Dear Siesta user,
I want to do phonon calculation of PtN2 in pyrite structure with 12 atoms per
unit cell. I am using LDA functional, with mesh cutoff 30 Ry. I want the phonon
dispersion in the entire Brillouin zone of the compound. So before doing the
calculation, I have certain queries
1. What parameter I have to choose for
SuperCell_1
SuperCell_2
SuperCell_3
If I choose 1, 1, 1 it cost me 324 atoms, is if enough for the calculation. And
if i choose 2,2,2 then it cost me 1500 atoms, which I think impossible to do
with say even 32 processors.???
2. What value of mesh cutoff i have to take?? The one which I optimised for
electronic structure calculation or more than that??
3. For Pt I am using DZP of 6s and DZ for 5d and for N DZP 2s, DZ 2p and SZ
3d?? This I already optimised for electronic calculation. But I think for
phonon calculation it cost me more time. So can i reduce the DZ basis set to
SZ??
4. Is there any way to reduce the time of calculation for phonon, bcoz I tried
with 1,1,1 supercell (324 atoms) with 1000 Ry, but it is not only taking time
but the scf didnt converge.
So do I have to take larger supercell?? or I should reduce the value of Mesh
cutoff to less value??
Please help me in this regard
It will be very kind of you all...
thanks
Bipul Rakshit
SRF DAE-BRNS
Computational Research Lab.
Barkatullah University,
Bhopal 462 026, India
Mob.: +919406540952
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