I am attempting to converge parameters for the Na_sv pseudopotential for use in high pressure alloy simulations.
I am doing this using the experimentally determined bcc structure, which is stable at ambient conditions. I am using the following INCAR:
Code: Select all
ENCUT=200
EDIFF=1E-6
ISIFÂ =Â 3
IBRIONÂ =Â 2
NSWÂ =Â 21
ISPINÂ =Â 1
ISMEARÂ =Â 1
SIGMAÂ =Â 0.1
PRECÂ =Â Accurate
ALGOÂ =Â NORMAL
#IALGOÂ =Â 58
LPLANEÂ =Â .TRUE.
PSTRESSÂ =Â 0
NPARÂ =Â 4
LWAVEÂ =Â .FALSE.
LCHARGEÂ =Â .FALSE.
Without exception, the run fails just after the first ionic step, returning the error "Error EDDDAV: Call to ZHEGV failed." Below is a sample of the output:
Code: Select all
 vasp.5.2.11 01Dec10 complexÂ
 POSCAR found type information on POSCAR  Na
 POSCAR found :  1 types and       1 ions
 LDA part: xc-table for Pade appr. of Perdew
 generate k-points for:   10   10   10
 POSCAR, INCAR and KPOINTS ok, starting setup
 FFT: planning ...(           1 )
 WAVECAR not read
 entering main loop
       N       E                     dE             d eps       ncg     rms          rms(c)
DAV:Â Â Â 1Â Â Â Â Â 0.979439119157E+02Â Â Â Â 0.97944E+02Â Â Â -0.18066E+03Â Â Â 776Â Â Â 0.441E+02
DAV:Â Â Â 2Â Â Â Â Â 0.726616855489E+02Â Â Â -0.25282E+02Â Â Â -0.24073E+02Â Â 1184Â Â Â 0.875E+01
DAV:Â Â Â 3Â Â Â Â Â 0.720825152839E+02Â Â Â -0.57917E+00Â Â Â -0.57879E+00Â Â Â 768Â Â Â 0.202E+01
DAV:Â Â Â 4Â Â Â Â Â 0.720748686810E+02Â Â Â -0.76466E-02Â Â Â -0.76466E-02Â Â 1136Â Â Â 0.149E+00
DAV:Â Â Â 5Â Â Â Â Â 0.720748486767E+02Â Â Â -0.20004E-04Â Â Â -0.20004E-04Â Â Â 816Â Â Â 0.555E-02Â Â Â Â 0.576E+01
DAV:Â Â Â 6Â Â Â Â Â 0.131837706740E+03Â Â Â Â 0.59763E+02Â Â Â -0.29583E+02Â Â Â 752Â Â Â 0.998E+01Â Â Â Â 0.235E+01
DAV:Â Â Â 7Â Â Â Â Â 0.135940115374E+03Â Â Â Â 0.41024E+01Â Â Â -0.60289E+00Â Â Â 792Â Â Â 0.261E+01Â Â Â Â 0.109E+01
DAV:Â Â Â 8Â Â Â Â Â 0.135902154588E+03Â Â Â -0.37961E-01Â Â Â -0.12299E+00Â Â Â 800Â Â Â 0.121E+01Â Â Â Â 0.130E+00
DAV:Â Â Â 9Â Â Â Â Â 0.135807686767E+03Â Â Â -0.94468E-01Â Â Â -0.85748E-02Â Â Â 800Â Â Â 0.242E+00Â Â Â Â 0.286E-01
DAV:Â Â 10Â Â Â Â Â 0.135809341779E+03Â Â Â Â 0.16550E-02Â Â Â -0.80973E-03Â Â Â 968Â Â Â 0.693E-01Â Â Â Â 0.261E-02
DAV:Â Â 11Â Â Â Â Â 0.135809240275E+03Â Â Â -0.10150E-03Â Â Â -0.10230E-04Â Â Â 880Â Â Â 0.853E-02Â Â Â Â 0.156E-02
DAV:Â Â 12Â Â Â Â Â 0.135809246248E+03Â Â Â Â 0.59725E-05Â Â Â -0.23990E-05Â Â Â 888Â Â Â 0.411E-02Â Â Â Â 0.290E-03
DAV:Â Â 13Â Â Â Â Â 0.135809247933E+03Â Â Â Â 0.16854E-05Â Â Â -0.75573E-07Â Â Â 552Â Â Â 0.685E-03Â Â Â Â 0.114E-03
DAV:Â Â 14Â Â Â Â Â 0.135809248756E+03Â Â Â Â 0.82234E-06Â Â Â -0.50781E-07Â Â Â 408Â Â Â 0.545E-03
   1 F= 0.13580925E+03 E0= 0.13580964E+03  d E =0.135809E+03
 curvature:   0.00 expect dE= 0.000E+00 dE for cont linesearch  0.000E+00
 trial: gam= 0.00000 g(F)=  0.000E+00 g(S)=  0.236E+05 ort = 0.000E+00 (trialstep = 0.100E+01)
 search vector abs. value=  0.236E+05
 bond charge predicted
       N       E                     dE             d eps       ncg     rms          rms(c)
Error EDDDAV: Call to ZHEGV failed. Returncode =   7 1   8
As you can see, the energies are totally unreasonable for an experimentally stable structure, and they blow up as the electronic steps continue.
I have tried a number of suggestions that I found on the forum, changing IBRION, AMIX, IALGO, and POTIM, all to no avail. I have also varied the ENCUT and PSTRESS with no changes.
Suspecting that the problem was the psuedopotential, I attempted using the Na and Na_pv PAW-PBE PPs in order to see if this changed anything. When I did this (using the same INCAR, KPOINTS, and POSCAR as before), both runs converged easily.
Na PAW-PBE: TOTEN = -1.301915 eV in 4 ionic steps
Na_pv PAW-PBE: TOTEN = -1.689522 eV in 5 ionic steps
Obviously, I would like to use the Na_sv PP because I am going to be looking at very high pressures and I want to include as many core electrons as possible in the calculations.
I am wondering, has anyone else seen this error? And if so, is there anyway to correct it? I should note that the PPs that I am using are dated as follows:
PAW_PBE Na_sv 28Sep2000
PAW_PBE Na_pv 05Jan2001
PAW_PBE Na 08Apr2002
My PI is away at a conference, and thus I don't have access to the ftp server to check if these are the most recent potentials, so I figured I would post here.
Any help would be very much appreciated!
- Josh Taillon