Low-temperature excitations in the magnetic Keplerate molecule ${\mathrm{Fe}}_{30}$ as calculated by linear spin-wave theory (SWT), modified linear SWT, and spin-level mean-field theory (SLMFT) are compared to recent inelastic neutron scattering results by Garlea et al. [Phys. Rev. B 73, 024414 (2006)]. SLMFT reproduces a part of the experimental spectrum rather well, but not all of it. SWTs yield a small fraction of the $E$-band excitations and hence are not capable of a complete description of the excitation spectrum.

• Received 11 September 2006

DOI:https://doi.org/10.1103/PhysRevB.75.012415