# Charge regulation lammps for simple weak electrolyte

units           lj
atom_style      charge
neighbor        3.0 bin
read_data       data.chreg-acid

variable        cut_long equal 12.5
variable        nevery equal 100
variable        nmc equal 100
variable        pH equal 7.0
variable        pKa equal 6.0
variable        pIm equal 3.0
variable        pIp equal 3.0

variable        cut_lj equal 2^(1.0/6.0)
variable        lunit_nm equal 0.72 # in the units of nm
velocity        all create 1.0 8008 loop geom

pair_style      lj/cut/coul/long ${cut_lj} ${cut_long}
pair_coeff      * *  1.0 1.0
kspace_style    ewald 1.0e-3
pair_modify     shift yes

#########  VERLET INTEGRATION WITH LANGEVIN THERMOSTAT  ###########
fix             fnve all nve
compute         dtemp all temp
compute_modify  dtemp dynamic yes
fix             fT all langevin 1.0 1.0 1.0 123
fix_modify      fT temp dtemp

fix chareg      all charge/regulation 2 3 acid_type 1 pH ${pH} pKa ${pKa} pIp ${pIp} pIm ${pIm} lunit_nm ${lunit_nm} nevery ${nevery} nmc ${nmc} seed 2345 tempfixid fT
thermo          100
thermo_style custom step pe c_dtemp f_chareg[1] f_chareg[2] f_chareg[3] f_chareg[4] f_chareg[5] f_chareg[6] f_chareg[7] f_chareg[8]
timestep        0.005
run             2000