3978 be arranged in the order of a progressive change, for example, as Figures 4b, 4c (or 5a), and 5d, from a very qualitative point of view. It is possible that this progressive change in line shape may be coherently interpreted in terms of the relative energy values of zero-field splitting (D)and interdimer spin-exchange interaction (J’); namely, ID( >> 1J’I in Figure 4b, (Dl 1 J’( in Figure 4c, and /Dl
