

AMBER Archive (2005)Subject: AMBER: GAFF angle parameters From: Monica Civera (monica.civera_at_unimi.it)Date: Tue May 17 2005  11:11:46 CDT
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 s6c3c3 (atom types) angle of Taurina. The MP2(631G*) 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:
*taken fron the article
**Theta= 0.5(tetha(c3c3c3)+tetha(s6c3s6)
Resulting angle force costant:
K(GAFF)=23.562 kcal/mol rad(2)
I expected a constant K in the range of 5070 kcal/mol rad(2). I would like to know where is my fault.
Thanks!

 
