[Wien] accuracy test for RKMAX

[santhy kathirvelu]

Dear Schwarz,
    I am a new user of wien2k.  I had gone through the FAQ and L.D. Marks notes for optimization.  I started with small system like Ti-BCC.  Before going to mini_lapw,  I tried the accuracy test as same as given in the site http://www.wien2k.at/events/ws2006/Exercises.pdf.
   
  I gave lattice parameter= 3.294A°, RMT=2.5(default), RKMAX=7(default), k-point=1000 and Gmax=12(default) for Ti-BCC system.  I tried the same step in the above site, 
  STEP 1: run x optimize and generate 5 structures (-6, -3, 0, 3, 6 % volume change)
  STEP2: edit “optimize.job”. 
  STEP3: run optimize.job and plot the results.  
  I got
  SCF File          RKM               Energy
  Vol -6.0.scf      6.93                 -1707.621717
  Vol -3.0.scf      6.85                 -1707.621662
  Vol 0.0.scf       6.79                 -1707.621239
  Vol 3.0.scf       6.72                 -1707.619926
  Vol 6.0.scf       6.65                 -1707.618133
   
  Energy is high when RKM is 6.93.   Since I changed RKMAX=6.93 in Ti.in1 file and I didn’t change any other parameter.  I repeated those 3 steps. I got
   
  SCF File          RKM               Energy
  Vol -6.0.scf      6.93                 -1707.620994
  Vol -3.0.scf      6.85                 -1707.620941
  Vol 0.0.scf       6.79                 -1707.620476
  Vol 3.0.scf       6.72                 -1707.619422
  Vol 6.0.scf       6.65                 -1707.617423
   
  Here I observed that even though same RKMAX (=6.93) gives different energy.  And I couldn’t  keep RKMAX as constant.  Since, during SCF calculation it changes.
   
  Sorry I took more of your time.  I have some experience to handle CASTEP (in windows mode).  But I couldn't  correlate things in WIEN2k.  
   
  It will be really helpful,  if you tell, how to do the accuracy test for RKMAX.
   
  Thanks in advance.
   
  Santhy Jaiker
   

 			
---------------------------------
 Here’s a new way to find what you're looking for - Yahoo! Answers 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://zeus.theochem.tuwien.ac.at/pipermail/wien/attachments/20070628/f094ad37/attachment.html