### This lammps-script was used for calculation of melting line (Fe and Al) in work
### Starikov S.V., Stegailov V.V. Premelting of iron and aluminum: implication for 
### high-pressure melting curve measurements // Phys. Rev. B., 2009, V. 80, P. 220104(R)
###
### calculation of melting temperature of aluminum  at low pressure

dimension 	3
boundary	p p p
units		metal

atom_style	atomic
neighbor	0.3 bin
neigh_modify	every 20 delay 0 check no

### T0 - initial temperatura of calculation
### Given temperature ${realT0} devided to 2.2 must be some bigger than expected melting temperature Tm 

variable	T0 equal 1070
variable	realT0 equal ${T0}*2.2
variable	Tm equal 950

### x - number of crystal cell in x-direction 
### a - lattice constant
### l - size of calculation cell in x-direction

variable	x equal 45
variable	a equal 4.05
variable	l equal $x*$a

lattice		fcc $a
#lattice		hcp $a
#lattice		bcc $a

region		box block 0 $x 0 15 0 15
create_box	1 box
create_atoms	1 box

mass		1 26.98

pair_style	eam/alloy 
pair_coeff	* * /home/user/alcu.foiles.eam.alloy.txt Al  

velocity	all create ${realT0} 481516

dump		id all cfg 2500 /home/user/dump/al_melt_1.*.cfg id type xs ys zs        
dump_modify	id element Al

timestep	0.0005
thermo_style	custom step temp etotal pe press pxx pyy pzz vol
thermo		30

### Equilibration with or without Langevin thermostat
fix		1 all nve
#fix		2 all langevin ${T0} ${T0} 20 481516
run		3000 
unfix		1
#unfix		2

lattice		sc 1.00

variable	d1 equal $l*0.225
variable	d2 equal $l*0.275

region		del block ${d1} ${d2} -10 100 -10 100
delete_atoms	region del

variable	h equal $l*0.5


region		liquid block -10 $h -10 100 -10 100
group		liquid region liquid

### Creation of two-phase system
fix		3 liquid nve
run		50000
unfix		3

velocity	all create ${Tm} 481516

fix		4 all nve
run		50000 
unfix		4


#write_restart	/home/user/equilibrium.restart

### main calculation

variable	len equal $l*0.95

region		twophase block 5 ${len} -10 100 -10 100
group		twophase region twophase
fix		5 twophase nve
run		100000 
		
#write_restart	/home/user/end.restart

### The analysis about accuracy of the initial estimation of melting temperature Tm can be perfermed by change of temperature,
### visually observation of phase interface or on the basis of parameter of order [Phys.Rev.B., 2009, V.80, P.220104(R)]