AMBER Archive (2003)

Subject: Re: a question about simulation at high temperature

From: Carlos Simmerling (carlos.simmerling_at_sunysb.edu)
Date: Thu Mar 20 2003 - 13:25:19 CST

Are you running at constant V or P?
If P, then the solvent should boil, correct?
Look at the density and see if this is the case.
If so, this _should_ happen at this T.
Try constant V. If there is still a problem,
it may be due to too large a timestep at
that T, you might need something smaller.
Carlos Simmerling

----- Original Message -----
From: "Xiaoqin Huang" <xiaoqin_at_csit.fsu.edu>
To: <amber_at_heimdal.compchem.ucsf.edu>
Sent: Thursday, March 20, 2003 8:38 AM
Subject: a question about simulation at high temperature

> Hi, Dear AMBER Users,
> Would you like to give some suggestions about the MD running at high
> temperature such as T=600K?
> When I set the temperature of simulation step by step (about 10 ps) from
100K
> to 300 K to 600K, it breaks down after about 15ps, it complains:
> "EWALD BOMB in subroutine ewald_list
> volume of ucell too big, too many subcells
> list grid memory needs to be reallocated, restart sander"
>
> what should I do to deal with this problem, is it just because the
properties
> of water molecules become abnormal? or the too low density of the system?
> thank you very much!
>
>
>
> --
> Dr. Xiaoqin Huang
> School of Computation Science and Information Technology
> Florida State University
> Tallahassee, FL32306
> U. S. A.
> Tel: 850-644-5792(O), 850-841-7716(H)
> Fax: 850-644-0098
> E-mail: xiaoqin_at_csit.fsu.edu, http://www.csit.fsu.edu
>
>