# The units we assume we'll use. The kim-lammps-preprocessor may swap this line out if # running against a Simulator Model whose units are not 'metal' units metal # Set logfile log output/lmp_T253.15.log # Variables that can be adjusted by kim-lammps-preprocessor to switch unit sets for # Simulator Models variable _u_distance equal 1.0 variable _u_energy equal 1.0 variable _u_mass equal 1.0 variable _u_time equal 1.0 variable _u_pressure equal 1.0 variable _u_temperature equal 1.0 # This line may be swapped out by kim-lammps-preprocessor if running against a Simulator # Model whose atom_style is not 'atomic' atom_style atomic # periodic boundary conditions along all three dimensions boundary p p p # Set neighbor skin variable neigh_skin equal 2.0*${_u_distance} neighbor ${neigh_skin} bin # create a supercell with cubic lattice (fcc, bcc, sc, or diamond) # using 10*10*10 conventional (orthogonal) unit cells variable latticeconst_converted equal 3.3040000051260003*${_u_distance} lattice bcc ${latticeconst_converted} region simbox block 0 10 0 10 0 10 units lattice create_box 1 simbox create_atoms 1 box variable mass_converted equal 180.9479*${_u_mass} # specify which KIM Model to use pair_style kim EAM_Dynamo_RaveloGermannGuerrero_2013Ta1_Ta__MO_816821594689_000 pair_coeff * * Ta mass 1 ${mass_converted} # initial volume variable v equal vol # assign formula variable V0 equal ${v} # evaluate initial value variable V0_metal equal ${V0}/(${_u_distance}*${_u_distance}*${_u_distance}) variable V0_metal_times1000 equal ${V0_metal}*1000 print "Initial system volume: ${V0_metal} Angstroms^3" # set the time step to 0.001 picoseconds variable timestep_converted equal 0.001*${_u_time} timestep ${timestep_converted} variable temp_converted equal 253.15*${_u_temperature} variable Tdamp_converted equal 0.1*${_u_time} variable press_converted equal 0.0*${_u_pressure} variable Pdamp_converted equal 1*${_u_time} # create initial velocities consistent with the chosen temperature velocity all create ${temp_converted} 17 mom yes rot yes # set NPT ensemble for all atoms fix ensemble all npt temp ${temp_converted} ${temp_converted} ${Tdamp_converted} & iso ${press_converted} ${press_converted} ${Pdamp_converted} # compute the time averages of pressure, temperature, and volume, respectively # ignore the first 5000 timesteps variable etotal_metal equal etotal/${_u_energy} variable pe_metal equal pe/${_u_energy} variable T_metal equal temp/${_u_temperature} variable V_metal equal vol/(${_u_distance}*${_u_distance}*${_u_distance}) variable P_metal equal press/${_u_pressure} fix avgmyTemp all ave/time 5 20 100 v_T_metal ave running start 5000 fix avgmyPress all ave/time 5 20 100 v_P_metal ave running start 5000 fix avgmyVol all ave/time 5 20 100 v_V_metal ave running start 5000 # extract fix quantities into variables so they can be used in if-else logic later. variable T equal f_avgmyTemp variable P equal f_avgmyPress variable V equal f_avgmyVol # set error bounds for temperature and pressure in original metal units (K and bar) variable T_low equal "253.15 - 0.2" variable T_up equal "253.15 + 0.2" variable P_low equal "0.0 - 0.2" variable P_up equal "0.0 + 0.2" # print to logfile every 1000 timesteps thermo_style custom step etotal v_etotal_metal pe v_pe_metal & temp v_T_metal vol v_V_metal press v_P_metal thermo 1000 # Run a simulation for at most 2000*1000 timesteps. At each 1000th time step, check # whether the temperature and pressure have converged. If yes, break. label top variable a loop 2000 run 1000 if "${V_metal}>${V0_metal_times1000}" then "jump SELF unstable" if "${T}>${T_low} && ${T}<${T_up} && ${P}>${P_low} && ${P}<${P_up}" then "jump SELF break" print "flag: Temp = ${T}, Press = ${P}" next a jump SELF top label break # Write final averaged volume to file if temperature and volume have converged; otherwise wirte a # flag to indicate non-convergence. variable myStep equal step if "${myStep} < 2000000" then "print '${V}' file output/vol_T253.15.out" & else "print 'not_converged' file output/vol_T253.15.out" print "LAMMPS calculation completed" quit 0 # unstable label unstable print "ERROR: System volume ${V_metal} A^3 has become larger than ${V0_metal_times1000} A^3. Aborting calculation."