[gmx-users] Lennard jones parameters for ions

[#SUKRITI GUPTA#]

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?

Regards
Sukriti


Sukriti Gupta (Ms) | PhD Student | Energy Research Institute @ NTU (ERI at N) | Nanyang Technological University
N1.3-B4-14, 50 Nanyang Avenue, Singapore 639798
Tel: (65) 81164191 GMT+8h | Email:sukriti002 at e.ntu.edu.sg | Web:erian.ntu.edu.sg



________________________________________
From: gromacs.org_gmx-users-bounces at maillist.sys.kth.se <gromacs.org_gmx-users-bounces at maillist.sys.kth.se> on behalf of Justin Lemkul <jalemkul at vt.edu>
Sent: Friday, July 25, 2014 7:46 PM
To: gmx-users at gromacs.org
Subject: Re: [gmx-users] Lennard jones parameters for ions

On 7/25/14, 7:39 AM, #SUKRITI GUPTA# wrote:
> Dear Gromacs users,
>
>
> I wanted to simulate metal ions in gromacs. For Fe+2, I have lj potential parameters already defined in OPLSAA forcefield, so I wanted to know if I want to add FE+3 in my simulation, then the LJ parameters for it will be different from that of Fe+2 or same?
>
>
> I thought it will be same because vander waals radii is defined for a element and not ion, hence it will be same for Fe or Fe+2 or Fe+3.
>

In any force field, LJ and electrostatic terms are parametrized to balance in
some way that produces some physically sensible behavior.  Given the extremely
high charge density of Fe2+ and Fe3+, I see no reason to think that the LJ
parameters for one would be the same as for the other.

-Justin

--
==================================================

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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