I am afraid, you have done frequency calculations
at level different from the level you have optimized your molecule at. In other
words, frequency calculations must be done at the same level of
optimization, otherwise it will be meaningless.
If it is not the case, we would love to have a look on your
molecule.
M. Ibrahim
On Tue, Aug 31, 2010 at 5:26 AM, ABHISHEK SHAHI
shahi.abhishek1984(~)
gmail.com <owner-chemistry%%ccl.net> wrote:
Dear All
I have
similar problem as 'Johannes
Salewski ' . I am getting 3 or 4 or 5 or 6 or sometime 8
negative frequency for water complexes having 6 atoms only.Some negative
Frequencies are quite larger(`2300 cm-1).How to resolve this problem ? I have
tried it for 7-8 times but got nearly same result. I have chosen
#mp2=full/aug-cc-pvtz opt=(maxcycle=100) freq=noraman nosymm
scf=(tight,vshift=150,xqc) route section with enough memory.In output , Its
showing normal termination for both optimization and frequency calculation with
several order saddle point (i.e. more negative frequencies).I am looking for a
proper suggestion.
your suggestions will appreciated
With regards;
ABHISHEK
SHAHI
IISc bangalore-12
India
Official E-mail: shahi|*|ipc.iisc.ernet.in
CC: shahi.abhishek1984|*|gmail.com
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