AMBER: vlimit exceeded, polarizable force field

From: Denis Courtier <>
Date: Thu, 29 Nov 2007 11:43:45 +0000

Hello everybody.

I am trying to run a polarizable force field, ff02pol.r1.

But, I got an error. Now, it is in md step. The error in my output file is:

vlimit exceeded for step 5; vmax = 36.3511
vlimit exceeded for step 6; vmax = **********

     Coordinate resetting (SHAKE) cannot be accomplished,
     deviation is too large
     NITER, NIT, LL, I and J are : 0 0 9 8 9

     Note: This is usually a symptom of some deeper
     problem with the energetics of the system.

My input files, for minimization and md, are:

Initial min-n
  imin=1, maxcyc=2500, ncyc=1000,
  cut=8.0, ntb=1,ntc=2,ntf=2

300K constant temp MD
  imin=0, ntb=1
  cut=8.0, ntc=2, ntf=2,
  tempi=300.0, temp0=300.0,
  ntt=3, gamma_ln=1.0,
  nstlim=520000, dt=0.002,
  ntpr=50, ntwx=50,

Can anybody help me? How can i control vlimit? Where is the origin of my
problem? Does i have to change the ensemble?

Thank you in advance.


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Received on Sun Dec 02 2007 - 06:07:18 PST
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