On Mon, Nov 21, 2011, Bruno Rodrigues wrote:
> The Temperature is quite high: 400K, and I'm using parmbsc0 on Amber11 for
> a 10bp short sequence.
> However my question is: what makes TIP4P and TIP5P less stable than TIP3P???
TIP4P/Ew boils somewhere near 380K; I'm not sure what happens to TIP3P at
those temperatures. Also, a 2fs time step becomes even less appropriate at
higher temperatures. Beyond that, as you say, it's a research problem.
You'd have to be sure everything is reproducible (TIP3P always "works", TIP4P
always "fails"); figure out what is really failing, etc.
> ...it nicely melted as expected.
Beyond everything else, are you sure you know what is "expected" at 400K?
You say you did "long NVE simulations after NpT equilibration", but are you
sure the NpT equilibration was not rather arbitrary? What density are you
dealing with? [You don't have to answer -- these are more on the line of
things to think about.]
...regards...dac
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Received on Tue Nov 22 2011 - 06:00:03 PST
