[Pw_forum] printing wavefunction on real grid

[vtmtrinh at caltech.edu]

Dear Lorenzo,

Thank you for your help. I am still confused (I may be dump :-)).
Yes, I agree that wavefunction at Gamma is real and thus will have a sign
with it. However, |psi|^2 is a positive quantity. If we multiply |psi|^2
by sign(psi) (which is segno in the code), then |psi|^2*sign(psi) will
have a sign of sign(psi).  Why we want to have a sign with |psi|^2?

Best,

Trinh



> On Tue, August 4, 2009 04:20, vtmtrinh at caltech.edu wrote:
>>  I think I can hard code, adding a few lines to print out psi in real
>>  space.
>
> Dear MyTrin,
> You definitely can!
>
>>
>>  There is one part in the code 'local_dos' I don't understand is the
>> case
>>  where ', lsign=true', i.e. k=gamma and iflag=0, write
>> |psi|^2*sign(psi),
>>  why |psi|^2 has to multiply by sign(psi).  I read thru the code at this
>>  part, but I still could not get it.
>
> Maybe I've misunderstood your question, but that's exactly what the option
> lsign is supposed to do. Wavefunctions in Gamma can be defined ti be real,
> hence they have a well defined sign. Although, they can always be
> multiplied by any complex number (-1 included) and still remain perfectly
> good eigenvalues.
>
> cheers
>
> --
> Lorenzo Paulatto
> SISSA  &  DEMOCRITOS (Trieste)
> phone: +39 040 3787 511
> skype: paulatz
> www:   http://people.sissa.it/~paulatto/
>
>
>
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