A universal approach to spin selective core-hole-clock measurement demonstrated for Ar/Co(0001)

Using monolayers of argon physisorbed on in-plane magnetized thin cobalt films, we demonstrate that spin selective core-hole-clock measurements become possible by spin filtering the decay electrons, even if spin selective excitation of the core resonance is excluded. We foresee a wide range of applications for this approach to spin selective investigations of electron transfer dynamics, in particular for organics in contact with ferromagnetic materials as in systems of molecular spintronics.