Lost atoms

Dear all

Please tell me what’s wrong with this problem, it is giving lost atom 10976 current 7422,i have tried every thing like, thermo_modify lost ignore tried dt **small to large,changed velocity ,**but got same, lost atom T will be 750 only dont have to change this value.

Please put valuable suggestion,

Thanks in advance

Sample LAMMPS input script for viscosity of Glassy CuZr alloy

variable T equal 750
variable V equal vol
variable dt equal 0.01
variable p equal 2 # correlation length
variable s equal 50 # sample interval
variable d equal $p*$s # dump interval

convert from LAMMPS real units to SI

variable kB equal 1.3806504e-23 # [J/K/ Boltzmann
variable atm2Pa equal 101325.0
variable A2m equal 1.0e-10
variable ps2s equal 1.0e-12
variable convert equal {atm2Pa}*{atm2Pa}{ps2s}*{A2m}{A2m}*{A2m}

setup problem

units metal
echo both
atom_style atomic
dimension 3
boundary p p p
region box block 0 50 0 50 0 50 units box
create_box 2 box
lattice fcc 3.61 orient x 10 0 0 orient y 0 10 0 orient z 0 0 10
region cu block 0 50 0 50 0 50 units box
create_atoms 1 region cu units box
set region cu type/fraction 2 0.5 12393
pair_style eam/fs
pair_coeff * * …/…/…/…/…/potentials/CuZr_mm.eam.fs Cu Zr
run_style verlet
timestep ${dt}
thermo $d
thermo_style custom step temp pe etotal press vol

equilibration and thermalization

velocity all create $T 102486 mom yes rot yes dist gaussian
fix NVT all nvt temp $T $T 10 drag 0.2
run 8000

viscosity calculation, switch to NVE if desired

#unfix NVT
#fix NVE all nve
reset_timestep 0
variable pxy equal pxy
variable pxz equal pxz
variable pyz equal pyz
fix SS all ave/correlate $s $p $d &
v_pxy v_pxz v_pyz type auto file Cu5Zr5.dat ave running

variable scale equal {convert}/({kB}$T)$V*s*{dt}
variable v11 equal trap(f_SS[3]){scale} variable v22 equal trap(f_SS[4])*{scale}
variable v33 equal trap(f_SS[5])
${scale}

thermo_style custom step temp press v_pxy v_pxz v_pyz v_v11 v_v22 v_v33

run 100000
variable v equal (v_v11+v_v22+v_v33)/3.0
variable ndens equal count(all)/vol
print “average viscosity: $v [Pa.s/ @ T K, {ndens} /A^3”

Anik shrivastava
Senior Research Fellow
Naval Materials Research Lab,DRDO
Mumbai-400085
India

The usual comments apply. Check that your are being consistent with the units employed. Always make sure that your initial geometry is minimized (and converged). You probably have a bad structure to start with or your units and your potential don’t like each other, etc.
Carlos