[gmx-users] High temperature simulations

[Eric Jakobsson]

See-Wing Chiu in our group simulated the self-diffusion coefficient of 
SPC/E water up to 100 C and it tracked the experimental variation almost 
exactly, so I believe the variation with temperature in the liquid state is 
good.  (We never published that; it may be that somebody else has done it 
also.)

Eric

At 10:38 AM 3/4/2003 -0800, you wrote:
>Hi,
>
>No, all normal force fields are parameterised for liquid (that's the l in 
>OPLS) simulations at room temperature. I really don't know of any work 
>that has been done to systematically assess parameterisations at higher 
>temperature; it is difficult enough at normal temperatures :-)
>
>SPC/TIP3P are further very simple water models optimized for speed. The 
>freezing temperature is actually almost perfect, only a couple of degrees 
>off, but I can well imagine there are huge problems when you try to 
>vaporize it. Jay Ponder is doing work on very advanced water models 
>(including multipole interactions), but those are about two orders of 
>magnitude slower to simulate. There are a couple of slightly more advanced 
>models (compared to SPC/TIP3P) in the topology directory that you can play 
>with too.
>
>Cheers,
>
>Erik
>
>
>
>On Tuesday, Mar 4, 2003, at 03:20 US/Pacific, Oliver Beckstein wrote:
>
>>Hi,
>>
>>may I add my question to the one Dallas asked:
>>
>>Are these force fields (ffgmx, GROMOS, OPLSA,...) actually parametrised
>>for high temperatures (or more precisely: does one expect the
>>parametrisation to be T-independent (and if yes, over which range)), and
>>how much can you trust the simulated behaviour of proteins or water at
>>high T?
>>
>>(I know at least of two areas where this question may be important: One is
>>obviously the study of proteins at high temperatures, the other is use
>>of high T (>500K) simulations in replica exchange simulations to allow for
>>better sampling of configuration space)
>>
>>Oliver
>>
>>On Tue, 4 Mar 2003, Dallas Warren wrote:
>>
>>>This is just a general question about high temperature simulations.  I
>>>don't do them, and don't see that I will need to, but are simply curious 
>>>....
>>>
>>>Supposedly at 100oC, 373K, and 1 atm, water should boil.  Is it a
>>>deficiency in the force-field for H2O that it doesn't (i.e. it isn't a
>>>complete representation that exhibits this behaviour), or is something done
>>>to make it stay as a "liquid"?
>>
>>--
>>Oliver Beckstein * oliver at bioch.ox.ac.uk
>>  http://indigo1.biop.ox.ac.uk/oliver/
>>
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---------------------------------
Eric Jakobsson, Ph.D.
Professor, Department of Molecular and Integrative Physiology, and of 
Biochemistry
Senior Research Scientist, National Center for Supercomputing Applications
Professor, Beckman Institute for Advanced Science and Technology
4021 Beckman Institute, mc251
405 N. Mathews Avenue
University of Illinois, Urbana, IL 61801
ph. 217-244-2896       fax 217-244-2909