About potential sw for 2 atom types: Si Si

Hi LAMMPS users,

Model has 2 atom types: Si Si

Interaction between 1-1:Si.sw, 2-2: none and 1-2:Si.sw.

Anyone has suggestion how to define “pair_style” and “pair_coeff”?

you can use the hybrid pair style and specify sw twice. details in the
pair style hybrid docs. axel.

correction. i misread your description. 2-2 none and 1-1 plus 1-2
using sw is not possible. what i described would only work for 1-1 sw
and 2-2 sw and 1-2 none.
your desired kind of partitioning is only cleanly doable with pairwise
additive interactions.

please note that pair style sw with two Si type atoms not only
computes 1-1, 1-2, and 2-2 pairs but also computes 1-1-1, 1-1-2,
1-2-1, 1-2-2, 2-1-1, 2-1-2, 2-2-1, and 2-2-2 interactions (that is
what makes it a manybode potential).


If you really want to do this, you will have to edit the potential parameter file Si.sw.

You will have to expand the one-entry parameter file to 8 entries containing Si1 and Si2, similar to the CdTe.sw file format. Then in your Si1-Si2 parameter file, just set the A and B of Si2-Si2 interactions to zero.

You will use Si1 and Si2 as your elements in the pair_coeff command.