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lammps/examples/ELASTIC_T/BORN_MATRIX/Silicon/init.in
2022-02-25 15:25:47 -07:00

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# NOTE: This script can be modified for different atomic structures,
# units, etc. See in.elastic for more info.
#
# Define MD parameters
# These can be modified by the user
# These settings replicate the 1477~K benchmark of
# Kluge, Ray, and Rahman (1986) that is Ref.[15] in:
# Y. Zhen, C. Chu, Computer Physics Communications 183(2012) 261-265
# select temperature and pressure (lattice constant)
variable temp index 1477.0 # temperature of initial sample
variable a index 5.457 # lattice constant
# select sampling parameters, important for speed/convergence
variable nthermo index 1500 # interval for thermo output
variable nevery index 10 # stress sampling interval
variable neveryborn index 100 # Born sampling interval
variable timestep index 0.000766 # timestep
variable nlat index 3 # number of lattice unit cells
# other settings
variable mass1 index 28.06 # mass
variable tdamp index 0.01 # time constant for thermostat
variable seed index 123457 # seed for thermostat
variable thermostat index 1 # 0 if NVE, 1 if NVT
variable delta index 1.0e-6 # Born numdiff strain magnitude
# hard-coded rules-of-thumb for run length, etc.
variable nfreq equal ${nthermo} # interval for averaging output
variable nrepeat equal floor(${nfreq}/${nevery}) # number of samples
variable nrepeatborn equal floor(${nfreq}/${neveryborn}) # number of samples
variable nequil equal 10*${nthermo} # length of equilibration run
variable nrun equal 100*${nthermo} # length of equilibrated run
# generate the box and atom positions using a diamond lattice
units metal
boundary p p p
# this generates a standard 8-atom cubic cell
lattice diamond $a
region box prism 0 1 0 1 0 1 0 0 0
# this generates a 2-atom triclinic cell
#include tri.in
create_box 1 box
create_atoms 1 box
mass 1 ${mass1}
replicate ${nlat} ${nlat} ${nlat}
velocity all create ${temp} 87287