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[lammps-users] How to calculate cohesive energy of an alloy

# [lammps-users] How to calculate cohesive energy of an alloy

 From: Vijay Reddy Date: Mon, 21 Aug 2017 00:14:46 +0530

Dear all,

I want to calculate the cohesive energy of Ni-Zr (4 at. %) alloy using lammps. But the tutorial provides calculation of cohesive energy for a single system.

I have modified it by increasing the box size (it does not change the cohesive energy) and incorporating 4 at.% Zr atoms using set command:

```# Find minimum energy fcc configuration
# Mark Tschopp, 2010

# ---------- 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```
`set        region box type/fraction 2 0.04 12543796`
```# ---------- Define Interatomic Potential ---------------------
pair_style eam/fs
pair_coeff * * Ni-Zr_Mendelev_2012.eam.fs Ni Zr
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!" ```
Can this modification be used for calculation of cohesive energy of Ni-Zr alloy?

--
With Thanks and Regards,

K Vijay Reddy
Metallurgical and Materials Engineering
National Institute of Technology
Rourkela