Temperature equilibration

LAMMPS
1

Respected lammps users, I am using lammps version 15 Jun, 2023 MPI to wet Ag on the diamond substrate. Here when I applied the temperature fix and velocity seed with hybrid airebo for dimaond while eam for silver and lennard jones for interaction of both species the applied velocity seed temperature and temprature fix is 923 K but it bossts to 7000 K and disturbing NVT thermosetting if I use “”“pair_coeff * * airebo CH.airebo H NULL”“” for diamond but when I use pair coeff like “”“pair_coeff * * airebo CH.airebo C NULL”“” it controls the temperature within equilibration setting but this nullifies carbon forcefield and includes Hydrogen which I think is not suitable for case of diamond. The lammps scipts is here
“”"log log.mfacet

set potential function and parameters

units metal
dimension 3
boundary p p p
atom_style atomic

neighbor 0.5 bin
neigh_modify delay 5

region simbox block -75 117 45 299 -39 145 units box

lattice custom fcc 3.57

create_box 2 simbox
region diamondslab block -73 115 50 97 -39 145 side in units box

create_atoms 1 region diamondslab

lattice fcc 4.09

region silvercube block -16 59 100 155 30 80 side in units box

create_atoms 2 region silvercube

group slab region diamondslab
group silver region silvercube

group slab type 1
group silver type 2
mass 1 12
mass 2 107.8

pair_style hybrid airebo 3.0 eam lj/cut 12
pair_coeff * * airebo CH.airebo H NULL
pair_coeff 22 22 eam Ag_u3.eam
pair_coeff 1 2 lj/cut 0.043 3.5

thermo 1
thermo_style custom step lx ly lz press pxx pyy pzz pe temp
thermo_modify norm yes
thermo_modify lost ignore flush yes

#minimize 1.0e-21 1.0e-21 10000 10000
timestep 0.001

velocity silver create 923 12345 mom no rot no units box
run 0
velocity silver scale 923 units box

velocity slab create 923 12345 mom no rot no units box
run 0
velocity slab scale 923 units box

fix 1 silver nvt temp 923 923 0.1
fix 2 slab nvt temp 923 923 0.1
#fix 2 slab nvt temp 923 923 0.1
#fix 3 slab move linear 0 0 0
#fix 5 slab setforce 0 0 0
dump movie all atom 5 m.facet3
run 1100000"“”
I also tried with “”“velocity create all and fix all commands”“” but the results are similar only airebo potential interupts the temperature equilibration.
Kindly assist
Thanks for cooperation

2

You are not quoting correctly. You need to use triple backquotes ‘```’ for text blocks and single backquotes for inline quotes. You seem to be using triple double quotes ‘“”"’.

Diamond does NOT crystallize in an FCC crystal structure.

This is a very bad idea for almost any simulation except for when you want atoms to evaporate and leave the box. For almost everything else, it just masks problems with your simulation.

That is definitely incorrect since you are using hydrogen parameters to represent carbon.

You have to explain this statement. It makes no sense to me.

This statement also makes no sense and needs more explanation.