<DIV class=MsoNormal style="MARGIN: 0in 0in 0pt"><FONT face="Times New Roman" size=3>Dear Prof. Blaha,</FONT></DIV> <DIV class=MsoNormal style="MARGIN: 0in 0in 0pt"><FONT size=3><FONT face="Times New Roman"><SPAN style="mso-spacerun: yes"> </SPAN>I tried the calculation as same as in that exercise only.<SPAN style="mso-spacerun: yes"> </SPAN>I did volume optimization (-6,-3, 0, 3, 6% volume changes) with RKMAX=5 and k point=1000.<SPAN style="mso-spacerun: yes"> </SPAN>It shows that -6% volume changes gave the minimum energy value.<SPAN style="mso-spacerun: yes"> </SPAN>Then I repeated the same calculation with the RKMAX=7 and k-point=1000, this time also it shows that -6% of volume changes only gives minimum value.<SPAN style="mso-spacerun: yes"> </SPAN>By your advice I included volume changes from -9 to 9 which gave parabola with minimum energy in -6% volume changes</FONT></FONT></DIV> <DIV class=MsoNormal style="MARGIN: 0in 0in
0pt"><?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p><FONT face="Times New Roman" size=3> </FONT></o:p></DIV> <DIV class=MsoNormal style="MARGIN: 0in 0in 0pt"><FONT face="Times New Roman" size=3>I tried for RKMAX=7.2 and k-point=1000, in that case also -6% volume changes gives the minimum energy. </FONT></DIV> <DIV class=MsoNormal style="MARGIN: 0in 0in 0pt"><o:p><FONT face="Times New Roman" size=3> </FONT></o:p></DIV> <DIV class=MsoNormal style="MARGIN: 0in 0in 0pt"><FONT size=3><FONT face="Times New Roman">( In the case of TiC, RKMAX=7<SPAN style="mso-spacerun: yes"> </SPAN>and k-point =100 &1000, gives 0% volume changes gives minimum energy value.)<SPAN style="mso-spacerun: yes"> </SPAN></FONT></FONT></DIV> <DIV class=MsoNormal style="MARGIN: 0in 0in 0pt"><o:p><FONT face="Times New Roman" size=3> </FONT></o:p></DIV> <DIV class=MsoNormal style="MARGIN: 0in 0in 0pt"><FONT face="Times New Roman"
size=3>How to choose the RKMAX in such a way that to get 0% volume changes will give the minimum energy?</FONT></DIV> <DIV class=MsoNormal style="MARGIN: 0in 0in 0pt"><o:p><FONT face="Times New Roman" size=3> </FONT></o:p></DIV> <DIV class=MsoNormal style="MARGIN: 0in 0in 0pt"><o:p><FONT face="Times New Roman" size=3>Thanks in advance.</FONT></o:p></DIV> <DIV class=MsoNormal style="MARGIN: 0in 0in 0pt"><o:p></o:p> </DIV> <DIV class=MsoNormal style="MARGIN: 0in 0in 0pt"><FONT face="Times New Roman" size=3>With regards,</FONT></DIV> <DIV class=MsoNormal style="MARGIN: 0in 0in 0pt"><FONT face="Times New Roman" size=3>Santhy Jaiker</FONT></DIV><BR><BR><B><I>Peter Blaha <pblaha@theochem.tuwien.ac.at></I></B> wrote: <BLOCKQUOTE class=replbq style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">Why did you increase RKMAX to touching spheres ?<BR>Of course then you cannot do a volume optimization.<BR><BR>If you follow the instructuions
on this "exercises" it tells you you must do <BR>these convergence tests for all volume points in your curve.<BR><BR>Then you have just tested k-points, but not RKMAX !<BR><BR><BR>> By Prof.Blaha’s advice, I added few more negative volumes and then I <BR>> plotted the results, it gave nice parabola and shows that at -6 only <BR>> gives the min. energy. <BR>> <BR>> Then I checked the accuracy test to k-point, I repeated the calculation <BR>> with 1000, 2000 and 3000 for k point. I listed result below,<BR>> k-point RKM Enegry Volume<BR>> *1000 6.93 -1707.621751 <BR>> 113.36162*<BR>> 2000 6.99 -1707.621552 ,,<BR>> 3000 6.61 -1707.621562 ,,<BR>> <BR>> Therefore, for Ti-bcc system with RMT=2.5, RKMAX=7, RKM=6.93, GMAX=12 <BR>> and k-point =1000 gives the optimized structure with volume V=113.36161 <BR>> (a = 3.226757A) and E=-1707.621751Ry. Is it correct?<BR>> <BR>> <BR>> In the above calculation, I used RMT of Ti is
2.5(default). From the <BR>> mailing list (site: <BR>> http://zeus.theochem.tuwien.ac.at/pipermail/wien/2004-April/002424.html)<BR>> I changed the RMT of Ti from 2.5 to 2.69 (because nn-distance = 5.39080).<BR>> I used remaining parameters as same as the above calculation (RKMAX=7, <BR>> GMAX=12 and k-point=1000). Using this data, I am able to run SCF, but <BR>> not volume optimization with negative volumes because RMT is close to <BR>> nn-distance (positive volumes give higher energy and it is not possible <BR>> to get a parabola here). This calculation is almost look like single <BR>> point energy calculation (i.e. it gives the energy of the given <BR>> structure) and there is not much energy difference from the above <BR>> calculation. I listed the result below. <BR>> <BR>> RMT=2.69, RKMAX=7, RKM=6.89, GMAX=12 and k-point =1000<BR>> V=120.59737 (a = 3.294) and E=-1707.621713Ry<BR>> <BR>> Then how can I do the
