united-atom force-fields are quite common
If you use united-atom be careful with improper torsions, because
I was unable to get leap's method of applying them to work with
the canonical united-atom ff. This is because the old prep way
allowed you to specify the order of the three atoms; with leap
the order is arbitrary (based on atom name or type, I forget which),
and this doesn't work when the improper is not planar.
Bill Ross
Received on Tue Mar 06 2001 - 11:06:44 PST
