bond_style fene/expand command
bond_style fene/expand/omp command
bond_style fene/expand bond_coeff 1 30.0 1.5 1.0 1.0 0.5
The fene/expand bond style uses the potential
to define a finite extensible nonlinear elastic (FENE) potential (Kremer), used for bead-spring polymer models. The first term is attractive, the 2nd Lennard-Jones term is repulsive.
The fene/expand bond style is similar to fene except that an extra shift factor of delta (positive or negative) is added to r to effectively change the bead size of the bonded atoms. The first term now extends to R0 + delta and the 2nd term is cutoff at 2^(1/6) sigma + delta.
Styles with a gpu, intel, kk, omp, or opt suffix are functionally the same as the corresponding style without the suffix. They have been optimized to run faster, depending on your available hardware, as discussed on the Speed packages doc page. The accelerated styles take the same arguments and should produce the same results, except for round-off and precision issues.
These accelerated styles are part of the GPU, USER-INTEL, KOKKOS, USER-OMP and OPT packages, respectively. They are only enabled if LAMMPS was built with those packages. See the Build package doc page for more info.
You can specify the accelerated styles explicitly in your input script by including their suffix, or you can use the -suffix command-line switch when you invoke LAMMPS, or you can use the suffix command in your input script.
See the Speed packages doc page for more instructions on how to use the accelerated styles effectively.