[gmx-users] calculating LJ

[Justin Lemkul]

On 3/27/13 2:15 AM, 라지브간디 wrote:
> Hello gmx,
>
>
> I have LJ parameter value of C (epsilon = 0.0262 kcal/mol,   sigma = 3.83) O (epsilon = 0.1591. sigma = 3.12) in charmm format and wants to use them in gromos43a1 or charmm27 force field in gromacs.
>
>
> Could you tell me how do i convert them to gromacs format? Any examples plz.
>
>

Equation 5.1 in the manual, or apply g_sigeps.  Note that picking values of 
atoms randomly and inserting them into an existing force field is a great way to 
completely invalidate the force field.  Atom types are balanced against one 
another.  Making ad hoc changes means you're using an unvalidated parameter set, 
and any good reviewer is going to have serious issues with whatever data you 
produce.

-Justin

-- 
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Justin A. Lemkul, Ph.D.
Research Scientist
Department of Biochemistry
Virginia Tech
Blacksburg, VA
jalemkul[at]vt.edu | (540) 231-9080
http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin

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