[gmx-users] Error:EM did not converge while using polarizable ion

[折晓会]

Thank you professor Justin for the kind help!
I am wondering if you can provide me some links about hyperpolarization protection since I want to know where the parameters in "POL2" come from. Maybe I missed something, but I did not find corresponding parameters in the SWM4-NDP reference.
Best wishes,Xiaohui

> Date: Tue, 4 Aug 2015 19:23:42 -0400
> From: jalemkul at vt.edu
> To: gmx-users at gromacs.org
> Subject: Re: [gmx-users] Error:EM did not converge while using polarizable ion
> 
> 
> 
> On 8/4/15 5:40 PM, 折晓会 wrote:
> > Thank you professor Justin and Chaban for helpful suggestions!
> >
> > In the topology file, I choose "POL2" for water and anions, and the simulation seems working well now. The results of energy minimization are:
> >
> 
> Hyperpolarization protection is often needed in polarizable simulations, so the 
> use of "POL2" in the virtualchemistry.org files makes a big difference.  Without 
> this effect, polarization catastrophe is common.
> 
> > Steepest Descents converged to machine precision in 8755 steps,
> > but did not reach the requested Fmax < 1.
> > Potential Energy  = -3.0687320e+04
> > Maximum force     =  1.7012895e+02 on atom 2499
> > Norm of force     =  7.2500138e+00
> >
> > Are the results reasonable for the polarizable models? I am wondering why the final force does not match Fmax < 1.
> >
> 
> You'll never reach such a tolerance for the whole system using steepest descent 
> in singe precision.  That said, the outcome is perfectly reasonable.  The value 
> of emtol = 1 in the context of the Drudes/shells is that the maximum allowable 
> force on the Drudes themselves is set to 1 during the run for the purposes of 
> the SCF relaxation.
> 
> -Justin
> 
> -- 
> ==================================================
> 
> Justin A. Lemkul, Ph.D.
> Ruth L. Kirschstein NRSA Postdoctoral Fellow
> 
> Department of Pharmaceutical Sciences
> School of Pharmacy
> Health Sciences Facility II, Room 629
> University of Maryland, Baltimore
> 20 Penn St.
> Baltimore, MD 21201
> 
> jalemkul at outerbanks.umaryland.edu | (410) 706-7441
> http://mackerell.umaryland.edu/~jalemkul
> 
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