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All of the SMMs based EPR studies performed up to this point have been strictly based on the use of continuous wave microwave radiation. Although cw EPR spectroscopy has proven to be an excellent instrument for the understanding of the quantum nature of SMMs, it fails in providing information about relaxation phenomena associated with the interaction of the spin and the environment, which is the center of our attention in regards of this project. On the contrary, pulse EPR spectroscopy, where short pulses of high power microwave radiation are sent to the sample, has been established as a basic tool for an enhanced characterization of a broad spectrum of magnetic molecules. This time-domain technique allows, among others, the study of relaxation phenomena in molecular magnetism, giving information about spin-lattice (T1) and spin-spin (T2) relaxation times, which are of critical importance in the understanding of the local crystallographic environment of a given compound, revealing the geometry and symmetry of its chemical and structural configuration. However, this technique has never been employed to study the quantum dynamics of the spin in SMMs. This is in part due to the limitation imposed by commercial pulse EPR spectrometers, designed to work at low frequencies and magnetic fields and with substantially large samples
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