I disagree.
What one is generally trying to obtain with elevated temperatures is
enhanced sampling, not temperature-dependent properties. I believe
that even TIP4P-EW is not very good at getting the properties of water
correct at 600 K, temperatures that are commonly used during replica
exchange simulations (not to mention that nobody has any idea how
accurate protein forcefields are at temperatures other than the one at
which they were parameterized).
So I think that doing simulations at massively elevated temperatures
can possibly be useful.
That said, while doing simulated annealing, I have found previously
using charmm that once you get to about 3,000 K you will get chiral
inversions that can not resolve at lower temperature. This is because
our improper dihedral terms only maintain the given chirality, rather
than favouring one over the other.
To address your question directly, I believe that chiral inversions
will be a big problem for you at 20,000 K. Obviously you also have
simulation stability issues, but one presumes that you could resolve
those by using a small enough timestep.
Chris.
-- original message --
At that temperature most matter is going to be a plasma, not many
bonds to be simulated and a lot of free electrons.
Warren Gallin
On 2012-03-28, at 4:43 PM, Mark Abraham wrote:
[Hide Quoted Text]
On 29/03/2012 9:39 AM, Asaf Farhi wrote:
Dear GMCS users
Hi. Does anyone know if MD at 20000K is feasible?
Please start new email threads rather than hijacking old ones.
I doubt anybody knows the answer to your question. Force fields are
parameterized to reproduce data at around 300K. I can't imagine any
possible use for simulating an MM force field at a temperature hotter
than the sun.
Mark
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