lammps/tools/moltemplate/common/graphene.lt

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# The minimal unit cell for graphine contains only 2 atoms:
# (which I arbitrarily named "C1" and "C2")
Graphene {
# atomID molID atomType charge x y z
write("Data Atoms") {
$atom:C1 $mol:... @atom:C 0.0 -0.61487803668695 -0.355 0.0000
$atom:C2 $mol:... @atom:C 0.0 0.61487803668695 0.355 0.0000
}
# Now define the "C" atom type
write_once("Data Masses") {
@atom:C 12.0
}
write_once("In Settings") {
# i j epsilon sigma
pair_coeff @atom:C @atom:C lj/cut/coul/long 0.068443 3.407
# These Lennard-Jones parameters come from
# R. Saito, R. Matsuo, T. Kimura, G. Dresselhaus, M.S. Dresselhaus,
# Chem Phys Lett, 348:187 (2001)
# Define a group consisting of only carbon atoms in graphene molecules
group Cgraphene type @atom:C
}
write_once("In Init") {
# -- Default styles (used in this file for graphene carbon) --
units real
atom_style full #(full enables you to to add other molecules later)
pair_style hybrid lj/cut/coul/long 10.0
}
} # Graphene
# This is a 2-dimensional hexagonal unit cell. The unit vectors are:
#
# (2.4595121467478, 0, 0)
# (1.2297560733739, 2.13, 0)
#
# You can create a sheet of single-layer graphene this way:
#
# small_crystal = new Graphene [3].move(2.45951214, 0, 0)
# [3].move(1.229756, 2.13, 0)
#
# For thicker sheets, follow the instructions in the "graphite.lt" file.
#
# Note: The length of each carbon-carbon bond is currently 1.42 Angstroms.
# To increase it to 1.422 Angstroms, uncomment the following line:
#
# Graphene.scale(1.0014084507042254) # 1.0014084507042254 = 1.422 / 1.42
#
# You will have to change the unit cell lattice vectors (see above) accordingly