Local vibrational dynamics of hematite (α-Fe₂O₃) studied by extended x-ray absorption fine structure and molecular dynamics

The local vibrational dynamics of hematite (α-Fe2O3) has been investigated by temperature-dependent extended x-ray absorption fine structure spectroscopy and molecular dynamics simulations. The local dynamics of both the short and long nearest-neighbor Fe-O distances has been singled out, i.e., thei...

Full description

Saved in:
Bibliographic Details
Published in:The Journal of chemical physics 2014-06, Vol.140 (22), p.224504-224504
Main Authors: Sanson, A, Mathon, O, Pascarelli, S
Format: Article
Language:English
Subjects:
ABSORPTION
ABSORPTION SPECTROSCOPY
ANISOTROPY
ATOMIC DISPLACEMENTS
Computer simulation
DISTANCE
Dynamic structural analysis
FERRITES
FINE STRUCTURE
HEMATITE
INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY
IRON OXIDES
Molecular dynamics
MOLECULAR DYNAMICS METHOD
Molecular structure
MORIN
Physics
SIMULATION
TEMPERATURE DEPENDENCE
THERMAL EXPANSION
X RADIATION
X ray absorption
X ray spectra
X-RAY SPECTROSCOPY
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The local vibrational dynamics of hematite (α-Fe2O3) has been investigated by temperature-dependent extended x-ray absorption fine structure spectroscopy and molecular dynamics simulations. The local dynamics of both the short and long nearest-neighbor Fe-O distances has been singled out, i.e., their local thermal expansion and the parallel and perpendicular mean-square relative atomic displacements have been determined, obtaining a partial agreement with molecular dynamics. No evidence of the Morin transition has been observed. More importantly, the strong anisotropy of relative thermal vibrations found for the short Fe-O distance has been related to its negative thermal expansion. The differences between the local dynamics of short and long Fe-O distances are discussed in terms of projection and correlation of atomic motion. As a result, we can conclude that the short Fe-O bond is stiffer to stretching and softer to bending than the long Fe-O bond.
ISSN:0021-9606
1089-7690
DOI:10.1063/1.4882282