Dear User,
I am extremely sorry for making a big size email several times.
I have used comb3 potential on Ti for observing radiation damage. I have attached my input, log, and force field file. During the simulation, it generates only one interstitial and one vacancy and then only that interstitial move with time after that only surface atom generates a defect than inside.
Does anyone have any idea how I can fix this problem?
-------------- Initialize Simulation ------------
echo both
units metal # set ‘metal’ units (Angstrom,ps timescale)
dimension 3
boundary p p p # periodic BCs
atom_style charge
atom_modify map array
neighbor 0.5 bin
neigh_modify delay 0 every 1 check yes # neighbor command modifies potential’s natural cutoff_needed?
----------------------- ATOM DEFINITION ----------------------------
read_data Ti1.lmp
write_dump all atom all_atom.lammpstrj
--------------- Creat Atoms / Geometry -----------------------
mass 1 47.86700000
region rPKA sphere 24.597 50.1157 52.1782 1.4 # Create spherical region ‘rpka’ at x, y, x with radius (39154 particle index)
------------------Define Interatomic Potential -----------------
pair_style comb3 polar_off # Finnis-Sinclair EAM Potential from NIST
pair_coeff * * ffield.TiO.comb3 Ti #Ti # Applies Fe coefficients to all atom pairs # Ti-Ti
Groups
region rinterior sphere 51 51 51 46 # define inner box region used for simulation domain
region rexterior sphere 51 51 51 41 side out # define thermostat region outside of simulation domain
region outer intersect 2 rinterior rexterior
group interior region rinterior # define group called ‘interior’ comprised of region ‘rinterior’
group exterior region rexterior
group heatsink region outer
group PKA region rPKA
compute coordi all coord/atom cutoff 2.2
compute kin all ke/atom
compute kin_all interior ke
variable kine equal c_kin_all
compute pot all pe/atom
compute eatoms1 all reduce sum c_pot
variable pot equal c_eatoms1
compute tempk all temp
variable temp_all equal c_tempk
compute clus all cluster/atom 2.2
variable clus_all equal c_clus
compute dpa all displace/atom
compute t_dpa all reduce ave c_dpa[4] #c_dpa = sqrt(dxdx + dydy + dz*dz)
variable dpa equal c_t_dpa
variable simu_time equal “time”
compute int_vac interior voronoi/atom occupation
compute red_vac interior reduce sum c_int_vac[1] #first column vacancies=0 ; interstitials=2,3,4…ADDition gives total no. of atoms in the system
compute red_int interior reduce sum c_int_vac[2] #Second column interstitials>1 ADDition gives > natoms
variable interstitial equal “(c_red_int - c_red_vac)/2” #check for integer value#############################################
fix val1 all print 20 “{simu_time} {pot} {kine} {temp_all} {dpa} {interstitial}” file Values_20_kev_50_6.txt screen no
fix val2 all print 100 “{simu_time} {pot} {kine} {temp_all} {dpa} {interstitial}” file Values_100_kev_50_6.txt screen no
dump 1 all custom 100 test_all_6.dump type x y z c_kin c_pot c_coordi c_clus c_int_vac[1] c_int_vac[2]
dump 2 PKA custom 100 PKA_traj_init_col_6.dump type x y z c_kin c_pot c_coordi c_clus c_int_vac[1] c_int_vac[2]
thermo 20
thermo_style custom step dt temp pe etotal press vol
thermo_modify lost warn line one flush yes format 1 “ec %8lu” format float “%20.10g”
log.lammps (334 KB)