[lammps-users] Interaction within the molecule

Hi all,
How do we put interaction within a molecule.? Let 's say, one molecule consist of 4 particles of type 1 and 2 . And pair interaction or( pair coeff) within the molecule is different from interaction between particles in another molecule( it is also made of type 1 and 2). (eg 1 2 3 4 make one mole. 5 6 7 8 make another
mole. 1 and 5 are of same type (1) and rest is of type 2. the interaction between 1-2 ,1-3 , 1-4 are different from the interaction 1-6 ,1-7 or 1- 8) how do we that in lammps?

Thanks in advance.

Dear Prathyusha,

For all pairs you can use pair_coeff commands with appropriate potential.

pair_coeff 1 1 values

pair_coeff 2 2 values
pair_coeff 1 2 values

where values are non-bonded potential coeffcients.

Now, 1-2, 1-3, 1-4 inteactions (in your case) would not be evaluted as non-bonded interaction since they are connected within a molecule. They will be evaluated as bonded intections. If you had 5 atoms in each molecule, then 1-5 interaction will be similar to that of 6-10 and 1-10.

Regards,
Vikas.

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