On Tue, 4 Sep 2007, bipul rakshit wrote:
| hello siesta user,
| i am doing calculations on Sn (tin)...
| i do the convergence test for mesh cutoff and monhorsk pack.....
| the cubic Sn converges at 8x8x8 and mesh cutoff of 268 Ry. Since i use 8
atoms per unit cell so i get 512 atoms (auxillary supercell 4x4x4)
|
| Now my question is
| 1. when i run siesta with the above parameters and at the end of the file
the energy it give is the energy of 512 atoms or what????
Dear Bipul,
the total energy is given
per the number of atoms you really have in your cell, i.e. 8 in your case.
The auxillary supercell is an artificial construction to facilitate
keeping trace on overlaps across the cell boundary, in systems with
periodicity.
| 2. If its the energy of 512 atoms then how to find the energy of single
atom, in the same volume occupied by a single atom??
To get total energy per atom, you divide your result by 8.
I don't quite understand "in the same volume occupied by a single atom".
All all 8 atoms structurally equivalent?
Best regards,
Andrei
+-- Dr. Andrei Postnikov ---- Tel. +33-387315873 ----- mobile +33-666784053 ---+
| Paul Verlaine University - Institute de Physique Electronique et Chimie, |
| Laboratoire de Physique des Milieux Denses, 1 Bd Arago, F-57078 Metz, France |
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