CCL: gaussian produces lots of imaginary frequencies



Dear Abhishek and Johannes
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.
Sincerely;
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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