The ABINIT Users Mailing List ( CLOSED )

[Chol-Jun Yu <yucj@ghi.rwth-aachen.de>]

Hello,

well, you should increase the ecut (in my experience about B2 NiAl, ecut 
should be at least 50 ha = 1360 eV in the case of norm-conserving PP).

Maybe you did not use primitive unit cell which includes two atoms.

Best,
Choljun

Stephen.Hocker@mpa.uni-stuttgart.de wrote:
> Dear Abinit users,
>
> I'm trying to calculate the elastic constants of B2 NiAl using the serial
> version of Abinit 5.4.4, unfortunately I didn't obtain any results yet. Some
> values for the parameters in my infile must be wrong, but I have no idea
> which ones I should change.
> The calculation starting from an input file like the one for Al which is 
> given in the elastic tutorial stopped with the message:
> kpgsph : BUG -
>   The variables ikg, mkmem, and mpw  must satisfy ikg<=(mkmem-1)*mpw,
>   while the arguments of the routine are
>   ikg =    3060, mkmem =      20, mpw =     159
>   Probable cause: Known error in invars1 for parallel spin-polarized case.
>   Temporary solution: Change the number of parallel processes.
>   Action : contact ABINIT group.
>
> Therefore I decided to determine the elastic constants by calculation of the
> energies of strained samples. In these calculations the total energy should 
> increase parabolically with increasing strain. But it doesn't. Depending on 
> the parameters it usually increases somehow, but the curve is never a 
> parabola. In some cases it even decreases a little.  
> These are the parameters I already tried:
> ecut (280...480 eV)
> ngkpt (2 2 2...10 10 10)
> nband/fband 65/0.0d0 
> occopt 3...4
> tsmear 0.03...0.07
> I tried with different pseudopotentials (Troullier-Martins) as well, namely
> 13al.pspnc, 28ni.pspnc / 13-Al.LDA.fhi, 28-Ni.LDA.fhi,  13-Al.GGA.fhi,
> 28-Ni.GGA.fhi.
>
> What else could be wrong? Thanks for any help.
> Best regards,
> Stephen
>
> This is one of my infiles: 
> acell 5.7970482729504687 5.767560060000 5.767560060000 angstrom
> ecut 480 eV
> ionmov 0 
> ixc 1 
> kptopt 1 
> natom 16
> ngkpt 10 10 10 
> nstep 15 
> ntypat 2 
> nband 65
> occopt 4 
> tsmear 0.03
> toldfe 0.005 eV
> chkprim 0
> znucl 13 28
> typat 
> 1
> 1
> 1
> 1
> 1
> 1
> 1
> 1
> 2
> 2
> 2
> 2
> 2
> 2
> 2
> 2
> xangst 0.000000 0.000000 0.000000
> 0.000000 0.000000 2.883780
> 0.000000 2.883780 0.000000
> 0.000000 2.883780 2.883780
> 2.898524 0.000000 0.000000
> 2.898524 0.000000 2.883780
> 2.898524 2.883780 0.000000
> 2.898524 2.883780 2.883780
> 1.449262 1.441890 1.441890
> 1.449262 1.441890 4.325670
> 1.449262 4.325670 1.441890
> 1.449262 4.325670 4.325670
> 4.347786 1.441890 1.441890
> 4.347786 1.441890 4.325670
> 4.347786 4.325670 1.441890
> 4.347786 4.325670 4.325670


--
Chol-Jun Yu
Computational Materials Engineering (CME)
Institute of Minerals Engineering (GHI)
Center for Computational Engineering Science (CCES)
RWTH Aachen University (RWTH)
Jülich-Aachen Research Alliance (JARA)
Mauerstr. 5, D-52056 Aachen
Tel.: +49-241-8094989 Fax: +49-241-80695097