[lammps-users] References for RDX and TATB structures in the example files

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1

hi,

Are the references for the RDX and TATB structures used in the example files available? I would greatly appreciate it if someone can tell me how these data files were created; i mean, if some software was used or the numbers were obtained from a paper.

please let me know,
thanks in advance.

2

If you mean the atomic coords in examples/reax/data.rdx and tatb, then
these are just small toy problems for these molecules. Aidan can probably tell
you where he got the geometries for these problems.

Steve

3

Thanks for the reply Steve. Yes, i am referring to atomic coordinates in the data files for the reax examples. I am trying to build a bigger RDX crystal and was wondering if i can use those files as a starting point.

I will wait for Aidan’s reply.

4

These geometries were probably originaly obtained from x-ray
crystallography, followed by relaxation using the ReaxFF potential. I did
not create these myself, and so I do not have the journal citations.

One of the nice things about ReaxFF is that you do not need to specify a
list of covalent bonds, angles, or dihedrals, as these are computed on the
fly. Nonetheless, it can still be tricky to figure out a good initial
geometry for a brand new molecule. Open source tools that can help you do
this are: Avogadro and Towhee.

Aidan

5

IF you want to build a bigger crystal of RDX, you can certainly use the RDX
example. But you should also make sure you know which crystal polymorph you
want, as RDX exists in more than one form.

6

Thanks for the suggestions, Aidan.
Regarding the structure, i am trying to build an alpha-RDX.I will look into what you have said.