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Title: Properties of aqueous nitrate and nitrite from x-ray absorption spectroscopy

Nitrate and nitrite ions are of considerable interest, both for their widespread use in commercial and research contexts and because of their central role in the global nitrogen cycle. The chemistry of atmospheric aerosols, wherein nitrate is abundant, has been found to depend on the interfacial behavior of ionic species. The interfacial behavior of ions is determined largely by their hydration properties; consequently, the study of the hydration and interfacial behavior of nitrate and nitrite comprises a significant field of study. In this work, we describe the study of aqueous solutions of sodium nitrate and nitrite via X-ray absorption spectroscopy (XAS), interpreted in light of first-principles density functional theory electronic structure calculations. Experimental and calculated spectra of the nitrogen K-edge XA spectra of bulk solutions exhibit a large 3.7 eV shift between the XA spectra of nitrate and nitrite resulting from greater stabilization of the nitrogen 1s energy level in nitrate. A similar shift is not observed in the oxygen K-edge XA spectra of NO{sub 3}{sup −} and NO{sub 2}{sup −}. The hydration properties of nitrate and nitrite are found to be similar, with both anions exhibiting a similar propensity towards ion pairing.
Authors:
; ;  [1] ;  [2] ;  [3] ;  [1] ;  [4]
  1. Department of Chemistry, University of California, Berkeley, California 94720 (United States)
  2. (United States)
  3. National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan (China)
  4. The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
Publication Date:
OSTI Identifier:
22493583
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 143; Journal Issue: 8; 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 SPECTROSCOPY; AEROSOLS; ANIONS; AQUEOUS SOLUTIONS; CHEMISTRY; DENSITY FUNCTIONAL METHOD; ELECTRONIC STRUCTURE; ENERGY LEVELS; EV RANGE; HYDRATION; NITRITES; NITROGEN; NITROGEN CYCLE; OXYGEN; SODIUM NITRATES; STABILIZATION; VISIBLE RADIATION; X-RAY SPECTROSCOPY