Dear lammps users,
I am working on a problem where the lattice parameter and cohesive energy of a crystal is to be found using relaxation method. This lattice parameter is then to be expressed as a function of temperature. Can someone tell me the script for doing so ?
The following is the script I have used:
---------- Initialize Simulation ---------------------
clear
units metal
dimension 3
boundary p p p
atom_style atomic
atom_modify map array
---------- Create Atoms ---------------------
lattice fcc 4
region box block 0 1 0 1 0 1 units lattice
create_box 1 box
lattice fcc 4 orient x 1 0 0 orient y 0 1 0 orient z 0 0 1
create_atoms 1 box
replicate 1 1 1
---------- Define Interatomic Potential ---------------------
pair_style eam/alloy
pair_coeff * * Al99.eam.alloy Al
neighbor 2.0 bin
neigh_modify delay 10 check yes
---------- Define Settings ---------------------
compute eng all pe/atom
compute eatoms all reduce sum c_eng
---------- Run Minimization ---------------------
reset_timestep 0
fix 1 all box/relax iso 0.0 vmax 0.001
thermo 10
thermo_style custom step pe lx ly lz press pxx pyy pzz c_eatoms
min_style cg
minimize 1e-25 1e-25 5000 10000
variable natoms equal “count(all)”
variable teng equal “c_eatoms”
variable length equal “lx”
variable ecoh equal “v_teng/v_natoms”
print “Total energy (eV) = {teng};"
print "Number of atoms = {natoms};”
print “Lattice constant (Angstoms) = {length};"
print "Cohesive energy (eV) = {ecoh};”
print “All done!”
Thanks and regards,
Hrushikesh Kulkarni,
Mtech student MEMS,
IIT BOMBAY,
Mumbai.