Hello again LAMMPS users,

I am performing some tests over a bulk conformed by 64,000 atoms, I tried to incorporate a vacancy defect to see the resulting behavior, for this I read that the command delete atoms can delete a specific fraction of atoms randomly, it goes like

delete_atoms porosity region fraction seed

the problem is that by the time of using it the atoms are not erased or it erase a really low number of atoms, I have tried many combinations of “fractions” and “seeds”, even some that should generate an error by example set fraction to 10 (supposedly represents 1000%), at the end I have only managed to delete 16 atom (roughly a 0.0025%). Next is the starting piece of my scrip

# ----------- INITIALIZATION ------------

units metal

dimension 3

boundary p p p

atom_style atomic

atom_modify map array

# ------- INPUTS ---------

# modify this part for the bulk size

# a,b,c (x,y,z)=box size

variable a equal 40

variable b equal 20

variable c equal 20

# ---------- Create Atoms -----------

#Ni

lattice custom 1.0 a1 2.999 0 0 a2 0 2.999 0 a3 0.0 0.0 2.999 &

basis 0.0 0 0.0 orient x 1 0 1 orient y 0 1 0 orient z -1 0 1

region supercell prism 0 4.22 0.0 2.999 0.0 4.22 0 0 0 units box

create_box 2 supercell

create_atoms 1 region supercell

#Ti

lattice custom 1.0 a1 2.999 0 0 a2 0 2.999 0 a3 0.0 0.0 2.999 &

basis 0.5 0.5 0.5 orient x 1 0 1 orient y 0 1 0 orient z -1 0 1

create_atoms 2 region supercell

replicate $a $b $c

# ---------------- Defining porosity 1=100% -------------

delete_atoms porosity supercell 0.01 45348

# ----------- POTENTIAL --------------------

As always thank you for your help and any hint of why this happens is very welcome

Mario Muralles