lj Potential


While using lj potential in my structure I find the following line in the example.

pair_style lj/cut 2.5

pair_coeff * * 1 1

pair_coeff 1 1 1 1.1 2.8

Here is total 5 parameter first two is the atom type and last two is the energy and sigma value. I did not understand the importance of the middle one. I found no clear explanation anywhere. Can any body help.


it’s atomtype1 atomtype2 epsilon sigma cutoff
read the manual

And cutoff is optional, hence the line with 4 params.