Re: AMBER: NaCl ion pairs in TIP3P water box

From: David A. Case <>
Date: Wed, 24 Sep 2003 14:09:06 -0700

On Wed, Sep 24, 2003, Nathan A. Baker wrote:
> However, I invariably end up with ion pairs by the time I reach the
> 150-200 K stage of this procedure. The appearance of ion pairs does
> occurs with or without Step 4; I added that as an additional attempt
> to keep the ions apart.

Nathan: I hope Tom Cheatham or Tom Darden will speak up here, but I suspect
that this is a force-field "problem". Do the ion pairs break up if you
soldier ahead and go to 300K, or do they remain? I don't have any explicit
relevant experience, but I seem to have heard of similar problems through
the grapevine. (If you haven't done so, ask Jay what he thinks...)


David A. Case                     |  e-mail:
Dept. of Molecular Biology, TPC15 |  fax:          +1-858-784-8896
The Scripps Research Institute    |  phone:        +1-858-784-9768
10550 N. Torrey Pines Rd.         |  home page:                   
La Jolla CA 92037  USA            |
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Received on Wed Sep 24 2003 - 22:53:01 PDT
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