About AIREBO and LJ potential

Hi,

My model has 3 atom types,

Interaction: 1-1 AIREBO, 2-2 AIREBO, 1-2 LJ, 1*3 - 3 NONE.

This is my input:

pair_style hybrid airebo 3.0 1 0 lj/cut 10.0
pair_coeff * * airebo CH.airebo C NULL NULL
pair_coeff * * airebo CH.airebo NULL C NULL
pair_coeff 1 2 lj/cut 1 1
pair_coeff 1*3 3 none

And this is an error:

ERROR: All pair coeffs are not set (…/pair.cpp:229)

Anyone has suggestion?

Hi,

My model has 3 atom types,

Interaction: 1-1 AIREBO, 2-2 AIREBO, 1-2 LJ, 1*3 - 3 NONE.

This is my input:

pair_style hybrid
airebo 3.0 1 0 lj/cut 10.0
pair_coeff * * airebo CH.airebo C NULL NULL
pair_coeff * * airebo CH.airebo NULL C NULL

The second line overrides the first so your 1-1 interactions are effectively nullified by “NULL”. You need only one line with “C C NULL” and the next line “1 2 lj/cut 11” defines the 1-2 interactions.

Ray

pair_coeff 1 2 lj/cut 1 1
pair_coeff 1*3 3 none

And this is an error:
ERROR: All pair coeffs are not set (../pair.cpp:229)

Anyone has suggestion?

If the input is:

pair_style hybrid airebo 3.0 1 0 lj/cut 10.0
pair_coeff * * airebo CH.airebo C C NULL
pair_coeff 1 2 lj/cut 1 1

pair_coeff 1*3 3 none

  1. It looks like interaction 1-2 are AIREBO at the second line and LJ at the third line.

  2. With or without the third line, the input could be done, so it does not make sense.

Please read the entire pair_style hybrid doc page: http://lammps.sandia.gov/doc/pair_hybrid.html, after which you will see the full sense of these 4 lines.

Ray