reax/c hydrogen being picked up as oxygen


I am using reax/c, and I have 3 atom types. 1: C, 2:H, 3:H

I am using

pair_style reax/c NULL
pair_coeff * * field.reax.mattson C H H

When using

fix 3 all reax/c/species 10 10 100 species.out

The output of species.out indicates that the first hydrogen (2nd atom type) is be identified as O, oxygen.

Am I doing something wrong here? Can you not have 2 hydrogen atom types?

I do not have any oxygen in my system.




Please study the documentation for fix reax/c/species. Look for the “element” keyword and its default settings.

Please also remember to always report the version of LAMMPS you are using when reporting issues with LAMMPS commands.


See element keyword of the command.


Thank you Ray and Axel.