POSCAR for alpha-quartz

Message

tsemi · #1 Post by **tsemi** » Tue Aug 31, 2010 8:37 pm

Hi,
Anybody have a POSCAR for alpha-quartz that they could share with me?
Thank you very much,
torey

forsdan · #2 Post by **forsdan** » Tue Aug 31, 2010 9:38 pm

Positions and lattice vectors for various structures of Si02 (including the alpha structure) can be found at

http://cst-www.nrl.navy.mil/lattice/struk/sio2.html

Cheers,
/Dan
<span class='smallblacktext'>[ Edited Tue Aug 31 2010, 11:40PM ]</span>

vvxifeng16 · #3 Post by **vvxifeng16** » Wed Sep 01, 2010 7:39 am

What are you size?because you need tell me

tsemi · #4 Post by **tsemi** » Tue Sep 07, 2010 4:32 pm

I'm trying to model a 2x2x2 conventional cell. Thanks, and thanks Dan!

schani · #5 Post by **schani** » Thu Sep 09, 2010 8:20 am

If you are doing defect calculations, then maybe an orthorhombicly projected alpha quartz cell would be the best thing.

tsemi · #6 Post by **tsemi** » Thu Jan 20, 2011 7:45 pm

Hi, I'm trying to set up a POSCAR for alpha-quartz, with a=b=9.826 ang and c=10.810 ang. For angles, alpha=beta=90, gamma=120.
I have Cartesian coordinates for the atoms (there are 24 Si and 48 O) but I do not know how to set up the lattice vectors when the angles are different.
Can anyone help?
Thank you,
torey