The 2Doptimize package is developed by Jamal Morteza to optimize the hexagonal and tetragonal structures.
The package allows to optimize the volume and the c/a ratio.
 To download the guide click on the link below:


We will test the example used in the guide: Mg


Execution:
 
- Create the Mg.struct file and copy the following information in it
 
 
 Mg                                                         
H   LATTICE,NONEQUIV.ATOMS:  1 194_P63/mmc                  
MODE OF CALC=RELA unit=bohr
  6.066023  6.066023  9.851222 90.000000 90.000000120.000000
ATOM  -1: X=0.33333333 Y=0.66666667 Z=0.75000000
          MULT= 2          ISPLIT= 8
ATOM  -1:X= 0.66666667 Y=0.33333333 Z=0.25000000
Mg         NPT=  781  R0=0.00010000 RMT=    2.5000   Z: 12.0
LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
                     0.0000000 1.0000000 0.0000000
                     0.0000000 0.0000000 1.0000000
   0      NUMBER OF SYMMETRY OPERATIONS
Select R_Kmax = 8 , L_max = 9, XC = pbe,and nkpoint = 3000
 
Select order of fit 5 and default parameters for volume and c/a changes.
 
Since Mg is not spin-polarized system, it is not necessary to modify Doptimize.job
file and you can run it.
 
After running 2Doptimize.job file and ana2D_lapw, you will find the below values
in Terminal and Mg.outputeos file.



 
Procedure:

- list the working repertory 
username@machinename:~/Mg$ ls
 Mg.struct
- run the command ""init_lapw" 
username@machinename:~/Mg$ init_lapw ---> normal initialization
 

NB: It's preferable to create a session and do the initialization in the w2web interface and do the following in terminal.

- Execute the command " set2D_lapw" 
username@machinename:~/Mg$ set2D_lapw ---> to setup the calculation
  
accept the default values

 
-  Modify the script 2Doptimize.job according to your needs ----> this time don't modify

 - Run the script 
username@machinename:~/Mg$ 2Doptimize.job --->
( the SCF calculation is running for the different structures : it takes much time)

- Execute the command "ana2D_lapw" 
username@machinename:~/Mg$ ana2D_lapw ---> to analyse the results

( accepts the default values and reply by yes )


The results are in the file   Mg.outputeos
 Equation of state: EOS2 (PRB52,8064)        info           7
 a,b,c,d      -798.113831        24.000954      -314.314396      1037.976992
 V0,B(GPa),BP,E0       291.9146        39.4517         4.0088

 Equation of state: Murnaghan                info           7
 E=E0+[B*V/BP*(1/(BP-1)*(V0/V)**BP +1)-B*V0/(BP-1)]/14703.6
 Pressure=B/BP*((V0/V)**BP -1)
 V0,B(GPa),BP,E0       291.8967        39.7076         4.3367       -798.082679
         vol       energy         de(EOS2)      de(Murnaghan)  Pressure(GPa)
     282.5344     -798.082250     0.000001     0.000001          1.390
     298.2308     -798.082496    -0.000003    -0.000004         -0.814
     313.9271     -798.080709     0.000005     0.000007         -2.478
     329.6235     -798.077343    -0.000004    -0.000005         -3.751
     345.3198     -798.072796     0.000001     0.000001         -4.739
                  Sigma:          0.000003     0.000004

 Equation of state: Birch-Murnaghan                info           7
 E = E0 + 9/16*(B/14703.6)*V0*[(eta**2-1)**3*BP + (eta**2-1)**2*(6-4*eta**2)]
        --> eta = (V0/V)**(1/3)
 Pressure = 3/2*B*(eta**7 - eta**5)*(1 + 3/4*(BP-4)*[eta**2 - 1])
 V0,B(GPa),BP,E0       291.9128        39.4672         4.0326       -798.082676
         vol       energy         de(Birch-Murnaghan)  Pressure(GPa)
     282.5344     -798.082250     0.000001                1.377
     298.2308     -798.082496    -0.000003               -0.809
     313.9271     -798.080709     0.000005               -2.479
     329.6235     -798.077343    -0.000004               -3.755
     345.3198     -798.072796     0.000001               -4.729
                  Sigma:          0.000003



In Terminal:
 #####################################
Vol-opt= 309.5921 ,  coa-opt= 1.6295

a0= 6.03117 , c0= 9.82779 bohr
a0= 3.1915 , c0= 5.2006 Ang

##################################### 

You may find the optimal values for the lattice paramets for different fit orders in the file "fitorder".

 #####################################
Order of fit 3
a0= 6.03240 , c0= 9.82376 bohr
a0= 3.1922 , c0= 5.1985 Ang

#####################################
Order of fit 4
a0= 6.03265 , c0= 9.82296 bohr
a0= 3.1923 , c0= 5.1980 Ang

#####################################
Order of fit 5
a0= 6.03117 , c0= 9.82779 bohr
a0= 3.1915 , c0= 5.2006 Ang

#####################################