Question about pair_coeff

Dear lammps users and developers,

I am simulating the liquid-solid interactions. Data file contents the pair_coeff in Pair Coeffs section. After reading the data file, a mixing rule is used to define all cross interactions. As the interactions of atoms of solid have different interaction parameters between them and with the atoms of liquid, these are modified using pair_coeff comand (after read the data file and defining all cross interactions).

My question is: This setup modifies only the pair coeffecient interactions using in pair_coeff comando for all simulation, or the pair coefficients are upload modifying all pair coefficients.

For example, for atoms of solid phase, the pair coefficient in data file correspond to the parameters of solid-liquid interactions. While in the input data, these parameters are modified for interaction between the atoms of solid phase using pair_coeff comand. The interactions between the liquid and solid are computed using the parameters of data file or are modified by the pair_coeff in the input data?

Thank for your valuable help.

Regards

Dear lammps users and developers,

I am simulating the liquid-solid interactions. Data file contents the pair_coeff in Pair Coeffs section. After reading the data file, a mixing rule is used to define all cross interactions. As the interactions of atoms of solid have different interaction parameters between them and with the atoms of liquid, these are modified using pair_coeff comand (after read the data file and defining all cross interactions).

My question is: This setup modifies only the pair coeffecient interactions using in pair_coeff comando for all simulation, or the pair coefficients are upload modifying all pair coefficients.

For example, for atoms of solid phase, the pair coefficient in data file correspond to the parameters of solid-liquid interactions. While in the input data, these parameters are modified for interaction between the atoms of solid phase using pair_coeff comand. The interactions between the liquid and solid are computed using the parameters of data file or are modified by the pair_coeff in the input data?

Thank for your valuable help.

Regards

I’m not clear what you are asking. But this may answer your Q.
LAMMPS applies a mixing rule at the point you invoke
the run or minimize command to perform a simulation.
At that point it will use all the inputs you have specified
up until then. E.g. pair coeffs read from the data file,
or ones you put in your input script. If you defined
a particular cross interaction explicitly (e.g. type 1 vs type 3),
then LAMMPS will do no mixing for that term. If you
didn’t define one, it will do mixing. If the combination
of the data file and pair_coeff commands in your input
script defined the same interaction more than once,
the last one will override all the previous ones.

Steve

Thanks Steve for your kind answer,

It was very useful for me. As Axel suggest me, I am simulating in a small system - setting up minimal test systems with just a few atoms, computing forces and energies manually and comparing for different combination of the data file and pair_coeff commands in my input script.