  Inelastic neutron scattering for temperatures below 30 K from a powder of
LiZn2Mo3O8 demonstrates this triangular-lattice antiferromagnet hosts
collective magnetic excitations from spin 1/2 Mo3O13 molecules. Apparently
gapless (\Delta < 0.2 meV) and extending at least up to 2.5 meV, the low energy
magnetic scattering cross section is surprisingly broad in momentum space and
involves one third of the spins present above 100 K. The data are compatible
with the presence of valence-bonds involving nearest-neighbor and
next-nearest-neighbor spins forming a disordered or dynamic state.
