[Wien] Size of Supercell, Interaction Range--->Coordination Shell in Phonon

[Ghosh SUDDHASATTWA]

Dear Wien2k users, 

I have been getting all negative dispersion curves for an orthorhombic
supercell (12 atom, 18 atom both, 24 atom) 

Now I have taken a 3x2x1 supercell (36 atoms) {since the z lattice parameter
is 8.2 A)

Although, this question is not directly related to Wien2k, I request all
users who are doing phonon calculations 

 

In phonon software, we carry out the following for the creation of the d45
file 

1.	Define the lattice parameters (optimized before by Wien2k) (I am
using Pnma_51 space group)
2.	Define the number of displacive particles(non-equivalent atoms etc.)
3.	Define the coordinates of the displacive particles 
4.	Then we have 

a.	Interaction Range---> Coordination Shell 
b.	Interaction Range---> Supercell Size (Restore symmetry or not, +/-
displacements or not etc.)

 

Now in (a), the default is 1. How do we choose this number. Does the d45
file change if we change this number

With Pnma as space group and three in-equivalent atoms, what should I put
for a 3x2x1 supercell 

 

Thanks in advance 

 

Suddhasattwa 

 

 

 

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