View
Publication Type
Journal Article
UWI Author(s)
Author, Analytic
Donald, Kelling J.; Mulder, Willem H.; von Szentpály, László V.
Author Affiliation, Ana.
Department of Chemistry
Article Title
Success and failure of polarized-ion models: Bending and atomization energy of groups 2 and 12 dihalides
Medium Designator
n/a
Connective Phrase
n/a
Journal Title
Journal of Chemical Physics
Translated Title
n/a
Reprint Status
n/a
Date of Publication
2003
Volume ID
119
Issue ID
11
Page(s)
5423-5436
Language
n/a
Connective Phrase
n/a
Location/URL
n/a
ISSN
n/a
Notes
n/a
Abstract
Polarized-ion models-with and without dipole reaction fields and charge-quadrupole interaction-are evaluated in calculating atomization energies, bond angles, and bending force constants of groups of 2 and 12 dihalides. A study of the sensitivity to changes in the input parameters reveals a strong dependence on dipole polarizabilities. The change-quadrupole bending terms of a multipole expansion are important for quasi-linear molecules, where the preceeding terms in the expansion tend to cancel each other. They normally stabilize the linear geometry, but enhance bent structures, if a certain criterion for the ratio of quadrupole polarizabilities of metal and halide ions is fulfilled. The models explain the bent alkaline earth halides, but fail spectacularly for the group 12 halides-HgBr The charge - quadrupole terms of a multipole expansion are important for quasi-linear molecules, where the preceeding terms in the expansion tend to cancel each other.They normally stabilize the linear geometry, but enhance bent structures, if a certain criterion is fulfilled. The models explain the bent akaline earth halides, but fail spectacularly for the group 12 halides - HgBr2 and HgI2 are even calculated as unstable relative to the constituent atoms. The unexpected weakness of ionic bonds is related to th elarge increase of the ionization energies by relativistic effects and the lanthanide contraction.....
read more
Keywords