ERROR: All pair coeffs are not set

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1

Hi Lammps Users,

I am trying to simulate a system with two layer on a substrate using hybrid function

pair_style hybrid/overlay lj/cut 20.0 tersoff airebo 3.0

pair_coeff * * tersoff SiC.tersoff Si NULL NULL
pair_coeff * * airebo CH.airebo NULL C NULL

giving error
ERROR: All pair coeffs are not set
means 3 or more types of atoms then SiC.tersoff and CH.airebo are not working but for 2 types of atoms they are working fine.

pair_style hybrid/overlay lj/cut 20.0 tersoff airebo 3.0

pair_coeff * * tersoff SiC.tersoff Si NULL
pair_coeff * * airebo CH.airebo NULL C

any help is greatly appreciated
regards

Sandeep Kumar Singh
PhD Student

2

Hi Lammps Users,

I am trying to simulate a system with two layer on a substrate using hybrid
function

pair_style hybrid/overlay lj/cut 20.0 tersoff airebo 3.0

pair_coeff * * tersoff SiC.tersoff Si NULL NULL
pair_coeff * * airebo CH.airebo NULL C NULL

giving error
ERROR: All pair coeffs are not set
means 3 or more types of atoms then SiC.tersoff and CH.airebo are not
working but for 2 types of atoms they are working fine.

well, where are the coefficient setting for the remaining
the first line uses tersoff for all type 1 atoms with type 1 atoms
the second line uses airebo for all type 2 atoms with type 2 atoms
but where are the coefficients for the combinations type 1 with type 2
type 1 with type 3, type 2 with type 3 and type 3 with type 3.
so - as LAMMPS tells you - not all pair coefficients have been set.

why does this surprise you?

axel.

3

Thanks Axel for your kind suggesion. Now problem is solved.

pair_style hybrid/overlay lj/cut 20.0 tersoff airebo 3.0
#pair_style tersoff
pair_coeff * * tersoff SiC.tersoff Si NULL NULL
pair_coeff * * airebo CH.airebo NULL C NULL

pair_coeff 1 3 lj/cut 0.01 3.4
pair_coeff 2 3 lj/cut 0.01 3.4
pair_coeff 1 2 lj/cut 0.01 3.4
pair_coeff 3 3 none