  An accurate experimental characterization of finite antiferromagnetic (AF)
spin chains is crucial for controlling and manipulating their magnetic
properties and quantum states for potential applications in spintronics or
quantum computation. In particular, finite AF chains are expected to show a
different magnetic behaviour depending on their length and topology. Molecular
AF rings are able to combine the quantum-magnetic behaviour of AF chains with a
very remarkable tunability of their topological and geometrical properties. In
this work we measure the $^{53}$Cr-NMR spectra of the Cr$_{8}$Cd ring to study
the local spin densities on the Cr sites. Cr$_{8}$Cd can in fact be considered
a model system of a finite AF open chain with an even number of spins. The NMR
resonant frequencies are in good agreement with the theoretical local spin
densities, by assuming a core polarization feld AC = -12.7 T/$\mu_B$. Moreover,
these NMR results confirm the theoretically predicted non-collinear spin
arrangement along the Cr$_{8}$Cd ring, which is typical of an even-open AF spin
chain.
