High values of g(r) in rdf

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1

Hi,

Following input script I have used. Its quite simple, but the rdf values coming out are much higher than expected and I don’t think I have done any error in the script. i can’t seem to find the error. Please help

#… Initialization …
units metal
boundary p p p
atom_style atomic

#… Atom description …

lattice sc 3.47
region reg block 0.0 10 0.0 10 0.0 10
create_box 1 reg
create_atoms 1 box
mass 1 22.99 #Na

#… Dreiding potential information…
pair_style lj/cut 15.0
pair_coeff * * 0.0016 6.5
neighbor 1.0 bin
neigh_modify every 1 delay 5 check yes

group Na type 1

#… Equilibration…
velocity all create 373 1234567 dist gaussian
run 0
velocity all scale 373

timestep 0.001
thermo 1000

fix eq1 all nvt temp 473 473 100

dump 1 all xyz 10000 373equi_Na.xyz
run 450000

unfix eq1
undump 1

fix md all nve
compute rdf1 all rdf 100 1 1
fix rdfavg1 all ave/time 100 1 100000 c_rdf1 file rdf1.rdf mode vector
dump 1 all xyz 10000 373_Na.xyz
run 200000

Thanks.

2

Hi,

Following input script I have used. Its quite simple, but the rdf values
coming out are much higher than expected and I don't think I have done any
error in the script. i can't seem to find the error. Please help

well, the question is, are you simulating the system that you think you do?

1) you start with a simple cubic geometry, but sodium under normal
conditions is BCC, if i remember correctly.
2) are you sure that your potential parameters are correct. your sigma
of 6.5 is highly suspicious given the lattice parameters you use
3) point 2) is confirmed by the very high kinetic energy that quickly forms.
4) your Tdamp choice of 100ps for a timestep of 1fs doesn't make sense
either for an equilibration

...and this is just from having a quick look at your input.

axel.