AMBER Archive (2008)

Subject: AMBER: improper dihedrals in 03 united atom force field

From: Q733 (
Date: Tue Jul 22 2008 - 21:00:03 CDT

Dear amber-users:

      I have a question about improper dihedral parameters in ff03 united atom forcefield. As we all know, in order to prevent inversion of the stereochemistry,for united atom CH groups - sp3 carbons with one implicit hydrogen, improper dihedral parameters should be designed. However I can't see any improper dihedral parameters in the frcmod.ff03ua, how does ff03ua deal with CH improper dihedrals? If I want to simulate a branched alkane, can I use ff03ua forcefield?

This confused me a lot, will somebody please help me? Thanks very much in advance.


     Shanshan Qin

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