[gmx-users] Error on scaling the charges

[Justin Lemkul]

On 7/1/19 5:46 AM, Apramita Chand wrote:
> Dear Gromacs Users,
> I'm simulating an ionic liquid with AMBER 99sb-ildn ff in GROMACS 5.1.4
> package. With charges +1 and -1 on the cation and anion respectively, the
> system is neutral and the minimization is okay. But on scaling the charges
> by 0.8, the total charge shows to be above 6000, for a system of 2000
> particles each of cation and anion.
> Additionally, there are some errors that say :
> "atom O1 (Res MOL) has mass 0 (state A) / 0 (state B)"
>
> What could be the issue?

Sounds like your topology is totally broken in some way. Note that 
scaling charges such that you have a fractional total charge on any 
molecule is unphysical.

-Justin

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

Justin A. Lemkul, Ph.D.
Assistant Professor
Office: 301 Fralin Hall
Lab: 303 Engel Hall

Virginia Tech Department of Biochemistry
340 West Campus Dr.
Blacksburg, VA 24061

jalemkul at vt.edu | (540) 231-3129
http://www.thelemkullab.com

==================================================