Read ReaxFF parameter file

[Fabian Ducry]

Dear all I would like to run simulations with the parameter from a certain publication (Atomic origin of ultrafast resistance switching in nanoscale electrometallization cells, doi:10.1038/nmat4221). I do have the set of parameters but loading the file with

Code

potentialSet = TremoloXPotentialSet(name='reaxff_test')
potentialSet.addParticleType(ParticleType(symbol='O',
                                          mass=15.9994*atomic_mass_unit))
potentialSet.addParticleType(ParticleType(symbol='Cu',
                                          mass=63.5*atomic_mass_unit))
potentialSet.addParticleType(ParticleType(symbol='Si',
                                          mass=28*atomic_mass_unit))
potentialSet.addPotential(ReaxFFPotential(file='ffield_CuSiO.txt',
                                          qeq=True,
                                          qeqEps=1.000000e-06,
                                          qeqMaxIter=200,
                                          lgvdw=False,
                                          bond_rcut=5.0*Angstrom,
                                          hbond_rcut=7.5*Angstrom,
                                          thb_bond_rcut=1e-8,
                                          thb_bond_rcutsq=1e-16,
                                          multiwell=False,
                                          strict_bondpairs=True))

fails: RuntimeError: Error in ...reaxff.c line 5402: ReaxFF data file ffield_CuSiO.txt not valid: could not read atom name and its Atomic number The parameters are in the attached file. How do I need to format the file to be read, is there an example somewhere? Thanks in advance Fabian Ducry

[Anders Blom]

I'm not an expert on the ReaxFF file format, but I took a look at some other parameter files we have, and I noticed the 2nd line is something like
6 C 6 H 1 O 8 N 7 S 16 Si 14
and this is missing in your file. So maybe if you add that (+ adding Cu 29, and maybe removing irrelevant entries; I guess the first "6" is the number of elements) things work better?
Not sure if this is standard in the ReaxFF format...

[Fabian Ducry]

This additional line did the trick. Everything works smoothly now, thank you!