variable density equal 0.8
variable temperature equal 1.2
variable timestep equal 0.002

lattice sc ${density}
region box block 0 20 0 20 0 20
create_box 1 box
create_atoms 1 box

mass 1 1.0
pair_style lj/cut 3.2
pair_coeff 1 1 1.0 1.0
neighbor 2.0 bin

velocity all create ${temperature} 12345 dist gaussian rot yes mom yes
timestep ${timestep}

thermo_style custom step time etotal temp press
thermo 100

variable tdamp equal ${timestep}*100
fix nvt all nvt temp ${temperature} ${temperature} ${tdamp}
run 10000
reset_timestep 0

compute msd all msd
compute vacf all vacf
fix amsd all ave/time 1 1 1 c_msd[1] c_msd[2] c_msd[3] c_msd[4] file output-2
fix avacf all ave/time 1 1 1 c_vacf[1] c_vacf[2] c_vacf[3] c_vacf[4] file output-3

run 5000