Re: [AMBER] rism1d convergence query

From: Tyler Luchko (Lists) <"Tyler>
Date: Wed, 27 Jun 2018 10:00:19 -0700

Hi Rakesh,

It sounds like you are trying to use a primitive model of an electrolyte solution. This can be done with rism1d but you will need make some adjustments. The dielectric constant you have set applies only if you have a polar molecule, like water, in the solution. For the primitive model, you should use theory=‘xrism’ and divide the charges of your ions by sqrt(78.5) in the MDL file.

If you are still having problems with convergence, please look at the ‘Solution Convergence’ section of the manual on page 106.

Hope this helps,


> On Jun 26, 2018, at 11:14 PM, Rakesh Srivastava <> wrote:
> Hello all,
> I want to perform rism1d calculation for a very asymmetrical ionic system.
> I have prepared mdl parameters files for two asymmetric ions but the
> numerical procedure for rism1d does not converge rather the resid parameter
> in out file shows oscillatory behavior (I am using KH closure and
> dielectric constant 78.5 but only two species in the system, no explicit
> water).
> My question is, whether there is a way to provide an initial guess for
> numerical solver from some previously converged less asymmetric system so
> that the chances of convergence could be increased?
> Any help will really mean a lot.
> Thanks.
> Rakesh Srivastava
> Research Fellow
> School of Computational & Integrative Sciences
> Jawaharlal Nehru University, New Delhi-110067
> India
> _______________________________________________
> AMBER mailing list

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Received on Wed Jun 27 2018 - 10:30:02 PDT
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