To successfully fit the copper XANES and EXAFS spectra of a copper-containing sample, it is usually desirable to record the XAS spectra of various copper compounds. Nevertheless, Cu(NO3)2 reference is very hygroscopic, and the fitting results can be misleading if Cu(NO 3)2 containing different amounts of H2O is used as reference. This study investigated the effect of water on the XAS spectrum of Cu(NO3)2 reference. The results, for the first shell (Cu-O), indicated that drier reference Cu(NO3)2 would have less coordination number. The interatomic distance was 1.95?? that was independent of the moisture content in Cu(NO3)2 reference, and there was a slight variation in the Debye-Waller factor for the Cu(NO 3)2 containing different moisture content. For the XANES spectra, it was found that the photon energy for the edge jump could be reduced by as great as 3-4?eV if Cu(NO3)2 was moisturized. This might have been due to the hydration effect on Cu2+. The white line showed that there was more empty d orbital for the copper in the moisturized Cu(NO3)2 than for the drier one. ? Physica Scripta 2005.
