MOSSBAUER PARAMETERS OF THE 2 LONG-LIVED METASTABLE STATES IN NA2[FE(CN)5NO]CENTER-DOT-2H2O SINGLE-CRYSTALS

We have measured the quadrupole splitting, isomer shift and line broad ening of the ground and two metastable states in Na2[Fe(CN)5NO].2H2O s ingle crystals. Pure state II could be observed by Mossbauer spectrosc opy after irradiation of state I with light in the near infrared spect ral region. The difference between the two nearly infinitely long-live d electronic states is shown. A possible change of the Fe(3d, 4s, 4p) electron densities is discussed on the basis of the Mossbauer paramete rs and the v(FeN) and v(NO) stretching vibrations. The resulting new o rbital population allows to explain the observed properties of state I . A rearrangement of the electron density due to state II would lead t o a contradiction with the vibrational behaviour of the molecule. The larger line width of both metastable states could not yet be interpret ed.