I am trying to melt metallic nanoparticles on graphene and compare them with free (without graphene state).
The model is visualized here:
(the graphene is periodic and particles are about 5-7.7 nm)
I did this before (3 years ago) and results were reasonable.
But recently i tried to produce the same results and i cant, even with the same input.
I Plot the Potential Energy - Temp. for determining melting points and the results are nearly the same. and the curves are very similar: both Free Particle (Without Graphene) and Graphene Supported Supported
I uploaded the new curves here:
I test this for many inputs like different metals and even core-shells.
I think the problem is with my input
I attached it here:
and it is written bellow:
boundary p p f
mass 1 195.084
mass 2 12
pair_style hybrid eam airebo 3.0 lj/cut 6
pair_coeff 1 1 eam Pt_u3.eam
pair_coeff * * airebo CH.airebo NULL C
pair_coeff 1 2 lj/cut 0.1365 1.6 6
group graphene type 2
group particle type 1
velocity all create 298 8927079
neighbor 2 bin
neigh_modify every 20 delay 0 check no
compute 6 particle pe/atom
compute 7 particle reduce sum c_6
compute 8 particle temp
compute 10 all temp
compute 11 graphene temp
thermo_style custom step temp pe c_8 c_7 c_10 c_11
dump 1 all atom 250 dump-allheat1.atom
fix 1 all nvt temp 298 298 0.1
fix 2 particle nvt temp 298 2000 0.01
fix 3 particle nvt temp 2000 2000 0.1
for Free state it is simple and i plot the potential energy vs temp.
for the graphene supported state, I compute potential energy and temp of particle (compute 7 & 8) and plot them.
But i think i am making a mistake here.
because when i plot the total potential energy (including grahene atoms) vs temp i got the transition temp very different and i attached the picture here (it is the new blue curve):
Another Important Problem:
I used NVT for All particles just in relaxing in 298K temp.
During heating from 298, i can only heat the particle,
if i use NVT for all (in fix 2) the graphene will explode after some time and i will face LOST ATOMS error...
i really dont know how to heat particle and graphene together
could you please tell me what is the proper way to heat a particle on graphene??
and the correct way of computing potential energy and ploting PE-T curve?
(I tried different Cut offs different damping for NVT and everything... I know i am making a mistake in computing)
Sorry for taking your time and my awful English.
Thank you all