[lammps-users] On hybrid REAX FF

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1

Hello,

I am simulating a bilayer system with REAX FF comprising 2 surfaces. Surface #1 comprises C, H, O, and N; surface #2 is composed of C, H, O, and V. I have two REAX force field files for each surface. I am using hybrid pair_style to simulate the surfaces as follows;

S#1:

type1
type 2
type 3
type 4

S#2

type 5
type 6
type 7
type 8

pair_style hybrid reax/c NULL yes
pair_coeff * * reax/c ffield.reax.hns C H O N NULL NULL NULL NULL #Surface #1
pair_coeff * * reax/c ffield.reax.V_O_C_H NULL NULL NULL NULL C H O V #Surface #2

I am getting “ERROR: All pair coeffs are not set”. Could you please let me know what is wrong with the above setting?

I have been searching/reading the mailing list and LAMMPS archive for similar topics/issues, particularly over REAXFF implementation, but no success.

Any advice will be highly appreciated.

2

a) what you are doing is a very bad idea. ReaxFF is designed to be used with a single parameterization for all atoms
b) your input is not correct for the (bad) model you want to try. the second pair_coeff command will wipe out the assignments of the first.

3

Thank you very much Dr. Axel for your valuable time and feedback. I’ll try to modify my model accordingly.