CCL:G: TS calculation with PCM

 Sent to CCL by: "Sten Nilsson Lill" [stenil|,|chem.gu.se]
 Dear Chunyi,
 by assuming you are using Gaussian you can add a sphere on a specific
 hydrogen by adding the keyword "SPHEREONH=N" in the route card of your
 pcm
 calculation. Here, N is the position of that hydrogen in your atom
 coordinate list. In the Gaussian manual you can read about this and also
 how to add keywords to the scrf calculation.
 Hope this helps!
 Regards,
 Sten Nilsson Lill
 >
 > Sent to CCL by: "Chunyi  Sung" [juneyi1[*]yahoo.com.tw]
 > Hi,
 >
 >    I am studying a gas phase reaction using PCM model
 > to see how the reaction goes in the presence of a solvent.
 > When I tried to find the transtion state structure with
 > PCM model (started with the transition state structure found
 > in gas phase), I got an error like this before getting any
 > SCF cycle done:
 >
 > United Atom Topological Model (UA0  parameters set).
 > UA0: Hydrogen 2 is unbound. Keep it explicit at all point on the
 > UA0: potential energy surface to get meaningful results.
 >
 > This step is actually about a hydrogen transferring from
 > a carbon to oxygen, so the hydrogen was not closely bound
 > to any atoms in the initial geometry (the transition state
 > structure in gas phase).
 >
 > So, what do I do to keep the hydrogen explicit?
 > or this error is just telling me that this reaction is actually
 > not going to happen in the solvent?
 >
 > thanks
 >
 > Chunyi>
 >
 >
 >
 Ph. D. Sten Nilsson Lill
 Dep. of Chemistry
 Göteborg University
 Kemigården 4
 S-412 96 Göteborg, Sweden
 Phone: +46-31-772 2901
 Fax: +46-31-772 3840
 E-mail: stenil|a|chem.gu.se
 Alternative e-mail: slill1|a|lsu.edu