# Tests Poisson solver, charge density restriction
# and electric field force prolongation
# Two groups of charged particles interact electrically
# using the long range electric field only, so they will 
# move towards each other
echo both
units 		metal
variable E equal 20.0
variable nx equal 16
# allow charges
atom_style full
dielectric      1.
dimension	3
boundary	p p p
lattice 	fcc   4.08 origin 0.25 0.25 0.25
region BOX block -8 8 0 3 0 3
create_box   3 BOX
create_atoms 1 region BOX
pair_style     lj/cut 10.
#pair_style	lj/cut/coul/long 10.
#kspace_style	pppm 1.e-4
#kspace_style	ewald 1.e-4
pair_coeff * * 0.2381 3.405
mass 		* 39.948
group  real region BOX
region LEFT block -5 -2 INF INF INF INF
region RIGHT block 2 5 INF INF INF INF
set             region LEFT type 2
set             region RIGHT type 3
set             region LEFT charge -1.
set             region RIGHT charge 1.
group		NION region LEFT
group		PION region RIGHT
neighbor        2. bin
###########################################################################
#fix EFIELD all efield $E 0.0 0.0
###########################################################################
fix         ATC real atc species_electrostatic Ar_species.mat
fix_modify  ATC add_species N group NION
fix_modify  ATC add_species P group PION
fix_modify  ATC  include atomic_charge
fix_modify  ATC  internal_quadrature off
fix_modify  ATC extrinsic short_range off
fix_modify  ATC mesh create ${nx} 1 1 BOX p p p
fix_modify  ATC atom_element_map eulerian 1
fix_modify  ATC  atom_weight multiscale
fix_modify  ATC  initial mass_density all 0.
#fix_modify  ATC  initial charge_density all 0.
fix_modify  ATC  initial electric_potential all 0. 
fix_modify  ATC mesh create_nodeset left_end -8.01 -7.99 -.1 .1 -.1 .1
fix_modify  ATC  fix electric_potential left_end 0.
#fix_modify  ATC mesh create_nodeset right_end 7.99 8.01 -.1 .1 -.1 .1
#fix_modify  ATC  fix electric_potential right_end 0.
# quick test for charged surfaces
#fix_modify  ATC mesh create_faceset left_end box -8 10 -10 10 -10 10 outward
#fix_modify  ATC extrinsic fix_charge left_end 0.
fix_modify  ATC  add_species NION type 2
fix_modify  ATC  add_species PION type 3
###########################################################################
variable n equal count(real)
print "number of atoms: $n"
timestep 	0.0005
thermo		100
compute   Fn NION reduce sum fx
compute   Fp PION reduce sum fx
thermo_style 	custom step etotal temp press pe c_Fn c_Fp
# initial thermo line should be:
#0    13699.992            0     12453927    13699.992    880.49388   -880.49388
fix_modify  ATC  output opp_forceFE 100 text binary
run 1000