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INTERACTION MODEL. J. Bang. Acad. Sci., ALLOY. J. Bang. Acad. Sci., 2006, 30 (2), 177-
2007, 31 (1), 45-59. 187.

The A-B distances in regular, tetragonally distorted A detailed study of the crystallization behavior of
and trigonally distorted octahedral AB 6 molecules soft magnetic metallic glass Fe 73.5Au 1Nb 3Si 13.5B 9
are studied theoretically applying the Symmetry- has been carried out ty means of Differential
Interaction (SI) model where the different energies Scanning Calorimetry (DSC), X-ray diffraction
of orbitals in the valence level are assumed to (XRD) and theromagnetic measurements, Two
become closer by the interaction of those orbilals distinct crystallization peaks corresponding to
which have the common symmetry properties. The Fe(Si) and Fe-B phases were determined from
experimental bond lengths of about one hundred DSC traces and temperature dependence of
AB 6 molecules are collected from the literatures. In magnetization. The crystallization onset
all regular octahedral AB 6 molecules, formed by temperature and the nanometric grain size of
both the transition as well as the non-transition Fe(Si) phase has been determined from XRD
elements, the A-B distances are found to be exactly pattern of the samples annealed at different
equal and this equality is explained by proposed SI temperatures. Crystallization activation energies of
model. In case of transition metal complexes, sp-sp the Fe(Si) and Fe-B phases were found to be 2.36
and pd-pd interactions in the valence levels are and 4.26 eV. A satisfactory coincidence of the
found to be responsible for the orbital energy results of crystallization processes by DSC,
rearrangements in the inner-d and outer-d thermomagnetic measurements and XRD is
compounds respectively, in the complexes of non- obtained.
transition elements, the orbitals of the post valence
state, known as virtual orbitals, are assumed (with
some uncertainty) to take part in minimizing large 550 GEOLOGY
energy differences of the bonding orbitals.
Different configurations of tetragonally distorted 076 MAZUMDER, M.I.H.; HAQUE,
AB 6 molecules have different sets of bond M.N.& UDDIN, M.J. (Dept. of Electrionics &
distances and the reason for these variations was Applied Physics, Islamic University, Kushtia).
shown previously to be the Jahn-Teller effect GEOELECTRIC SURVEY IN DECIPHERING
which bases on the electronic interactions in the THE GROUND WATER ZONES IN THE
valence levels.The theoretical calculations on these TRIBENI UNION OF JHENAIDAH DISTRICT.
configurations by using the SI model are found to J. Bang. Acad. Sci., 2006, 30 (2), 213-223.
be unsuccessful in explaining the relative variation
of bond in most cases and hence the Jahn-Tellcr The results of geoelectric survey carried out in
theorem is considered as a better explanation. The Tribeni Union under Sailokupa Upazila of
trigonally distorted octahedral AB 6 molecules with Jhenaidah District have been discussed in this
antiprismatic geometry being structurally less article. Eight Schlumberger soundings were carried
stable, are too rare to record in the literature. But out in the middle of March, 2005. The data have
bond distances in a few prismatic complexes with been interpreted as a multilayer step function
bidentate ligands are available in literature and are resistivity model by an automatic iterative process
found to be equal. This equality is attributed to the proposed by Zohdy, 1989. An equivalent model of
energy averaging of the bonding orbitals by the d- minimum layers has been constructed for each
sd interactions. Thus the SI model is found to have location.The transverse and longitudinal resistivities as
nearly equal success and failure in explaining the well as co-efficients of anisotropy have been
bond distances in AB 6 molecules. studied. Groundwater table has been delineated
from the analysis of the co-efficients of anisotropy
075 SAHA, D.K. & HAKIM, M.A. of different formations and the measured values of
(Materials Science Division, Atomic Energy the groundwater conductivity. From a knowledge
Centre, Dhaka). CRYSTALLIZATION of geology, hydrogeology and co-efficients of
BEHAVIOR OF Fe 73.5Au 1Nb 3Si 13.5B 9 AMOR anisotropy, the results of the Vertical Electrical
PHOUS-NANOCRYSTALLINE SOFT MAGNETIC Soundings (VES) have also been used in

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