Dear lammps users,

I am trying to simulate a 2layer material in which each layer includes Si and C atoms so, I have 4 types of atoms. Two types in the first layer and two types in the second layer.I use the following commands to introduce the tersoff potential between Si atoms(Si-Si) and C atoms (C-C). However I do not know how to introduce the tersoff potential between Si and C atoms.

pair_style hybrid tersoff lj/cut 12

read_data SiC2.dat

pair_coeff 1*2 3* lj/cut 0.004 3.212

pair_coeff * * tersoff 1 SiC.tersoff Si NULL NULL NULL

pair_coeff * * tersoff 2 SiC.tersoff NULL C NULL NULL

pair_coeff * * tersoff 3 SiC.tersoff NULL NULL Si NULL

pair_coeff * * tersoff 4 SiC.tersoff NULL NULL NULL C

Could anyone help me? Much appreciate it.

Best regards,

Nima Pirouzmand

Dear lammps users,

I am trying to simulate a 2layer material in which each layer includes Si

and C atoms so, I have 4 types of atoms. Two types in the first layer and

two types in the second layer.I use the following commands to introduce the

tersoff potential between Si atoms(Si-Si) and C atoms (C-C). However I do

not know how to introduce the tersoff potential between Si and C atoms.

pair_style hybrid tersoff lj/cut 12

read_data SiC2.dat

pair_coeff 1*2 3* lj/cut 0.004 3.212

pair_coeff * * tersoff 1 SiC.tersoff Si NULL NULL NULL

pair_coeff * * tersoff 2 SiC.tersoff NULL C NULL NULL

pair_coeff * * tersoff 3 SiC.tersoff NULL NULL Si NULL

pair_coeff * * tersoff 4 SiC.tersoff NULL NULL NULL C

Could anyone help me? Much appreciate it.

this input fragment is incorrect. your pair_coeff refers to 4

different tersoff styles in hybrid, but you only specify it once.

that said, if you have two "groups", why four pair_coeff sections and

what not simply two each containing both SI and C?

axel.

Dear Axel,

Thank you for your comment.

I thought that to add LJ interaction between Si,and C in two layers we need to have 4 type of atoms.

BR,

Nima Pirouzmand

Dear Axel,

Thank you for your comment.

I thought that to add LJ interaction between Si,and C in two layers we need

to have 4 type of atoms.

yes, but there is no contradiction. you can have two tersoff substyles

and 4 atom types.

axel.

OK. So, I put it this way,

pair_style hybrid tersoff tersoff lj/cut 12

read_data SiC2.dat

pair_coeff 1*2 3* lj/cut 0.004 3.212

pair_coeff * * tersoff 1 SiC.tersoff Si NULL

pair_coeff * * tersoff 2 SiC.tersoff NULL C

Correct? what about the interaction between Si and C?

BR,

Nima Pirouzmand

OK. So, I put it this way,

pair_style hybrid tersoff tersoff lj/cut 12

read_data SiC2.dat

pair_coeff 1*2 3* lj/cut 0.004 3.212

pair_coeff * * tersoff 1 SiC.tersoff Si NULL

pair_coeff * * tersoff 2 SiC.tersoff NULL C

Correct?

syntactically yes, logically no. you used to have 4 atom types. two

for each layer. what happened to those.

what about the interaction between Si and C?

i am extremely tempted to ask you to check the interaction between

your brain and your eyes. you seem to be reading what is suggested,

but not thinking about what you are doing, but rather try something

and hope that sooner or later you will hit a combination that will

work. that is not likely to happen. this is the last reply on this

thread from me.

what you need to do is straightforward to do and very logical, but you

will never learn how to solve problems logically, if i just tell you.

all you need to know is in the documentation existing examples and

what i've told you.

axel.