> You mean Wyckoff position 8a as (0, 0, 0) right? I tried that before, No, we mean the second setting and for this setting the coordinates of position 8a are (1/8,1/8,1/8).
Alternatively, just use instead of the spacegroup the latrtice type "F" and specify the Si atoms at (0,0,0) and (.25,.25,.25) During initialization, sgroup should complain and generate a struct file compatible with WIEN2k. PS: I remember that I was quite confused myself as young researcher, that the common spacegroup-symbol + Wyckoff position is not necessarily sufficient to define a structure, but there are 2 different settings. > but the structure I see using Xcrysden was even more wrong. If I do > that, the file looks like > > Space group 227_Fd-3m > > a = 5.43 b = 5.43 c = 5.43 > 90 90 90 > > Atom 1 Si z = 14 RMT 1.8 > pos 1 x = 0.0 0.0 0.0 > pos 2 x = 0.0 0.25 0.25 > pos 3 x = 0.0 0.25 0.25 > pos 4 x = 0.0 0.25 0.25 > > It is a big change for me to work with space groups from lattice vectors. > > > For RMT sizes, I could not increase them because of the error I get from > the first step (x nn). I'm thinking that I am getting these errors > because my structure is not correct. Also, even though I increase them, > when I hit "set automatically RMT" it reduces it back to 1.8. > > > > On 6/14/2010 7:11 AM, Gerhard Fecher wrote: >> why are you giving two atoms for the basis of Si ? >> Set up 2 (see Peters remark) of spacegroup 229 should have only one on >> Wyckoff position 8a. >> >> did you recognize something from youre RMT sizes ? >> >> I usually use this example for my students to check if they know about >> crystal structures and >> to find out how they turn semiconductors into metals >> >> Ciao >> Gerhard >> >> ==================================== >> Dr. Gerhard H. Fecher >> Institut of Inorganic and Analytical Chemistry >> Johannes Gutenberg - University >> 55099 Mainz >> ________________________________________ >> Von: wien-bounces at zeus.theochem.tuwien.ac.at >> [wien-bounces at zeus.theochem.tuwien.ac.at]" im Auftrag >> von"Jedo [jedokim at umich.edu] >> Gesendet: Montag, 14. Juni 2010 12:35 >> An: wien at zeus.theochem.tuwien.ac.at >> Betreff: Re: [Wien] silicon structure >> >> Thanks for the answer. Still, I don't understand why WIEN2k is giving me >> a structure with this many atoms. I'm listing the Strucgen atoms when I >> save it. It adds 10 more atoms. The fractional coordinates look ok, but >> when I look at the structure using Xcrysden, it does not look right. I >> can send you the screen shot if you wish. >> Thanks for all the help. >> >> Space group 227_Fd-3m >> >> a = 5.43 b = 5.43 c = 5.43 >> 90 90 90 >> >> Atom 1 Si z = 14 RMT 1.21 >> pos 1 x = 0.0 0.0 0.0 >> pos 2 x = 0.0 0.25 0.25 >> pos 3 x = 0.0 0.25 0.25 >> pos 4 x = 0.0 0.25 0.25 >> >> Atom 2 Si x = 14 RMT 1.21 >> pos 1 0.25 0.25 0.25 >> pos 2 0.75 0.75 0.75 >> pos 3 0.75 0.5 0.5 >> pos 4 0.25 0.0 0.0 >> pos 5 0.0 0.0 0.25 >> pos 6 0.5 0.5 0.75 >> pos 7 0.5 0.75 0.5 >> pos 8 0.0 0.25 0.0 >> >> >> >> >> On 6/14/2010 12:59 AM, Peter Blaha wrote: >>> Nothing is wrong. >>> sgroup changes your input structure and shifts the origin to an >>> inversion center. This moves the Si atoms by (1/8,1/8,1/8). >>> >>> PS: The spacegroup 227 has 2 different "settings", i.e. origins with >>> tetrahedral symmetry or with inversion symmetry. Since all matrix >>> elements >>> can be kept as "real" numbers when inversion symmetry is present, WIEN2k >>> adopts automatically this setting. >>> >>> Jedo schrieb: >>>> Hi, >>>> >>>> I'm a newbie to wien2k. I have done some abinit calculation with >>>> silicon. So, I just wanted to start with Silicon again to test it. >>>> However, when I put the structure in, it gives me a very different >>>> structure. I'm not sure what I am doing wrong. My inputs for >>>> StructGen for Silicon is >>>> >>>> Spacegroup 227_Fd-3m >>>> Lattice parameters A 5.43 5.43 5.43 >>>> 90 90 90 >>>> >>>> Si 0 0 0 >>>> Si 0.25 0.25 0.25 >>>> >>>> Is this correct? I'm used to inputing lattice vectors. >>>> Thanks for the help >>>> >>>> Jedo >>>> >> -- >> ================================ >> Jedo Kim, Ph.D Candidate >> Heat Transfer Physics Laboratory >> 2350 Hayward, 2186 GG Brown Bldg. >> University of Michigan, Ann Arbor, MI 48109-2143 >> Email: jedokim at umich.edu, jdzbox at hotmail.com >> Tel: 734-764-3487 (o); 734-276-8370 (cell) >> http://sitemaker.umich.edu/kaviany >> ================================ >> >> _______________________________________________ >> Wien mailing list >> Wien at zeus.theochem.tuwien.ac.at >> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien >> _______________________________________________ >> Wien mailing list >> Wien at zeus.theochem.tuwien.ac.at >> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien >> >> > -- Peter Blaha Inst.Materialchemie, TU Wien Getreidemarkt 9 A-1060 Vienna Austria
