(residual ZFS splitting from second-order couplings to higher states). This fit allows making the following assignments of the FIR and Raman spectra of 1: The magnetic-field dependent signals around 230 cm -1 (feature 1A) are associated with the intramultiplet transition between the zero-field split KDs of the lower quartet (Fig. ). The other features 1B and 1C are attributed to excitations from the ground KD of the quartet ground state to the two KDs of the the low-lying excited quartet state. In summary, the FIR and Raman spectra greatly support the model of a strong first-order interaction of two quartet states that leads to the extraordinarily strong ZFS of 1, because we actually spectroscopically observe transitions to the excited quartet state.