# Re: [Wien] Formula full-potential

```Careful, what you said is not completely right, there is a basis although
it is more complete than a limited set of Gaussian functions.```
```
The angular part (potential, wave function etc) is a truncated spherical
harmonic expansion. The radial part of the wavefunction in the spheres is a
rather complex expansion - best to read carefully the user guide & lectures
for exactly what Lapw, APW+lo are.

---
Professor Laurence Marks
Department of Materials Science and Engineering
Northwestern University
http://www.numis.northwestern.edu
Corrosion in 4D http://MURI4D.numis.northwestern.edu
Co-Editor, Acta Cryst A
"Research is to see what everybody else has seen, and to think what nobody
else has thought"
Albert Szent-Gyorgi
On Dec 29, 2015 21:49, "delamora" <delam...@unam.mx> wrote:

> The point about the full potential is that the radial part inside the
> sphere is numerical, you have a net of points going from r=0 to Rmt, so no
> basis is needed as in the Gaussian program where the radial part is formed
> by gaussian functions.
>
>
> ------------------------------
>
> Tuan,
>
>         What that equation means is that you have a full basis for your
> potentials, functions, etc.
>
>         The plane waves outside muffin tin sphere is ok in a region where
> the potential does not vary too much, but it is hopeless near the atomic
> nuclei where the potential varies as 1/r, near a nucleus the atomic like
> functions work well with this kind of potential, so the problem is to match
> both functions both in value and in slope at the muffin tin sphere.
>
>         It is like the step function where you have two plane waves with
> different frequency and you have to match them at the step.
>
>
>         Saludos
>
>
>                     Pablo
>
>
> ------------------------------
> *De:* wien-boun...@zeus.theochem.tuwien.ac.at <
> wien-boun...@zeus.theochem.tuwien.ac.at> en nombre de Tuan Vu <
> kesitinhkhongdu...@gmail.com>
> *Enviado:* martes, 29 de diciembre de 2015 09:22 p. m.
> *Para:* Wien@zeus.theochem.tuwien.ac.at
> *Asunto:* [Wien] Formula full-potential
>
> Dear Pro. F. Tran
>
> Reason do i need details of the potential:
>
> Time is coming for me to protect my PhD dissertation as part of the
> University-supported project.
> One of the key question that I will answer before the dissertation council
> is that how formula 2.10 in the userguide's.pdf is formed.
> The council includes professors from many universities and academies in
> Russia, so I can't avoid that questions because the reliability
> of the calculation package depends on the full-potential, and so does my
> work. With all of my respect, I hope that you can help me
> with this question about the full-potential.
>
> Rest regards
> PhD. Student Tuan Vu
>
```
```_______________________________________________
Wien mailing list
Wien@zeus.theochem.tuwien.ac.at
http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
SEARCH the MAILING-LIST at:
http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
```