Hi,
I have a SiC surface and want to see the adsorption of Si atoms on my surface. for this reason I used hybrid/overlay to be able to use different potentials like this:
pair_style hybrid/overlay meam lj/cut 10.0
pair_coeff * * library.meam C Si SiC.meam C Si
pair_coeff 1 2 lj/cut 0.0 0.0
pair_coeff 2 2 lj/cut 0.0 0.0
but when I run my script, I get this error:
ERROR: Pair coeff for hybrid has invalid style: library.meam (…/pair_hybrid_overlay.cpp:63)
Last command: pair_coeff * * library.meam C Si SiC.meam C Si
Do you know the reason? and can you guide me?
maybe hybrid/overlay doesn’t work with meam?
Hi @Zahra_Rajabzadeh,
When using pair_style hybrid/overlay, the pair style to which the pair_coeff command applies must come right after the types in the pair_coeff invocation.
That is you must specify:
pair_coeff * * meam library.meam C Si SiC.meam C Si
You did it correctly with lj/cut below. The error message tells you that library.meam is not a valid pair_style.
Note that setting 0.0 0.0 coeffs for lj/cut will result in useless calculations that can be replaced by using pair_style zero.
No hybrid/overlay does work with meam. You just have to use it correctly.
Also, you need to factor in, that a) MEAM is a manybody model, you must not use it like it was pair-wise additive, there are some restrictions for using a manybody potential correctly with hybrid pair styles. there have been plenty of discussions about this in the past and there are explanations in the manual.
Furthermore, you need to be b) aware that hybrid/overlay is adding potential functions, so you have to be extremely careful in how you define your sub-styles to avoid double counting. While hybrid/overlay is less likely to throw errors compared to hybrid, it is more likely to execute a bogus models. The fact that LAMMPS does not complain does not indicate that a model is meaningful. LAMMPS only knows its implemented functionality and will execute it regardless of the physical meaning for as long as the syntax requirements are met.
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