S mixing and quantum tunneling of the magnetization in molecular nanomagnets -: art. no. 207205

The role of S mixing in the quantum tunneling of the magnetization in nanomagnets has been investigated. We show that the effect on the tunneling frequency is huge and that the discrepancy (more than 3 orders of magnitude in the tunneling frequency) between spectroscopic and relaxation measurements in Fe-8 can be resolved if S mixing is taken into account.