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Title: A first-principle calculation of the XANES spectrum of Cu{sup 2+} in water

The progress in high performance computing we are witnessing today offers the possibility of accurate electron density calculations of systems in realistic physico-chemical conditions. In this paper, we present a strategy aimed at performing a first-principle computation of the low energy part of the X-ray Absorption Spectroscopy (XAS) spectrum based on the density functional theory calculation of the electronic potential. To test its effectiveness, we apply the method to the computation of the X-ray absorption near edge structure part of the XAS spectrum in the paradigmatic, but simple case of Cu{sup 2+} in water. In order to keep into account the effect of the metal site structure fluctuations in determining the experimental signal, the theoretical spectrum is evaluated as the average over the computed spectra of a statistically significant number of simulated metal site configurations. The comparison of experimental data with theoretical calculations suggests that Cu{sup 2+} lives preferentially in a square-pyramidal geometry. The remarkable success of this approach in the interpretation of XAS data makes us optimistic about the possibility of extending the computational strategy we have outlined to the more interesting case of molecules of biological relevance bound to transition metal ions.
Authors:
 [1] ; ; ;  [2] ;  [3] ;  [2] ;  [3] ;  [3]
  1. CNR–Institute for Chemistry of Organometallic Compounds, Sesto Fiorentino 50019 (Italy)
  2. INFN, Rome “Tor Vergata,” Rome 00133 (Italy)
  3. (Italy)
Publication Date:
OSTI Identifier:
22489651
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 143; Journal Issue: 12; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ABSORPTION; ABSORPTION SPECTROSCOPY; COMPARATIVE EVALUATIONS; COPPER IONS; DENSITY FUNCTIONAL METHOD; ELECTRON DENSITY; SIGNALS; SIMULATION; SPECTRA; TRANSITION ELEMENTS; WATER; X RADIATION; X-RAY SPECTROSCOPY