  The low-lying magnetic excitations in the dimer of single-molecule magnets
(Mn4)2 are studied by inelastic neutron scattering as a function of hydrostatic
pressure. The anisotropy parameters D and B04, which describe each Mn4 subunit,
are essentially pressure independent, while the antiferromagnetic exchange
coupling J between the two Mn4 subunits strongly depends on pressure, with an
increase of 42% at 17 kbar. Additional pressure dependent powder X-ray
measurements allow a structural interpretation of the findings.
