CHEMICAL-CHANGE OF NITROSYLPENTACYANOFERRATE(II) DURING XPS MEASUREMENTS - IDENTIFICATION OF THE IRRADIATED PRODUCT BY DV-X-ALPHA MOLECULAR-ORBITAL CALCULATIONS

A spectral change of the core and valence band levels for sodium nitro sylpentacyanoferrate(II) dihydrate, Na-2[Fe(NO)(CN)(5)]. 2H(2)O, has b een observed during XPS measurements. The fresh sample had two peaks f or N 1s at 402.9 and 398.8 eV, one peak for Fe 2p(3/2) at 710.6 eV and one peak for Fe 2p(1/2) at 723.5 eV. The irradiation of the sample by X-ray and e(-) flood decreased the intensity of the N 1s signal at 40 2.9 eV, and gave new peaks in 708.4 and 721.5 in the Fe 2p region. Irr adiation also gave a peak of 1.5 eV in the valence band. The experimen tal results and a molecular orbital calculation by the DV-Xa SCF proce dure suggest that the irradiated product of the compounds is [Fe(CN)(5 )](3-) or [Fe(CN)(5)(OH2)](3-).