Figure 1

(a) INS intensity versus energy transfer at different temperatures for ${\mathrm{C}\mathrm{r}}_8$. Data recorded on IN6 with incident energy 2.35 meV at 2, 6, 12, 18, and 23 K (from back to front) are plotted as full circles, those with incident energy 4.86 meV at 12 and 21 K as open circles. Error bars are smaller than symbols. Open squares represent the MARI data at 2.5 K. For each curve, the background from the elastic peak and quasielastic contributions was fitted and subtracted from the data as shown in the inset for the IN6, 4.86 meV, 12 K data. The MARI data are enhanced by a factor of $\approx 10$ with respect to the IN6 data. (b) Energy spectrum of an octanuclear spin-$3/2$ Heisenberg ring versus total spin quantum number $S$ ($J=-1.46\mathrm{m}\mathrm{e}\mathrm{V}$). Arrows indicate observed transitions and their labeling. Values at states give exact energies in units of $|J|$ and $q$ in brackets. Values at arrows give the oscillator strengths $⟨n|S_i^z|m{⟩}^2$. Zero-field splitting of spin multiplets due to magnetic anisotropy is omitted.Reuse & Permissions

Figure 2

INS intensity at 2.5 K recorded on MARI with 15 meV incident neutron energy, integrated over the momentum range $0<Q<1.5{\AA }^{-1}$. The observed peaks were assigned as indicated. At low energies, the quasielastic peak dominates.Reuse & Permissions

Figure 3

Integrated intensity versus momentum transfer $Q$ for (a) the $0\to 1$ transition (insets: $1\to 2$ and $2\to 3$ transitions) and (b) the $0\to 1^{\prime }$ transition. Data were obtained on IN6 with 4.86 meV incident energy at 12 K. The solid lines represent the theoretical curves as calculated for (a) a transition with $q=0\to q^{\prime }=4$ and (b) the sum of transitions $q=0\to q^{\prime }=1$, 3, 5, and 7. Curves were scaled by a constant factor.Reuse & Permissions

Figure 4

Integrated intensity versus momentum transfer $Q$ for the $0\to 1$ transition as obtained on IN6 with 2.35 meV incident energy at 2 K. The solid line represents the theoretical curves as calculated for a transition with $q=0\to q^{\prime }=4$. The curve was scaled by a constant factor. The inset shows the intensity versus energy at 2 K. The peak at 0.7 meV corresponds to $Q=0.317{\AA }^{-1}$, the peak at 0.9 meV to $Q=0.344{\AA }^{-1}$.Reuse & Permissions