Dear All,
I need to write a potential file for an alloy.
In the setfile fromat, the pair interactions should be in the order of (11) (21) (22)…
I read in the literature that (21) is the geometric mean of (11) and (22). I checked few alloy potetial files in the lammps potentials directory and found that (21) is not the geometric mean of (11) and (22).
Can anyone tell me how to calculate (21) interaction or suggest some sources where i can get the methodology.
Thanks
Sivashankar

Setting (21) to be the geometric mean of (11) and (22) is a rough approximation in the absence of better data. Better data typically comes from either fitting macroscopic properties to experimental measurements or quantum calculations. In many cases, other researchers have already done the hard work of force field fitting for you and all you need to do is find it in the literature.
Paul