NACL/WATER potential

Deal Lammps users,
I have a question and I appriciate any help and commants.
When I am running a simulatiuon of water/Nace with the potential as follow, the Na-Cl distance varies between 0.5 -1 nm, while it should be around 0.4-0.5.

TIP4P/Ew and NaCl Potential Parameters

pair_style hybrid lj/cut/coul/long 5.0 buck/coul/long 5.0 # This cutoff is too short for a real calculation

Load configuration

read_data data.nacl

create groups

group hy type 1
group ox type 2
group na type 3
group cl type 4

set charges - beside manually

set group ox charge -0.830
set group hy charge 0.415
set group na charge 1.0
set group cl charge -1.0

Water TIP3P

pair_coeff 1 1 lj/cut/coul/long 0.0 0.0
pair_coeff 2 2 lj/cut/coul/long 0.102 3.188
pair_coeff 1 2 lj/cut/coul/long 0.0 0.0

Mixed from Pettitt 86

pair_coeff 2 3 lj/cut/coul/long 0.1338549 2.72
pair_coeff 1 3 lj/cut/coul/long 0.1338549 1.31
pair_coeff 2 4 lj/cut/coul/long 0.359825 3.55
pair_coeff 1 4 lj/cut/coul/long 0.359825 2.14

NaCl from Pettitt 86

pair_coeff 3 4 buck/coul/long 28929.93 0.317 161.2016
pair_coeff 3 3 buck/coul/long 9772.847 0.317 24.18024 # This is not used
pair_coeff 4 4 buck/coul/long 80312.94 0.317 1683.981 # This is not used
bond_style harmonic
bond_coeff 1 450 0.9572
angle_style harmonic
angle_coeff 1 55 104.52
kspace_style pppm 1e-2 # This value is too large for a real calculation

simulation box is atached

data.nacl (21.9 KB)

Deal Lammps users,
I have a question and I appriciate any help and commants.
When I am running a simulatiuon of water/Nace with the potential as
follow, the Na-Cl distance varies between 0.5 -1 nm, while it should be
around 0.4-0.5.

?
Why do expect the Na and Cl ions to remain close to each other?
(spce example <http://moltemplate.org/visual_examples.html#waterSPCE+Na+Cl>)

### TIP4P/Ew and NaCl Potential Parameters ###