Dear lammps user and Merry Christmas
I have a problem with creating a binary mixture of fluid droplet. I have made a droplet by packmol to creat spherical form of the droplet. But when I apply fix nvt to the system the droplet collapses. All atoms are distributed to the vacant space in simulation box. I changed all the parameters which I think might be effective such as cut-off radius (20A), different initial atoms coordinates, long coulomb interaction(PPPM method) and truncated coulomb, increasing temperature NVT ensemble, the number of molecules from 2000 to 5000. I don’t know exactly what is the problem. In the following you can see my script as well:
units real
atom_style full
boundary p p p
special_bonds lj/coul 0.0 0.0 0.0
pair_style lj/cut/coul/long 15
bond_style harmonic
angle_style harmonic
kspace_style pppm 0.000001
read_data merging.data
pair_coeff 1 1 0.1553 3.166
pair_coeff 1 2 0.0 1.583
pair_coeff 1 3 0.16248 3.118
pair_coeff 1 4 0.0 1.583
pair_coeff 1 5 0.1793 3.4705
pair_coeff 2 2 0.0 0.0
pair_coeff 2 3 0.0 1.535
pair_coeff 2 4 0.0 0.0
pair_coeff 2 5 0.0 1.8875
pair_coeff 3 3 0.17 3.07
pair_coeff 3 4 0.0 1.535
pair_coeff 3 5 0.18759 3.4225
pair_coeff 4 4 0.0 0.0
pair_coeff 4 5 0.0 1.8875
pair_coeff 5 5 0.207 3.775
bond_coeff 1 1000 1.0
bond_coeff 2 386.0 1.425
bond_coeff 3 553.0 0.945
angle_coeff 1 100 109.47
angle_coeff 2 55.0 108.5
group spce type 1 2
group methanol type 3 4 5
group fluidbox union spce methanol
neighbor 3.0 bin
neigh_modify every 2 delay 0 every 1 check yes
fix fixnvtf all nvt temp 280 298.13 100.0
minimize 1.0e-4 1.0e-6 100000 400000
fix fixshake fluidbox shake 0.00001 20 10 b 1 2 3 a 1 2
timestep 1
restart 50000 R.restart
run 250000
thank you in advance for your time and your responses.
Sincerely,
Reza