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Abstract: (Chemical Abstract 2000, 133:228181)
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The Atoms in Molecules Theory description for the X-O
(X=N,P) bonds in hypervalent molecules has been tested at
various levels and basis sets.
Calculations in H3PO, F3PO, H3NO,
F3NO molecules
have been carried out at the HF, B3LYP and MP2(full) levels
using the 3-21G, 3-21G*, 6-31G, 6-31G*, 6-311G, 6-311+G*
and 6-311+G(3d,2p) basis sets, showing that polarization
functions are essential for an adequate
geometrical description of hypervalent molecules,
especially when second row atoms are present.
The dependence of the numerical parameters at the
different bond critical points and the Bader charges
on X and O atoms have been studied by the aforementioned methods.
The AIM analysis is independent from the chosen level or basis sets,
when polarization function are present.
The geometry dependence of the X-O Bader analysis has also been
tested by performing calculations for H3PO by varying P-O bond
lengths.
This analysis has been proven as invariable for medium
bond lengths variations.
The results are also compared with the
H3P···O van der Waals complex.
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