We report the nearest-neighbor oxygen-oxygen radial distribution function NN O–O RDF of room temperature liquid water and polycrystalline ice Ih −16.8 °C obtained by x-ray Raman based extended x-ray absorption fine structure EXAFS spectroscopy. The spectra of the two systems were taken under identical experimental conditions using the same procedures to obtain the NN O–O RDFs. This protocol ensured a measurement of the relative distance distribution with very small systematic errors. The NN O–O RDF of water is found to be more asymmetric tail extending to longer distances with longer average distance 2.81 Å for water and 2.76 Å for ice but a slightly shorter peak position 2.70 Å for water and 2.71 Å for ice. The refinement also showed a small but significant contribution from the linear O–H–O multiple scattering signal. The high sensitivity to short range distances of the EXAFS probe will set further restrictions to the range of possible models of liquid water.
Nearest neighbor oxygen distances in liquid water and ice observed by x-ray Raman based EXAFS
DI CICCO, Andrea;
2007-01-01
Abstract
We report the nearest-neighbor oxygen-oxygen radial distribution function NN O–O RDF of room temperature liquid water and polycrystalline ice Ih −16.8 °C obtained by x-ray Raman based extended x-ray absorption fine structure EXAFS spectroscopy. The spectra of the two systems were taken under identical experimental conditions using the same procedures to obtain the NN O–O RDFs. This protocol ensured a measurement of the relative distance distribution with very small systematic errors. The NN O–O RDF of water is found to be more asymmetric tail extending to longer distances with longer average distance 2.81 Å for water and 2.76 Å for ice but a slightly shorter peak position 2.70 Å for water and 2.71 Å for ice. The refinement also showed a small but significant contribution from the linear O–H–O multiple scattering signal. The high sensitivity to short range distances of the EXAFS probe will set further restrictions to the range of possible models of liquid water.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