optimization?<BR>> <BR>> Thanks in advance.<BR>> <BR>> With regards,<BR>> Santhy Jaiker<BR>> <BR>> <BR>> <BR>> */Peter Blaha <PBLAHA@THEOCHEM.TUWIEN.AC.AT>/* wrote:<BR>> <BR>> Hi,<BR>> <BR>> I hope it is clear that you CANNOT use min_lapw for your bcc Ti example.<BR>> <BR>> With respect to the volume optimization, I don't see anything bad.<BR>> <BR>> Specifying RKMAX does not fix RKMAX to this value, it just guarantees<BR>> that it does not get bigger than what you specified, but when changing<BR>> the lattice parameter, it is natural that RKMAX changes.<BR>> <BR>> You shoulds add a few more negative volumes (-9 -12 maybe -15) and then<BR>> plot the results because it seems the minimum is near -6. When you<BR>> get a<BR>> nice parabola it seems ok, if not it may happen because of too low<BR>> RKMAX<BR>> (gotro 7.5, 8, up to 9) or to few k-points (100 is very little).<BR>> <BR>> > I am a
new user of wien2k. I had gone through the FAQ and L.D. Marks<BR>> > notes for optimization. I started with small system like Ti-BCC.<BR>> > Before going to mini_lapw, I tried the accuracy test as same as<BR>> given<BR>> > in the site http://www.wien2k.at/events/ws2006/Exercises.pdf.<BR>> ><BR>> > I gave lattice parameter= 3.294A°, RMT=2.5(default),<BR>> RKMAX=7(default),<BR>> > k-point=1000 and Gmax=12(default) for Ti-BCC system. I tried the<BR>> same<BR>> > step in the above site,<BR>> > STEP 1: run x optimize and generate 5 structures (-6, -3, 0, 3, 6 %<BR>> > volume change)<BR>> > STEP2: edit “optimize.job”.<BR>> > STEP3: run optimize.job and plot the results.<BR>> > I got<BR>> > SCF File RKM Energy<BR>> > Vol -6.0.scf *6.93 -1707.621717*<BR>> > Vol -3.0.scf 6.85 -1707.621662<BR>> > Vol 0.0.scf 6.79 -1707.621239<BR>> > Vol 3.0.scf 6.72 -1707.619926<BR>>
> Vol 6.0.scf 6.65 -1707.618133<BR>> ><BR>> > Energy is high when RKM is 6.93. Since I changed RKMAX=6.93 in<BR>> Ti.in1<BR>> > file and I didn’t change any other parameter. I repeated those 3<BR>> steps.<BR>> > I got<BR>> ><BR>> > SCF File RKM Energy<BR>> > Vol -6.0.scf *6.93 -1707.620994*<BR>> > Vol -3.0.scf 6.85 -1707.620941<BR>> > Vol 0.0.scf 6.79 -1707.620476<BR>> > Vol 3.0.scf 6.72 -1707.619422<BR>> > Vol 6.0.scf 6.65 -1707.617423<BR>> ><BR>> > Here I observed that even though same RKMAX (=6.93) gives different<BR>> > energy. And I couldn’t keep RKMAX as constant. Since, during SCF<BR>> > calculation it changes.<BR>> ><BR>> > Sorry I took more of your time. I have some experience to handle<BR>> CASTEP<BR>> > (in windows mode). But I couldn't correlate things in WIEN2k.<BR>> ><BR>> > It will be really helpful, if you tell, how to do the
accuracy<BR>> test for<BR>> > RKMAX.<BR>> ><BR>> > Thanks in advance.<BR>> ><BR>> > Santhy Jaiker<BR>> ><BR>> ><BR>> ><BR>> ------------------------------------------------------------------------<BR>> > Here’s a new way to find what you're looking for - Yahoo! Answers<BR>> ><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>> 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>> with love,<BR>> K. Santhy<BR>> <BR>>
**********************************************<BR>> A truly happy person is one<BR>> who can enjoy the scenery on a detour<BR>> **********************************************<BR>> <BR>> Send free SMS to your Friends on Mobile from your Yahoo! Messenger. <BR>> Download Now! http://messenger.yahoo.com/download.php<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><BR>P.Blaha<BR>--------------------------------------------------------------------------<BR>Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna<BR>Phone: +43-1-58801-15671 FAX: +43-1-58801-15698<BR>Email: blaha@theochem.tuwien.ac.at WWW:
http://info.tuwien.ac.at/theochem/<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><BR><BR>with love,<br> K. Santhy<br> <br style="color: rgb(191, 95, 0);"><span style="color: rgb(185, 185, 185);"> **********************************************</span><br style="color: rgb(185, 185, 185);"><span style="color: rgb(185, 185, 185);"> A truly happy person is one</span><br style="color: rgb(185, 185, 185);"><span style="color: rgb(185, 185, 185);"> who can enjoy the scenery on a detour</span><br style="color: rgb(185, 185, 185);"><span style="color: rgb(185, 185, 185);"> **********************************************</span><br><p> 
<hr size=1></hr>
Here’s a new way to find what you're looking for - <a href="http://us.rd.yahoo.com/mail/in/yanswers/*http://in.answers.yahoo.com/">Yahoo! Answers</a>