Re: [AMBER] problem in saving prmtop file in ff12SB force field

From: Daniel Roe <>
Date: Mon, 28 Oct 2013 08:04:09 -0600


On Mon, Oct 28, 2013 at 7:58 AM, Subrata Paul <> wrote:
> For atom: .R<Na+ 16>.A<Na+ 1> Could not find type: Na+

This issue has come up several times on the list (see e.g. etc). You need to load an
ion parameter set prior to adding ions. For example, to load the Joung
& Cheatham ion parameters for TIP3P:

loadamberparams frcmod.ionsjc_tip3p

See section 2.9 (Ions) of the AmberTools 13 manual for further details.

Hope this helps,


Daniel R. Roe, PhD
Department of Medicinal Chemistry
University of Utah
30 South 2000 East, Room 201
Salt Lake City, UT 84112-5820
(801) 587-9652
(801) 585-6208 (Fax)
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Received on Mon Oct 28 2013 - 07:30:03 PDT
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