POSCAR file

Queries about input and output files, running specific calculations, etc.


Moderators: Global Moderator, Moderator

Post Reply
Message
Author
yilmaz
Newbie
Newbie
Posts: 18
Joined: Wed Aug 10, 2005 7:56 pm
License Nr.: jk35QGB7
Location: puerto rico

POSCAR file

#1 Post by yilmaz » Fri Aug 12, 2005 6:02 pm

hi
i need to consider atleast 150 atoms in the "supercell" i use and i have no idea what are the lattice vectors for that "supercell", which can fill up the space.
how can a ugly shape without any symmetry can be defined with three vector anyway?
if the "supercell" is made of fcc "unit cells" can i use that unit cell vectors for "supercell".?
may be i am thinking in a wrong way. please some help.

i have already looked at the examples in the workshops but no clue.
thank you.
Last edited by yilmaz on Fri Aug 12, 2005 6:02 pm, edited 1 time in total.

admin
Administrator
Administrator
Posts: 2921
Joined: Tue Aug 03, 2004 8:18 am
License Nr.: 458

POSCAR file

#2 Post by admin » Wed Aug 17, 2005 1:12 pm

I suggest to construct the supercell by repeating one primitive cell
LxMxN times in 3D, by giving multiples of the lattice vetors which define the Bravais matrix accordingly.
e.g. for a simple cubic cell, extended to a LxMxN box, this would read
...
a_0 (lattice parameter of the primitive cell)
L 0.0 0.0
0.0 M 0.0
0.0 0.0 N
....
The specification of the positions of the atoms then depends on
whether you choose 'Direct' (re-scale with L,M and N) or 'Carthesian' please have a look at the online manual
http://cms.mpi.univie.ac.at/vasp/vasp/node63.html
concerning the specification of the atoms' positions.
Last edited by admin on Wed Aug 17, 2005 1:12 pm, edited 1 time in total.

Post Reply