[Wien] Wavefunction above Fermi energy and normalization

Peter Blaha pblaha at theochem.tuwien.ac.at
Mon Dec 4 18:31:50 CET 2017


Your approach seems right.

Use x lapw2 -qtl   to get the partial charges inside the spheres for 
each eigenvalue.

You can compare this with your normalization program for the parts 
inside the sphere.

Am 04.12.2017 um 18:01 schrieb Leandro Salemi:
> Dear Pr. Blaha,
> 
> Thank you for your quick answer. You are totally right with the case.in2 
> file …
> 
> 
> For the wavefunction, that’s how I do :
> 
> 
> For the interstitial, I integrate the product of PW over the whole space 
> and subtract the part from the spheres using a Rayleigh-expansion of a 
> PW in terms of spherical harmonics.
> 
> 
> In the spheres, I compute terms like Alm* Blm \int u_l(r) dot(u)_l(r) 
> r*r dr for the spheres. These coefficients are found in case.almblm and 
> are actually Alm(k) = SUM_G C_G Alm(k+G) (this I got from a previous 
> mailing thread). I have also terms like Alm* Clm \int u_l(r) u_lo__l(r) 
> r*r dr to take into account the APW+lo and LO ! I guess that the Clm’s 
> in case.almclm are also the ones multiplied by their coefficient C_G(LO) 
> (which are not really part of the PW expansion), just like for Alm and 
> Blm. I sum those terms over the different indexes l,m and over the spheres.
> 
> 
> Actually, I follow more less what is presented in the paper of C. 
> Ambrosch-Draxl and J. O. Sofo (Computer Physics Communications 175 
> (2006) 1–14). They computed <Psi_mk| p |Psi_nk> so I of course adapted 
> the formalism to my need.
> 
> 
> Since you said that wavefunctions where all normalized, even above E_F, 
> I must have missed something somewhere … If you see any mistake in what 
> I have written there or have any references, works or source code I 
> should look at, I would be pleased to hear that ! My aim is to extract 
> exactly the wavefunctions. I will then manipulate them.
> 
> 
> Thank you very much,
> 
> 
> Best regards,
> 
> 
> Leandro Salemi
> 
> 
> P.S. : I might have answered in a not-proper way since I had not 
> received the mail (I did not pay attention that my account was disabled 
> for the reception of the mail ...). Sorry for the inconvenience (now it 
> is enabled).
> 
> 
> 
> 
> 
> Peter Blaha 
> <https://www.mail-archive.com/search?l=wien@zeus.theochem.tuwien.ac.at&q=from:%22Peter+Blaha%22> 
> Mon, 04 Dec 2017 06:13:01 -0800 
> <https://www.mail-archive.com/search?l=wien@zeus.theochem.tuwien.ac.at&q=date:20171204>
> 
> 
> Of course all the wave functions are normalized. It comes automatically 
> after solving the generalized eigenvalue problem in lapw1. Without 
> properly normalized wave functions, how should we calculate an electron 
> density which yields the desired number of electrons ??
> 
> Why did you modify the code ?
> It would be much simpler to set NE in case.in2 to a larger number ....
> 
> I don't know how you actually calculated the norm of a wave function, 
> but due to the dual representation, it is not so straightforward.
> 
> On 12/04/2017 02:55 PM, Leandro Salemi wrote:
> 
>     Dear WIEN2K users and developers,
> 
> 
>     I am currently playing with the wavefunctions in WIEN2K in order to
>     compute material-dependent properties. I must then extract them !
> 
> 
>     I managed to extract the relevant quantities (C_nk(G), the coefficents
>     A_lm, B_lm, C_lm and the radial functions) in order to build the
>     wavefunction. When I try to compute the norm of the wavefunction, I find
>     that it is quite well normalized BUT only for states which are below the
>     Fermi energy … For states above, discrepancies arise and I find numbers
>     like 0.8 or 1.3 …
> 
> 
>     To output the A_lm, B_lm of unoccupied states with "x lapw2 -alm", I
>     modified slightly the l2main.F routine. The following has been done :
> 
>     IF(MODUS.EQ.'ALM ') then
> 
>     !LEANDRO INCLUDE EMPTY BANDS (START)
> 
>     NEMAX_SAVE=NEMAX
> 
>     NEMAX=NE
> 
>     !LEANDRO INCLUDE EMPTY BANDS (END)
> 
>     WRITE(24,2055) s_kvec,t_kvec,z_kvec,n,ne,bname
> 
>     write(24,*) jatom,nemin,nemax,' jatom,nemin,nemax'
> 
>     endif
> 
> 
>     where my modification is in between the “!LEANDRO …”. What I did it just
>     saying that the NEMAX (which normally refers to the number of occupied
>     bands) should go up to the highest computed state and thus, can go above
>     the Fermi level.
> 
> 
>     I was wondering that may be, the states are automatically normalized but
>     only for those below the Fermi level. If this is the case, then I can
>     compute the norm and divide by the sqrt. Am I right or am I missing
>     something ? Since the wavefunction is the basic mathematical description
>     of the material, extracting wrong quantities would be quite problematic ...
> 
>     I am of course taking into account the local orbitals in the process !
> 
>     Are the wavefunctions only normalized below E_F ? If yes, do you know in
>     which part the normalization is done ?
> 
> 
>     If anyone has experience with this topic or any suggestion, I would be
>     please to hear ! I have already checked throughout the mailing list and
>     the user guide ...
> 
> 
>     Thank you,
> 
> 
>     Leandro Salemi
> 
> 
> 
> 
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> 
> 
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