Confusing part in the description of LAMMPS command

Hello everyone,
I am using LAMMPS with ReaxFF. I have a little confusion about the following which comes from manual of LAMMPS and describes pair_coeff:

As an example, say your LAMMPS simulation has 4 atom types and the elements are ordered as C, H, O, N in the ffield file. If you want the LAMMPS atom type 1 and 2 to be C, type 3 to be N, and type 4 to be H, you would use the following pair_coeff command:

pair_coeff * * ffield.reax C C N H

In the input data file, the atoms are in the sequence of C H N O, like this:

LAMMPS data file via write_data, version 1 Feb 2014, timestep = 50000

1792 atoms
4 atom types

0.0000000000000000e+00 2.6171570702085877e+01 xlo xhi
0.0000000000000000e+00 2.1937689376657051e+01 ylo yhi
0.0000000000000000e+00 2.8962100460609808e+01 zlo zhi

Masses

1 12.0107
2 1.00794
3 14.0067
4 15.9994.

So I use pair_style command like this:

pair_style	reax/c NULL lgvdw yes
pair_coeff	* * ffield.reax.lg C H N O

I wonder is the order of C H N O right? Should this sequence identical to the order in the input file?
Plus, I need to identify the reactive species. These is also an confusing order:
fix 3 all reax/c/species 1 10 100 species.out cutoff 1 4 0.3 cutoff 1 1 0.55

I wonder that in this set of cutoff distance, does 1, 2, 3, 4 means C H N O in the pair_coeff command or C H O N in the field file?

Thanks for your reply.
Guangyu Wang

2015/1/22 下午6:57 於 “WangGuangyu” <[email protected]…8…> 寫道:

Hello everyone,
I am using LAMMPS with ReaxFF. I have a little confusion about the following which comes from manual of LAMMPS and describes pair_coeff:

As an example, say your LAMMPS simulation has 4 atom types and the elements are ordered as C, H, O, N in the ffield file. If you want the LAMMPS atom type 1 and 2 to be C, type 3 to be N, and type 4 to be H, you would use the following pair_coeff command:

pair_coeff * * ffield.reax C C N H

Above is just an example and is not related to the data file below.

In the input data file, the atoms are in the sequence of C H N O, like this:

LAMMPS data file via write_data, version 1 Feb 2014, timestep = 50000

1792 atoms
4 atom types

0.0000000000000000e+00 2.6171570702085877e+01 xlo xhi
0.0000000000000000e+00 2.1937689376657051e+01 ylo yhi
0.0000000000000000e+00 2.8962100460609808e+01 zlo zhi

Masses

1 12.0107
2 1.00794
3 14.0067
4 15.9994.

So I use pair_style command like this:

pair_style reax/c NULL lgvdw yes
pair_coeff * * ffield.reax.lg C H N O

I wonder is the order of C H N O right? Should this sequence identical to the order in the input file?
Yes , they should be the same.

Plus, I need to identify the reactive species. These is also an confusing order:
fix 3 all reax/c/species 1 10 100 species.out cutoff 1 4 0.3 cutoff 1 1 0.55

I wonder that in this set of cutoff distance, does 1, 2, 3, 4 means C H N O in the pair_coeff command or C H O N in the field file?
In the pair_coefficient command.

Ray