Queries about input and output files, running specific calculations, etc.
Moderators: Global Moderator, Moderator
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rudra-b
#1
Post
by rudra-b » Wed Oct 21, 2009 8:50 am
Dear Colleagues,
while trying to get the AFM Ground state for Cr dimer (cluster) i am facing a great problem. My INCAR is:
Code: Select all
SYSTEMÂ =Â Cr2
ISTARTÂ Â Â =Â Â Â 1
LORBITÂ Â Â =Â Â Â 11
EDIFFÂ Â Â Â =Â Â Â 0.0001
EDIFFGÂ Â Â =Â Â -0.01
IBRIONÂ Â Â =Â Â Â 1
NSWÂ Â Â Â Â Â =Â Â Â 100
POTIMÂ Â Â Â =Â Â Â 0.5
ISMEARÂ Â Â =Â Â Â 0
SIGMAÂ Â Â Â =Â Â Â 0.01
ISPINÂ Â Â Â =Â Â Â 2
VOSKOWNÂ Â =Â Â Â 1
MAGMOMÂ Â Â =Â Â +6Â Â -6
IALGOÂ Â Â Â =Â Â Â 48
LDIAGÂ Â Â Â =Â Â Â .TRUE.
NELMÂ Â Â Â Â =Â Â 40
NELMINÂ Â Â =Â Â Â 4
NELMDLÂ Â Â =Â Â Â -5
#-------------    save memory--------------
ISYMÂ Â Â Â Â =Â Â Â Â 0
LCHARGÂ Â Â =Â Â .FALSE.
LELFÂ Â Â Â Â =Â Â .FALSE.
LWAVEÂ Â Â Â =Â Â .TRUE.
and POSCAR is:
Code: Select all
Cr2
    1.000000000000000
    14.0000000000000000    0.0000000000000000    0.0000000000000000
     0.0000000000000000   14.0000000000000000    0.0000000000000000
     0.0000000000000000    0.0000000000000000   14.0000000000000000
   2
C
 6.0 7.0 7.0
 8.0 7.0 7.0
using PAW_GGA, and gamma point, I can not found the local magmom and ground state bond lenth as is previously reported.
Can you plz specify where the error is?
(I also tried optimization witout LORBIT and the static run using RWIGS, with no difference)
Last edited by rudra-b on Wed Oct 21, 2009 8:50 am, edited 1 time in total.
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rudra-b
#2
Post
by rudra-b » Tue Oct 27, 2009 11:53 am
anyone here to reply?
Last edited by rudra-b on Tue Oct 27, 2009 11:53 am, edited 1 time in total.
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jlrch
- Newbie
- Posts: 26
- Joined: Tue Jun 14, 2005 5:18 pm
#3
Post
by jlrch » Fri Jan 08, 2010 2:34 am
Although Cr2 is a very subtle system for the majority of electronic structure codes, VASP gives a reasonable solution at the GGA level, consisting a collinear AFM configuration at the very short distance of 1.5 A and having sizeable local magnetic moments of the order of 1.5 Bohr magnetons at each atom. Concerning your INCAR file, I suggest you to use Normal precision, increasing the plane-wave cutoff energy to 1.5 * ENMAX, reducing EDIFF to 1.0e-6, and increasing SIGMA to something more reasonable like SIGMA=0.1 eV. Be aware that convergence is very slow, so, increasing NELM to 250 and NSW to 50 would be appropriate.
Last edited by
jlrch on Fri Jan 08, 2010 2:34 am, edited 1 time in total.