Dear all,

I am very grateful for the responses I have been receiving and really

appreciate this. I am new to LAMMPS and it has been very helpful. I am

still having problems running this system. The error this time is "Out

of range atoms--cannot compute PPPM".

1) Is it possible for FFTW to go wrong and cause this problem?

2) Is the problem solved by reducing the number of atoms in the

system? (There are currently 8336 atoms and 4624 bonds for the entire

system)

3) Is the problem solved by adjusting some of the commands in LAMMPS?

4) If it is an equilibration issue? How do I resolve this?

The input script is shown below:

# Nanofluid simulation input script

dimension 3

units metal

boundary p p p

neighbor 0.3 bin

neigh_modify delay 5

atom_style full

kspace_style pppm/tip4p 1.0e-4

read_data dataNULLcharge.nanofluid

#Pair_style hybrid definition

pair_style hybrid lj/cut/coul/long/tip4p 2 1 1 1 0.1250 2.5 eam lj/cut 2.5

#Definition of pair coefficients

#Water

pair_coeff 1*2 1*2 lj/cut/coul/long/tip4p 0.0 0.0 2.5 #pair

coefficients for tip4p between OH (LJ parameters set to zero)

pair_coeff 1 1 lj/cut/coul/long/tip4p 0.0 0.0 2.5 #pair

coefficients for tip4p between HH (LJ parameters set to zero)

pair_coeff 2 2 lj/cut/coul/long/tip4p 0.16275 3.16435 2.5 #pair

coefficients for tip4p between OO

bond_style harmonic

bond_coeff 1 450.000000 1.000000 #still not sure about these. How

did you work out that K is 450.000000!

angle_style harmonic

angle_coeff 1 55.000000 104.52 #still not sure about these. How did

you work out that K is 55.000000!

#Gold

pair_coeff 3 3 eam Au_u3.eam #pair coefficients for gold - where did

this come from???

#Water and gold together

pair_coeff 1*2 3 lj/cut 0.0 0.0 2.5 #pair coefficients for

interaction between water and gold is this correctly defined???

group hydrogen type 1

group oxygen type 2

group gold type 3

group all union hydrogen oxygen gold

fix 1 all nve

fix 2 all temp/rescale 100 0.45 0.45 0.02 1.0

fix 3 all enforce2d

thermo 50

run 1000

Once again thanks for your help.

Kind regards,

Folayo Osekita

MEng Student, Queen Mary, University of London