Incorrect args for pair coefficients

LAMMPS LAMMPS General Discussion
1

I want to use the two potentials as below, but I get the following error

( The potential for 5 elements is available in the reaxff file and for the 6th type it is collected by the Buckingham potential.)

pair_style hybrid reax/c NULL buck/long/coul/long cut long 10.0
pair_coeff * * reax/c ffield.reax H O Si Al Li

pair_coeff 6 6 buck/long/coul/long 31120.528 0.154 5.
pair_coeff 6 5 buck/long/coul/long 33089.570 0.127 0
pair_coeff 6 2 buck/long/coul/long 16957.710 0.194 12.59
pair_coeff 6 3 buck/long/coul/long 8718.05 0.16 0
pair_coeff 6 1 buck/long/coul/long 6876.05 0.13 0
pair_coeff 6 4 buck/long/coul/long 5618.05 0.18 0

Data file:

13692 atoms
6 atom types

-45 45 xlo xhi
-45 45 ylo yhi
-20 20 zlo zhi

Masses

1 1.008
2 15.999
3 28.06
4 26.982
5 6.941
6 47.867

Atoms # charge

1 3 0 7.01012611 5.19957982 19.60705469 0 0 0
2 3 0 3.063745183 8.479191724 17.87568907 0 0 0
3 3 0 0.85227241 9.346146723 17.84144581 0 0 0
4 3 0 2.428806285 6.561066268 18.95117575 0 0 0
5 3 0 4.054471677 4.817618324 18.17818339 0 0 0
6 3 0 6.192635347 3.750588256 17.9054055 0 0 0
7 3 0 0.030899924 6.274040614 18.82376745 0 0 0

96

When I remove atom 6 from the structure and just use reaxff, there is no problem.
Could anyone guide me?

Thank you

2

This is documented behavior. The number of elements following the potential file name must be the same as the number of atom types. Please see the documentation of pair style reaxff and pair style hybrid.

3

Yes. The reaxff potential that I use contains only 5 elements and I made the database so that the order of these 5 types corresponds to the potential.
ffield.reax (10.0 KB)
Regardless of the hybrid style and the 6th atom, there is no problem, but I don’t understand the error and I don’t know what to change

4

Hello,
When using a 6th atom, you should write:

pair_coeff * * reax/c ffield.reax H O Si Al Li NULL

Where “the NULL values are placeholders for atom types that will be used with other potentials”.

Best,
Simon

5

I apologize for taking up your time

I was doing this at first, but I was getting the following error
2

6

As you should: Null != NULL

7

Wow, I’m so sorry. Thank you very much