Photon-induced magnetization reversal in theFe8single-molecule magnet

We use millimeter-wave radiation to manipulate the populations of the energy levels of a single crystal of molecular magnet ${\mathrm{Fe}}_8$. When continuous-wave radiation is in resonance with the transition from the ground state to the first excited state, the equilibrium magnetization exhibits a peak or dip whose field position varies linearly with the radiation frequency. Our results provide a lower bound of $0.17\mathrm{ns}$ for transverse relaxation time and suggest the possibility that single-molecule magnets might be utilized for quantum computation.