| Fe3
+ Co-ordination Site in a-Fe20 3 -
An Evaluation of its Electronic Structure |
TAPAN PAL, TARAKNATIIPAL, S. ANNADURAI AND SAOIINATH MITRA
Pages : 126-129
DOI : 10.1080/0371750X.1992.10804559 |
| Abstract |
| The electronic structures of Fe3• co-ordination in iron oxide/
hydroxide phases are evaluated from Self Consistent Field Xa
Scattered ·Wave (SCF ·X a -SW) molecular orbital calculations on
the octahedral (Fe06)t-clusters and/or trigonally distorted (Fe06)9-
clusters. The electronic structures can be studied directly from
the diffuse refiectance, specular refiectance and optical absorption
methods. In a-Fe20 3 (haematlte) pairs of face sharing polyhedra
of (Fe06)t- share the edges and corners with each other to
form sheets of (Fe06)9- polyhedra perpendicular to c-axis. This
causes a strong trigonal distortion of (Fe06)9- polyhedra and
results in two triatomic clusters of 02- ions around a central Fe3•
ion. In haematite, most of the electronic transitions are caused by
ligand field transition and are Intensified by the pair excitation
(double exciton). |
| Full text : Subscribe to Download Full Text |
| [Go Back] |
|
