[Pw_forum] second energy parameter setting in RRKJ USPP

[Prasenjit Ghosh]

Dear Stefano,

Thanks for the nice explanation.
Can you please suggest some "old" quantum mechanics books or some other
reading materials where they deal with such issues?

With regards,
Prasenjit.

2008/8/11 Stefano Baroni <baroni at sissa.it>

> Dear Wenmei:
>
> besides the very sound suggestion by Hande, I would also recommend
> that you take a glance at any (possibly, old) textbook in elementary
> quantum mechanics. Why old? Because modern texts often given
> elementary stuff for granted, which usually it is not.
>
> Coming to the specific issue that you raise. The number of nodes in
> the solution of a 1D Schroedinger equation depends on the energy
> parameter. The lower the energy, the fewer the nodes.  Of course, for
> an arbitrary energy parameter the resulting wavefunction is not
> normalizable, that is why it has to be discarded, but for very
> special, discrete, values, and energy is quantized. It is interesting
> to understand "intuitively" how quantization of energy comes about. As
> you rise the energy from any given value, the outer node moves out
> furthhr and futher from the origin, but the number of nodes stays
> constant if you do not change the energy too much. If the energy is
> raised too much, a further node will appear. For some critical value
> of the energy, the "extra" node will be at infinity: that's when an
> energy eigenvalue is crossed.
>
> I do not expect that, if you have never heard about similar
> arguments,  you will understand mine, which have been stated rather
> sloppily. Actually, if you decide to study this matter in a serious
> book, your ability to understand my "sloppy arguments" will be a check
> of your actual understanding of the serious arguments expounded in the
> book.
>
> Hope this helps, a bit
> Stefano
>
> On Aug 11, 2008, at 6:36 PM, Hande Ustunel wrote:
>
> > Dear Wenmei,
> >
> > I usually look at the output of the all-electron calculation and
> > choose an
> > energy close to the ae orbital energy. Once I manage to generate the
> > pseudopotential I go as far away as possible from that reference
> > without
> > upsetting the code.
> >
> > Hope this helps...
> > Hande
> >
> > On Tue, 12 Aug 2008, [gb2312] 明文美 wrote:
> >
> >>
> >> Dear all:
> >>
> >>      I want to generate my own RRKJ type ultrasoft pseudopotential
> >> with atomic code in PWSCF,
> >> I encountered a very confusing situation:
> >>
> >>  when I chose -0.20Ry as the second energy used to pseudize the 5s
> >> orbit, the ld1.x always complains :
> >> =================================================
> >>    from gener_pseudo : error #         1     too many nodes
> >> =================================================
> >>   however if I change the energy to be -0.50Ry, the corresponding
> >> complain disappeared.
> >>
> >> How should I choose these energy parameters to generate a good
> >> pseudopotential and how should I have a
> >> correct understanding of these parameters?
> >>
> >> Thanks very much .
> >>
> >> Wenmei
> >>
> >> My &inputp file is also listed as :
> >>
> >> 64D  3  2   10   0.00  1.00   2.004D  3  2   0    -0.20 1.00
> >> 2.005S  1  0   2    0.00  2.00   2.505S  1  0   0    -0.50  2.00
> >> 2.505P  2  1   3    0.00  2.66   2.985P  2  1   0    -0.20  2.66
> >> 2.98
> >>
> >>
> >>
> >>
> >>
> >> _________________________________________________________________
> >> 快来看看这些猫咪有多逗，爆笑！
> >>
> http://cnweb.search.live.com/video/results.aspx?q=%E5%8F%AF%E7%88%B1%E7%8C%AB%E5%92%AA&Form=MEVHAA
> >
> > --
> > Hande Toffoli
> > Department of Physics
> > Office 439
> > Middle East Technical University
> > Ankara 06531, Turkey
> > Tel : +90 312 210 3264
> > http://www.physics.metu.edu.tr/~hande<http://www.physics.metu.edu.tr/%7Ehande>
> >
> > _______________________________________________
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> > Pw_forum at pwscf.org
> > http://www.democritos.it/mailman/listinfo/pw_forum
>
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-- 
PRASENJIT GHOSH,
POST-DOC,
ROOM NO: 265, MAIN BUILDING,
CM SECTION, ICTP,
STRADA COSTERIA 11,
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ITALY
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