[Pw_forum] failure with NCPP

Eric J. Walter ejwalt at wm.edu
Mon Jul 20 18:45:00 CEST 2009


Dear Haiping and Luke,

The kink is due to the GGA functional and it occurs in both TM and Opt 
forms of the psp (and in other psp generation codes as well using similar
parameters).  This does not result in a large cut-off energy, which  
Haiping may have known since he probably checked the energy
convergence w.r.t. cut-off energy. (?)

The psp can be regenerated with the directive to smooth the XC potential 
before a certain radius.  This is done by adding either a positive or
negative (for two different smoothing methods) after "gga" in the XC 
block.  If I add -0.02, I get a very nice looking potential.

I think that any further opium questions/discussions should be sent to 
the opium mailing list:  opium-talk at sourceforge.net

Hope this helps,

Eric



lan haiping wrote:
> Dear Luke,
>
> I tested this pseudopotential for Zinc  bulk (Hex), and got   well 
> comparable lattice constants 2.65 , 4.97 \AA,  and the bulk module is 
> 74.2 KBar by fitting Murnaghan Equation (Energy cutoff was set to 50 
> Hartree) .   Opium's test also gives small differences for eigenvalues 
> from different configurations.  
>
> Is there any way to improve the quality or remove the kink you 
> mentioned ?  I forgot to check ionic potential, and just found it 
> indeed has a large kink .
>
> thanks.
>
> regards,
> On Mon, Jul 20, 2009 at 10:38 PM, Luke Shulenburger 
> <lshulenburger at ciw.edu <mailto:lshulenburger at ciw.edu>> wrote:
>
>     Hello,
>
>     I took a quick look at these pseudopotentials.  The first thing I
>     found is that the problem seems to be related to  the augmentation
>     functions.  I removed the second and third line after KBdesign in the
>     Zn input and the potential loads into pwscf without issue.  I haven't
>     used augmentation functions much, so I'm not sure quite what the
>     problem is.  I know Eric Walter looks at this list from time to time,
>     perhaps he could comment on the reason for this.  The other thing is
>     that the the output from opium for the Zn pseudopotential looks
>     somewhat strange.  As an example, the plots of the ionic potential are
>     not very smooth at all and there are large kinks near the origin which
>     will likely result an a very high plane wave cutoff being necessary to
>     get converged results.  Has this potential been tested?
>
>     Sincerely,
>     Luke Shulenburger
>     (lshulenburger at ciw.edu <mailto:lshulenburger at ciw.edu>)
>     Geophysical Laboratory
>     Carnegie Institution of Washington
>     5251 Broad Branch Rd. NW
>     Washington, DC 20015
>
>
>     On Mon, Jul 20, 2009 at 8:28 AM, lan haiping<lanhaiping at gmail.com
>     <mailto:lanhaiping at gmail.com>> wrote:
>     > Dear Paolo,
>     > Thanks .
>     > I then check input settings for opium ,  and find the
>     wavefunctions are
>     > already arranged by increasing 'l'.
>     >  The setting for Zn  pseudopotential  is following:
>     > "
>     > [Atom]
>     > Zn
>     > 8                   # norb: number of orbitals
>     > 100  2.00  -        # nlm occ eigen(- means auto-generate)
>     > 200  2.00  -
>     > 210  6.00  -
>     > 300  2.00  -
>     > 310  6.00  -
>     > 400  1.50  -
>     > 410  0.00  -
>     > 320  10.00  -
>     >
>     > [Pseudo]
>     > 3  1.87 1.85 1.97
>     > opt
>     >
>     > [Optinfo]
>     > 7.07 10
>     > 7.07 10
>     > 7.07 10
>     > [XC]
>     > gga               # lda[PZ] or gga[PBE]
>     >
>     > [KBdesign]
>     > 0                 # local orb
>     > 1                # number of aug. operators
>     > au 0.1 1.60 -3.05  # unit(gp or au)  left  right  height(Ry)
>     > [Loginfo]
>     > 0
>     > 2.0 -4.0 4.0
>     > "
>     > and for O is
>     > "
>     > [Atom]
>     > O
>     > 3
>     > 100   2.00   -
>     > 200   2.00   -
>     > 210   4.00   -
>     > [Pseudo]
>     > 2  1.34 1.53
>     > opt
>     > [Optinfo]
>     > 7.07  10
>     > 7.07  10
>     > conmax
>     > [XC]
>     > gga
>     > "
>     >
>     > I donot know why these PP cannot be read by pw.x .
>     > By the way, is there any simple method to use  opium's settings  in
>     > ld1.x   ?
>     >
>     >
>     > Regards,
>     >
>     > Hai-Ping
>     >
>     >
>     > On Mon, Jul 20, 2009 at 4:49 PM, Paolo Giannozzi
>     <giannozz at democritos.it <mailto:giannozz at democritos.it>>
>     > wrote:
>     >>
>     >> lan haiping wrote:
>     >>
>     >> > I wonder  whether QE still support NCPP format
>     >>
>     >> it does, otherwise it would have issued a different message
>     >>
>     >> > or other special consideration needs to take into for opium's
>     pp ?
>     >>
>     >> atomic wavefunctions should be in order of increasing l.
>     >> Not sure why this is needed and whethere it is really needed.
>     >>
>     >> P.
>     >> --
>     >> Paolo Giannozzi, Democritos and University of Udine, Italy
>     >> _______________________________________________
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>     >> http://www.democritos.it/mailman/listinfo/pw_forum
>     >
>     >
>     >
>     > --
>     > Hai-Ping Lan
>     > Department of Electronics ,
>     > Peking University , Bejing, 100871
>     > lanhaiping at gmail.com <mailto:lanhaiping at gmail.com>,
>     hplan at pku.edu.cn <mailto:hplan at pku.edu.cn>
>     >
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>
>
>
> -- 
> Hai-Ping Lan
> Department of Electronics ,
> Peking University , Bejing, 100871
> lanhaiping at gmail.com <mailto:lanhaiping at gmail.com>, hplan at pku.edu.cn 
> <mailto:hplan at pku.edu.cn>
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