Bead-spring model with different bead size.

I want help from some one. I am new to LAMMPS and I want to simulate a bead-spring polymer of A-B type(A & B are beads with different size) with force field- LJ+FENE. I have used ASPHERE package but I can’t use bonds with that.

I want help from some one. I am new to LAMMPS and I want to simulate a bead-spring polymer of A-B type(A & B are beads with different size) with force field- LJ+FENE. I have used ASPHERE package but I can't use bonds with that.

for LJ+FENE you don't need ASPHERE, but MOLECULE.

besides, you *can* combine atom styles via atom style hybrid, so
claiming that styles in ASPHERE do not work with bonds is incorrect.

axel.

... and you need to create a DATA file containing the list of bonds
between atoms (and angles and dihedrals, if applicable).

The format of a LAMMPS "DATA" file is explained here:
https://lammps.sandia.gov/doc/2001/data_format.html
and in more detail here:
https://lammps.sandia.gov/doc/read_data.html
https://lammps.sandia.gov/doc/atom_style.html
(I recommend either "atom_style full" (if the particles have charge),
or "atom_style molecular" (if not). Actually, I recommend atom_style
full regardless, since it is the default used by most other software
which can read and write LAMMPS files.)

There's a simple example of a coarse-grained data file for a polymer
located here:
https://icme.hpc.msstate.edu/mediawiki/index.php/LAMMPS_Polymer
(also see https://icme.hpc.msstate.edu/mediawiki/index.php/LAMMPS_tutorials)

You can create these files yourself, or you can use an external
software program to do it:
https://lammps.sandia.gov/prepost.html

In that case, for a coarse-grained model such as this, I suggest
either moltemplate or topotools. (Disclaimer: I wrote one of these
tools.)

Cheers

Andrew