On Wed, Aug 29, 2012 at 2:42 AM, Adedapo
Adeyinka u11335132:-:
tuks.co.za <owner-chemistry*ccl.net> wrote:
Dear Gopakumar,
Like Cina said it would be impossible to reproduce the geometry of a molecule in
the solid phase with gas phase computations. However from my experience
calculations on molecules in solvent might be able to predict the geometry in
solid phase. So you can try to do computations on your molecule using DFT
with the PCM solvation model and the UFF force field.
Adeyinka Adedapo
Department of Chemistry,
University of Pretoria, South Africa
On 28 August 2012 16:06, G. Gopakumar
gopakumar.gopinadhan]^[
gmail.com <owner-chemistry-.-ccl.net> wrote:
Dear CCL
members,
I was calculating a molecule (71 atoms)
for which the crystal structure is
known. However, according to my
calculation, one of the dihedral angles shows
large mismatch (deviation of 12 degrees). I repeated the calculation with
both
B3LYP and BP86 functional and the values are given
below:
B3LYP/def2-TZVP ~ 21.2
BP86/def2-TZVP ~
20
Experimental ~
8.1
I would not worry too much if it was 2-3 degree deviation, but 12 is
something
that I should be careful with.
I was wondering, whether
there is a chance for an experimental error? Or is it
just that DFT
overestimates the dihedral angle? Does any body know any references
where people encountered similar problem.
I would be thankful for your
comments
with kind regards
Gopakumar
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