  Electric fields represent an ideal means for controlling spins at the
nanoscale and, more specifically, for manipulating protected degrees of freedom
in multispin systems. Here we perform low-temperature magnetic far-IR
spectroscopy on a molecular spin triangle (Fe3) and provide the first
experimental evidence of spin-electric transitions in polynuclear complexes.
The co-presence of electric- and magnetic-dipole transitions, allows us to
estimate the spin-electric coupling. Based on spin Hamiltonian simulations of
the spectra, we identify the observed transitions and introduce the concept of
a generalized exchange qubit. This applies to a wide class of molecular spin
triangles, and includes the scalar chirality and the partial spin sum qubits as
special cases.
