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