Generate Reaxff file NASH

LAMMPS LAMMPS General Discussion
1

Hello,

I am currently working on a NASH simulation. I am an engineering student at the University of Waikato and I am unable to find free software or information on the internet to build a Reaxff file for Na-Si-Al-O-H with the correct parameters.

To date, I have managed to perform several simulations that correspond to 70% of the publications, but none of them provide information on the structure of Reaxff files for geopolymers or how to adapt them.

I have relied on the only file available to me in the publication “Lyngdoh G.A., Kumar R., Krishnan N.M.A, Das S., (2019) ”Realistic atomic structure of fly ash-based geopolymer
gels: Insights from molecular dynamics simulations,“ Journal of Chemical Physics, Accepted, In press.” However, when analyzing the RDFs, inconsistencies in the graphs prevent me from validating the simulation.

The point on which I would like help concerns this reaxff file, which, in my humble opinion, is not consistent with the results of the publication, even though I have built the same simulation from scratch.

I look forward to hearing from you.

Adrien Cahoreau
Engineering apprentice
University of Waikato
Hamilton
New Zealand

2

Unfortunately you may well be correct in one of two ways: the authors may have mis-transcribed the ReaxFF files they used to generate their publication figures, or they may have performed insufficient sampling making their publication non-reproducible.

Sadly both are common features in contemporary molecular dynamics papers. Unless someone else happens to be an expert in this particular elemental mix, you might not get much useful information here on the LAMMPS forums. You may want to contact the authors of your mentioned paper directly – they will be more able to help you.

3

Thank you Sir for your answer.

4

The potential you are looking for was initially parameterized by Pitman and van Duin (2012) https://pubs.acs.org/doi/10.1021/ja208894m, you might be able to find what you are looking for there or at Yu et al. (2016) https://doi.org/10.1111/ijag.12248.