[gmx-users] Zinc Oxide Simulation

[André Farias de Moura]

Hi Sapna,

just a few general comments:

(1) mixing parameters from different force fields is nearly always a bad
idea. In your case, it is probably worse, since Mulliken charges are not
actual force field charges.

(2) as a matter of fact, any charges from the reference you have pick up
should be seen with caution, since they report either DFT calculations or
ReaxFF simulations (which is not supported by GROMACS)

(3) any Zn2+ or O parameters from GROMOS or other force fields available
within GROMACS are not meant to treat ZnO or other similar material, they
usually apply to single zinc ions and small molecules containing oxygen.

(4) there are classical nonreactive force fields available, but you need to
check if they can reproduce the phases you're interested in. For instance:
http://pubs.acs.org/doi/full/10.1021/la9022739

best

Andre



On Thu, Apr 20, 2017 at 9:32 AM, SAPNA BORAH <sapnauser365 at gmail.com> wrote:

> Hi!
>
> We are working with ZnO nanoparticle structures generated from Virtual
> NanoLab Software, using the Wulff constructor.
>
> We are using gromos54a7ff for the simulation, and introduced ZnO parameters
> from literature.
> Partial charges for Zn= 1.026. For O= -1.026.
> (Surface Science 602 (2008) 1020–1031)
>
> Apart from this, the gromosff has default non bonded parameters for Zn2+
> and O.
>
> No information of ZnO bonded has been included, considering it to be ionic.
>
> The simulations have been run without any errors. However, we are doubtful
> about the charges and the usage of Zn2+.
>
> Any suggestion regarding this procedure would be appreciated. Thanks in
> advance.
>
> Sapna.
> Cheers.
>
>
> Sapna Mayuri Borah
> c/o Dr. A. N. Jha
> Research student
> Tezpur University,
> India
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-- 
_____________

Prof. Dr. André Farias de Moura
Department of Chemistry
Federal University of São Carlos
São Carlos - Brazil
phone: +55-16-3351-8090