Vibrational and mossbauer spectra of Mn(Fe(CN)5NO)m complexes (M = ScIII, YIII, LaIII, FeII). A normal coordinate treatment

The influence of the outer sphere cations (Sc, Y, La, Fe) on the position and intensity of the [Fe(CN)₅NO]^2- vibrational bands as well as on the Mössbauer parameters is explored with ab initio calculations and normal coordinate analysis (NCA). The B3LYP calculations show redistribution of the electron density caused by the second coordination sphere of Fe. Changes in the force field and in the vibrational eigenvectors are obtained with NCA. Both the theoretical and experimental results are combined in order to present a coherent picture of the role of the second coordination sphere.