Re: AMBER: igb10 vlimit exceeded

From: Ray Luo <>
Date: Thu, 31 Mar 2005 08:52:50 -0800

Wells, David H wrote:

> Web Bug from MailScannerWebBug
> I’m trying to simulate a small organic solute in DMSO (83 molecules)
> with igb=10. Previously there was trouble with solvent “penetrating”
> the solute, apparently due to the way the non-bonded list is generated
> in igb=10. That can be gotten around, but now simulations more than 20
> ps are blowing up. The RESTRAINT energy ramps rapidly, vlimits start
> to be breached, and eventually temperature rises rapidly and solvent
> molecules are forcibly ejected from the “cap” (even with FCAP=1000.0).
> Changing igb=10 to igb=0 eliminates the problem.
> Are the FCAP restraints only applied on atoms with indexes > NATCAP ?
> Any further insights would be appreciated.
> Many thanks, Dave

We have never tested igb=10 with organic solvents, so whatever you see
is all very new to us. I'll be happy to debug it for your simulations.


Ray Luo, Ph.D.
Department of Molecular Biology and Biochemistry
University of California, Irvine, CA 92697-3900
Office: (949)824-9528         Lab: (949)824-9562
Fax: (949)824-8551          e-mail:
Home page:
The AMBER Mail Reflector
To post, send mail to
To unsubscribe, send "unsubscribe amber" to
Received on Thu Mar 31 2005 - 18:53:01 PST
Custom Search