RE: Minimization/Equilibrium problem, atoms moving too fast

From: adrian palacios (adpala_at_hotmail.com)
Date: Thu Jul 18 2013 - 20:12:05 CDT

Yeah, but I tried to center my molecule's pdb before all preparations, so the actual system origin should be the same as the coordinates origin (0 0 0), but I will do it anyways, IŽll let you know what happens tomorrow.

Thanks for your help!

Adrian Palacios

Date: Thu, 18 Jul 2013 21:05:53 -0400
Subject: Re: namd-l: Minimization/Equilibrium problem, atoms moving too fast
From: broomsday_at_gmail.com
To: adpala_at_hotmail.com
CC: namd-l_at_ks.uiuc.edu

I'm not super familiar with exactly how NAMD does the periodic stuff or again what that VWD Boundary term means, but I wonder what would happen in your original larger simulation if you replaced:

"cellOrigin 0 0 0"

with

"cellOrigin 80.5 73.0 72.0"

Maybe nothing, but worth testing since it's a quick change.

On Thu, Jul 18, 2013 at 8:58 PM, adrian palacios <adpala_at_hotmail.com> wrote:

Before you answered I looked for the vdw "NAMD Plot" from the minimization log file and it does represent the greater contribution to this unstability, but how could I fix this? I tried running a similar system in a smaller box and it worked, but still is the second time I have this problem related to CaCl Ionization neutralizing the system.

Thanks for your reply, it was very accurate.

Adrian Palacios

Date: Thu, 18 Jul 2013 17:12:32 -0400
Subject: Re: namd-l: Minimization/Equilibrium problem, atoms moving too fast

To: adpala_at_hotmail.com
CC: namd-l_at_ks.uiuc.edu

>From the log, your energies actually go crazy low after minimization, not crazy high. And this seems to result from the ' VDW BOUNDARY' term. I'm not sure what this term applies to, but how confident are you in the cell dimensions you gave the system?

On Thu, Jul 18, 2013 at 4:28 PM, Adrian <adpala_at_hotmail.com> wrote:

-- 
Aron Broom M.Sc
PhD Student
Department of Chemistry
University of Waterloo
-- 
Aron Broom M.Sc
PhD Student
Department of Chemistry
University of Waterloo

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