problem in TS searching
Hello everyone:
I met a strange thing in transition state searching in MOPAC. There
are three reactants, HOCH2CH2NH2, H2O and HCONH2 to complete the
reaction like the following:
NH2
|
HOCH2CH2NH2+H2O+HCONH2--->(+)NH3CH2CH2O(-)+ H2O +HCONH2 --->
(+)NH3CH2CH2O-C-O(-) +H2O
|
H
I use pseudo reaction coordinate technique to find the transtion state
of the first reaction, but when I use PM3 MMOK TS PRECISE to refine it,
I failed. Then I cut off the HCONH2 from the system, I can refine the
first TS I got, because I got one negative frequency.
Does anyone have some experients about the problem I met, hope you
can give me some suggestion. Thank in advance.
Regards,
mao
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| Mao Xiang |
| Lab of Molecular Regulation for Microbial Secondary Metabolism |
| Shanghai institute of Plant Physiology, Academia Sinica |
| 300 Fenglin Road, Shanghai, China, 200032 |
| Tel: +86-21-64042090-4791 |
| Fax: +86-21-64042385 |
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