[gmx-users] Lennard jones parameters for ions

[Justin Lemkul]

On 7/25/14, 8:21 AM, #SUKRITI GUPTA# wrote:
> Dear Justin,
>
> Thanks for your reply. Then it there any relation between charge density (for same element) and lj parameters e.g. for higher charge vander waals radius is smaller? Or are lj parameters randomly selected just to satisfy physical behavior of the ions?
>

There's nothing random about it.  You need some sort of target data - QM 
interaction energies, crystal geometries, hydration free energies, etc. to 
parametrize the model.  The parameters are tuned to agree with whatever data are 
deemed suitable.  Additive models of transition metals are generally very poor, 
though.  There are many effects that simply can't be captured by a point charge 
with a 12-6 LJ potential.

-Justin

-- 
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Justin A. Lemkul, Ph.D.
Ruth L. Kirschstein NRSA Postdoctoral Fellow

Department of Pharmaceutical Sciences
School of Pharmacy
Health Sciences Facility II, Room 601
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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