<div><BR><BR> </div> <div class=MsoPlainText style="MARGIN: 0cm 0cm 0pt"><SPAN lang=EN-GB style="mso-fareast-font-family: 'MS Mincho'"><FONT face="Courier New">Hi,<SPAN style="mso-spacerun: yes"> </SPAN><BR>Thaks for the help. my problem is to generate Al2O3 supercell with vacuum slab in Wien2k.Basic inputs are given below for rhombohedral settings:<BR><BR>Cell parameters: 4.7626<SPAN style="mso-spacerun: yes"> </SPAN>4.7626<SPAN style="mso-spacerun: yes"> </SPAN>13.0032(ang) ;<SPAN style="mso-spacerun: yes"> </SPAN>90.000<SPAN style="mso-spacerun: yes"> </SPAN>90.00<SPAN style="mso-spacerun: yes"> </SPAN>90.00<BR>Space group: 167 R-3c<BR>Positions:<BR>Al:0.3519208<SPAN style="mso-spacerun: yes"> </SPAN>0.3519208 <SPAN style="mso-spacerun: yes"> </SPAN>0.3519208<BR><SPAN style="mso-spacerun: yes"> </SPAN>0.8519208<SPAN
style="mso-spacerun: yes"> </SPAN>0.8519208<SPAN style="mso-spacerun: yes"> </SPAN>0.8519208<BR><SPAN style="mso-spacerun: yes"> </SPAN>0.1480792<SPAN style="mso-spacerun: yes"> </SPAN>0.1480792<SPAN style="mso-spacerun: yes"> </SPAN>0.1480792<BR><SPAN style="mso-spacerun: yes"> </SPAN>0.6480792<SPAN style="mso-spacerun: yes"> </SPAN>0.6480792<SPAN style="mso-spacerun: yes"> </SPAN>0.6480792<BR>O: 0.9437520<SPAN style="mso-spacerun: yes"> </SPAN>0.5562480<SPAN style="mso-spacerun: yes"> </SPAN>0.2500000<BR><SPAN style="mso-spacerun: yes"> </SPAN>0.5562480<SPAN style="mso-spacerun: yes"> </SPAN>0.2500000<SPAN style="mso-spacerun: yes"> </SPAN>0.9437520<BR><SPAN style="mso-spacerun: yes">
</SPAN>0.2500000<SPAN style="mso-spacerun: yes"> </SPAN>0.9437520<SPAN style="mso-spacerun: yes"> </SPAN>0.5562480<BR><SPAN style="mso-spacerun: yes"> </SPAN>0.0562480<SPAN style="mso-spacerun: yes"> </SPAN>0.4437520<SPAN style="mso-spacerun: yes"> </SPAN>0.7500000<BR><SPAN style="mso-spacerun: yes"> </SPAN>0.4437520<SPAN style="mso-spacerun: yes"> </SPAN>0.7500000<SPAN style="mso-spacerun: yes"> </SPAN>0.0562480<BR><SPAN style="mso-spacerun: yes"> </SPAN>0.7500000<SPAN style="mso-spacerun: yes"> </SPAN>0.0562480<SPAN style="mso-spacerun: yes"> </SPAN>0.4437520<BR><BR>Thanks in advance.<BR><BR>Swati</FONT><BR></SPAN></div> <div><B><I></I></B> </div> <div><B><I></I></B> </div> <div><B><I>"B. Yanchitsky"
<yan@im.imag.kiev.ua></I></B> wrote:</div> <BLOCKQUOTE class=replbq style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">Swati,<BR><BR>Could you provide once more Al and O positions for small cell,<BR>lattice parameters,<BR>and type (size) of supercell you are needed for?<BR><BR>Regards,<BR>Bogdan Yanchitsky<BR><BR>Institute of Magnetism<BR>Vernadsky Blvd., 36-b<BR>03142 Kiev<BR>UKRAINE<BR><BR>Tel. (+380-44) 444 34 20<BR>Fax. (+380-44) 444 10 20<BR><BR><BR><BR>swati chaudhury wrote:<BR>> Hi Michael and all wien users,<BR>> <BR>> Thanks for your suggestion.<BR>> I have tried to generate Al2O3 supercell in Wien by following your <BR>> suggestion. But yet,I have not got proper result.<BR>> The structure files are attached.<BR>> (1)File a.struct : Using Wyckoffpositions (4 Al & 6 O) but without <BR>> adding transformation : lattice type selected <BR>> :H <BR>> Derived space group:193(P 63/mcm)and not the required
167R3cH<BR>> <BR>> (2) File a2.struct : Wycoff position with added transformation: <BR>> (2/3,1/3,1/3)+ -Al<BR>> (1/3,2/3,2/3)+ -O<BR>> Lattice type selected : H <BR>> Derived space group :1 P1<BR>> <BR>> (3)File A_latest.struct : Putting all 30 positions with added <BR>> transformation :<BR>> Lattice selected :P <BR>> Derived space group : 15 (C 2/c)<BR>> In no process my required space group is derived, ie 167 R-3c:H<BR>> What can I do now? Please help me.<BR>> Swati<BR>> <BR>> */Michael Fischer <DOMMIGUEL@GMX.DE>/* wrote:<BR>> <BR>> Hello,<BR>> <BR>> sorry, I was not aware that you cannot select the space group in<BR>> hexagonal setting in structgen - as I said, I do not have much<BR>> experience with rhombohedral and hexagonal cells in WIEN2k.<BR>> <BR>> I think you should do as follows: Choose H lattice type and enter the<BR>> atoms separately. You have to enter 4 aluminium and 6 oxygen
positions.<BR>> The other ones should be generated by the lattice type. In order to<BR>> find out which positions you need to enter, I suggest you use "WYCKPOS"<BR>> of www.cryst.ehu.es. There, you enter space group 167 and look at the<BR>> coordinates given for Wyckoff positions 12c (Al) and 18e (O). For x or<BR>> z, you substitute the coordinate you have calculated.<BR>> E.g. for Al at the position (0 0 0.35), i.e. z=0.35, you need to enter<BR>> the four positions:<BR>> 0 0 0.35<BR>> 0 0 0.15<BR>> 0 0 0.85<BR>> 0 0 0.65<BR>> Alternatively, select P lattice type and enter all 12 and 18 atoms<BR>> respectively (more tedious). In addition to the above, you need to<BR>> apply the transformations for all four Al and six O-positions.<BR>> (2/3,1/3,1/3) +<BR>> (1/3,2/3,2/3) +<BR>> <BR>> The cause why your second try did not work is easily explained: If you<BR>> enter only two atoms and do not choose the correct space
group,<BR>> structgen does not know how to generate the symmetry-equivalent atoms.<BR>> So you end up with a cell that has way too few atoms.<BR>> <BR>> Greetings<BR>> Michael<BR>> <BR>> _______________________________________________<BR>> Wien mailing list<BR>> Wien@zeus.theochem.tuwien.ac.at<BR>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien<BR>> <BR>> <BR>> <BR>> ------------------------------------------------------------------------<BR>> <BR>> _______________________________________________<BR>> Wien mailing list<BR>> Wien@zeus.theochem.tuwien.ac.at<BR>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien<BR><BR>_______________________________________________<BR>Wien mailing list<BR>Wien@zeus.theochem.tuwien.ac.at<BR>http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien<BR></BLOCKQUOTE><BR>