Dear all,
According to the empirical equation reported in the article about Development of a General Amber Force Field, J. Compu Chem. 2004, I am trying to parameterize the bond angle and the constant of the missing s6-c3-c3 (atom types) angle of Taurina. The MP2(6-31G*) results on the two models molecules are not very different from the GAFF angle and bond distances parameters but I am not able to obtain a sensible result for the bond angle force, also replacing the GAFF parameters:
GAFF parameters substituted:
Zs* Cc* Zc* r S-C r C-C theta**
c3-c-s6(rad)
1.28 1.339 1.183 1.76 1.53 1.9305965
*taken fron the article
**Theta= 0.5(tetha(c3-c3-c3)+tetha(s6-c3-s6)
Resulting angle force costant:
K(GAFF)=23.562 kcal/mol rad(-2)
I expected a constant K in the range of 50-70 kcal/mol rad(-2). I would like to know where is my fault.
Thanks!
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Received on Tue May 17 2005 - 17:53:01 PDT
