Dear LAMMPS users
I am trying to simulate a box of H2 at room temperature. According to the literature that I found, the AIREBO potential should be used, however, it is used when there is graphene or similar and I do not understand how it should be used when only hydrogen is available. Is there any suggestion of a potential for lammps to realistically simulate a box of molecular hydrogen (H2)?
# ==================initial parameters ==========
variable dt equal 1
*variable Text equal 300.0 *
variable Pext equal 1.01325
units real
boundary p p p
atom_style full
bond_style harmonic
read_data data.hydrogen_H2
replicate 10 10 10
#=================Potential (Force Field) ===============
pair_style lj/cut/coul/long 9.0
pair_coeff 1 1 103.5 0.400 # H-H
kspace_style pppm 1e-6
neighbor 2.0 bin
neigh_modify delay 0 every 1 check yes one 11330 page 200000
timestep ${dt}
#============================= Thermo ===================
*thermo 10 *
thermo_style custom step temp press pe ke etotal ecoul epair lx ly lz vol
thermo_modify flush yes
#========== Minimization ===============================
*minimize 1.0e-4 1.0e-8 1000 10000 *
#=================== Equilibration ======================
*dump 1 all atom 10 H2.lammpstrj *
*fix 1 all npt temp {Text} {Text} (5.0*dt) iso {Pext} ${Pext} 10.0 *
run 4500
unfix 1
fix 2 all nvt temp 300 300 $(5.0dt)*
run 4500
unfix 2
fix 3 all nve
run 1000
write_restart restart.equil
I attach a script and the data.file.
data.hydrogen_H2 (447 Bytes)
in.H2 (1.3 KB)
Sincerely
Eduardo