[Wien] cohesive-energy

[tran at theochem.tuwien.ac.at]

Hi,

Yes you can choose P instead of F. Beside this, it is important
to reduce the symmetry (e.g., from cubic to orthorhombic) for
atoms with an open shell (most free atoms are magnetic) in order to reach
the proper electronic ground state. I attached the struct file (P) that I
used for a free Na atom. Usually, a box of 12x12x12 angstrom is large
enough except for the heavy alkali and alkali-earth atoms.

For RMT and RKMAX, you have to test. It is important to choose the same
parameters for the bulk and free atom.

F. Tran

On Mon, 17 Aug 2015, Seyyed Amir Abbas Emami wrote:

> ​Dear users.
> 
> I am trying to calculate cohesive energy. As it is mentioned in FAQ, we must create FCC supercell and also use identical RKmax and RMT. Now i have two question?
> 
> 1- Can i choose Cubic (P) supercell instead of FCC. In other words, is there any reason for that choosing?
> 2- what is the good or best value for RKmax or RMT. (actually i automatically chose RMT for one element equal to 2.5 and consequently RKmax also 2.5. Is this value valid?)
> 
> 
> Thank you in advance.
> 
> 
>
-------------- next part --------------
Na                                                                             
P   LATTICE,NONEQUIV.ATOMS:  1                                                 
MODE OF CALC=RELA unit=ang                                                     
 22.676723 22.771209 22.865695 90.000000 90.000000 90.000000                   
ATOM  -1: X=0.00000000 Y=0.00000000 Z=0.00000000
          MULT= 1          ISPLIT= 8
Na         NPT=  781  R0=0.00010000 RMT=    2.0000   Z: 11.0                   
LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
                     0.0000000 1.0000000 0.0000000
                     0.0000000 0.0000000 1.0000000
   8      NUMBER OF SYMMETRY OPERATIONS
-1 0 0 0.00000000
 0-1 0 0.00000000
 0 0-1 0.00000000
       1
-1 0 0 0.00000000
 0-1 0 0.00000000
 0 0 1 0.00000000
       2
-1 0 0 0.00000000
 0 1 0 0.00000000
 0 0-1 0.00000000
       3
-1 0 0 0.00000000
 0 1 0 0.00000000
 0 0 1 0.00000000
       4
 1 0 0 0.00000000
 0-1 0 0.00000000
 0 0-1 0.00000000
       5
 1 0 0 0.00000000
 0-1 0 0.00000000
 0 0 1 0.00000000
       6
 1 0 0 0.00000000
 0 1 0 0.00000000
 0 0-1 0.00000000
       7
 1 0 0 0.00000000
 0 1 0 0.00000000
 0 0 1 0.00000000
       8