lammps LJ input

#3d Lennard-Jones melt

variable x index 1

variable y index 1

variable z index 1

variable xx equal 10*$x # 10*10*10=1000 particles on a simple cubic lattice

variable yy equal 10*$y # 4*1000 = 4000 particles on a fcc lattice

variable zz equal 10*$z

variable dumpfreq equal 100 # dump snapshot frequency

variable thermofreq equal 100 # thermo output frequency

variable Tstart equal 2.0

variable Tend equal 2.0

variable Tdamp equal 0.1

variable rho equal 0.8 # number density N/V

variable dt equal 0.01

variable nsteps equal 10000

units lj

atom_style atomic

lattice fcc ${rho}

region box block 0 ${xx} 0 ${yy} 0 ${zz} # box range is from 0 to L

create_box 1 box

create_atoms 1 box

mass 1 1.0

velocity all create ${Tstart} 12345 loop geom

pair_style lj/cut 2.5

pair_coeff 1 1 1.0 1.0 2.5

neighbor 0.3 bin

neigh_modify delay 0 every 1 check yes page 100000

#neigh_modify delay 0 every 20 check no

fix 1 all nvt temp ${Tstart} ${Tend} ${Tdamp}

dump 1 all xyz ${dumpfreq} movie.xyz

dump_modify 1 element N

thermo ${thermofreq}

thermo_style custom step time temp ke etotal press vol spcpu cpuremain atoms

timestep ${dt}

run ${nsteps}