  A multi-high-frequency electron paramagnetic resonance method is used to
probe the magnetic excitations of a dimer of single-molecule magnets. The
measured spectra display well resolved quantum transitions involving coherent
superposition states of both molecules. The behavior may be understood in terms
of an isotropic superexchange coupling between pairs of single-molecule
magnets, in analogy with several recently proposed quantum devices based on
artificially fabricated quantum dots or clusters. These findings highlight the
potential utility of supramolecular chemistry in the design of future quantum
devices based on molecular nanomagnets.
