Closed shell molecular
structures are under normal conditions time-reversal
invariant. Experimental evidence points, however, toward that this
invariance may be locally violated when the structure is in contact
with a particle reservoir. The mechanisms behind such local symmetry
breaking are not clear by any means. By considering a minimal model
for a closed shell structure, here we propose that the symmetry breaking
may result from a combination of internal and/or external interactions.
It is shown that a magnetic moment of a localized electron level can
be generated and maintained under the influence of such a combination.
The theoretical results should cast new light on the mechanisms that
may form magnetic properties in molecular compounds.