Evidence of Low-Energy Singlet Excited States in the Spin-1/2 Polyhedral Clusters {Mo${}_{72}$V${}_{30}$} and {W${}_{72}$V${}_{30}$} with Strongly Frustrated Kagomé Networks

T. Kihara, H. Nojiri, Y. Narumi +5

Magnetization, specific heat, and electron spin resonance (ESR) measurements are carried out to clarify the low-energy excitations for the S = 1/2 polyhedral clusters {Mo${}_{72}$V$_…