Hello LAMMPS users,
I am trying to simulate polymer chains inside the sphere.
I wanted my sphere wall should be repulsive and chose the same value of sigma and cutoff. but when i am counting the atoms near the surface between 0.5 radial distance to previous layer it showed 1/3 of the whole atoms. This means wall is attractive and atoms want to stay at near to wall.
So, my question is how to get pure repulsive wall? How much value should i give for sigma and cutoff so that wall would be repulsive.
I am pasting my code here.
variable fname index data_box.dat
units real
boundary p p p
atom_style bond
read_data ${fname}
group big1 type 1
group big2 type 2
neighbor 0.4 bin
neigh_modify every 10 one 10000
bond_style harmonic
bond_coeff 1 350 1.53 ##id K r0
pair_style lj/cut 10.5
pair_coeff 1 1 0.112 4.01 10.5
pair_coeff 1 2 0.112 4.01 10.5
pair_coeff 2 2 0.112 4.01 10.5
region mySphere sphere 0.0 0.0 0.0 30.0 side in ##29.24
velocity big1 create 500.0 1231
velocity big2 create 100.0 2345
fix 1 big1 nve/limit 0.05
fix 2 big1 langevin 500.0 500.0 10.0 904297
fix wall1 big1 wall/region mySphere lj126 1.0 1.5 1.5 ##epsilon, sigma, cutoff
fix 3 big2 nve/limit 0.05
fix 4 big2 langevin 100.0 100.0 10.0 904297
fix wall2 big2 wall/region mySphere lj126 1.0 1.5 1.5
timestep 1 ##femotsecond
thermo_style custom step temp press fmax fnorm
thermo 100 ##print thermodynamics info at 100 timesteps
dump 1 all dcd 100 dump.dcd
run 10000
Thanks.
Regards
Ankit Agrawal
Student of Computational Biology
IMSc India