# two LJ particles

units real
boundary p p p

atom_style charge
pair_style lj/cut/coul/long/soft 1.0 0.0 0.0 12.0 12.0

region box block -15.0 15.0 -15.0 15.0 -15.0 15.0 
create_box 2 box

# just two atoms...
#create_atoms 1 single  0.0 0.0 0.0
## create_atoms 2 single  3.36738 0.0 0.0
#create_atoms 2 single  6.0 0.0 0.0

# ...or a few on a lattice
lattice bcc 5.0 
create_atoms 1 box basis 1 1 basis 2 2


mass   1  12.011
mass   2  12.011

pair_coeff   1   1   0.1   3.0  1.0
pair_coeff   1   2   0.1   3.0  1.0
pair_coeff   2   2   0.1   3.0  1.0

set type 1 charge  0.1
set type 2 charge -0.1

kspace_style pppm 1.0e-5

timestep 2.0

velocity all create 300.0 12345

fix INTEG all nvt temp 300.0 300.0 $(100.0*dt)

variable lam equal ramp(1.0,0.0)
variable q1 equal  0.1*v_lam
variable q2 equal -0.1*v_lam

fix ADAPT all adapt/fep 200 &
  pair lj/cut/coul/long/soft lambda * * v_lam &
  atom charge 1 v_q1 atom charge 2 v_q2

thermo_style custom step etotal ke pe epair evdwl ecoul elong temp press v_lam v_q1 v_q2
thermo 200

#dump TRAJ all custom 20 dump.lammpstrj id type element xu yu zu
#dump_modify TRAJ element C N

run 2000

#write_data data.*.lmp