The high magnetic field problem

The full complexity of the many-body problem appeared in the previous example. A simpler situation would clearly be to restrict ourselves to a a 

1 In this respect, the highly-correlated, many-electron atom is similar to the situation encountered in nuclear physics, where there are many dynamical variables and there exists no simple semiclassical limit. Random matrix theory can be a useful framework, but the word chaos is not easy to define in this context. 

A hint that such a possibility exists was provided by the example of molecular spectra (see section 2.32) where the breaking of symmetry was shown to have a dramatic effect on the apparent complexity of spectra (see in particular figs. 2.16 and 2.17). 

We note in passing that this definition of a strong field is not the one found in textbooks, which relates to the relative strengths of the Zeeman splitting and multiplet structure (the Paschen-Back effect). A field capable of inducing angular-momentum uncoupling can still be a weak field under the present definition.2 

The first experiment in which the strong magnetic field regime was 

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There are, however, difficulties in this approach. These difficulties are not connected with the high magnetic field problem rather, they are... 

Diffusion of the ion population in the X-Y plane will depend upon the ion density (space-charge effects) and the strength of the applied magnetic field. Under conditions of high vacuum and in the absence of space-charge effects, diffusion of the ion population in the X-Y plane does not impose any serious problems for ion detection. That is, the radio-frequency signal... 

Fig. 4 shows another approach to the same problem. Here the energies of the four electronic pair states are plotted versus the radical pair distance for a certain hypothetical nuclear spin configuration and for high magnetic field. The... 

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