[Wien] Lapw1 error

[Lyudmila Dobysheva]

Dear Enrico,

So, the APW+lo makes the first density not good, as there appeared the level 
with -3.34 Ry. I have looked in my old calculations (pure phosphorus and 
alloys with phosphorus) and found that I was completely wrong: these 
phosphorus s-electrons should be in the valence band. I mixed them with P2s.
The APW+lo calculation in the first iteration is wrong,  the -0.79 which comes 
from the atomic density estimate is more correct. Now I think that it is just 
opposite to my first guess - too low, in my calculations the valence band 
starts at -0.2 Ry and these P s-electrons should lie there. The wrong 
linearization energy (too low!) gave a ghost at -3.34 Ry. The LAPW scheme has 
apparently a wider interval of energy where linearization works well, and 
does not give the ghost, and the APW+lo fails. 
So, I think that now, if you can calculate with the LAPW scheme, you can 
obtain a convergent calculation in it, and then try to continue with APW+lo. 
And as a test it would be very interesting to make a calculation APW+lo at 
-0.2 Ry or near, and look at the result, please write me the result - my 
settings of the system do not allow me to repeat calculation of your system 
quickly.
By the way, I was using then:
  0.30    3  0      (GLOBAL E-PARAMETER WITH n OTHER CHOICES, global APW/LAPW)
 0   -0.79      0.010 CONT 0
 0    0.30      0.000 CONT 0
 1    0.30      0.000 CONT 1

This is a good observation, I'll remember that sometimes APW+lo and LAPW may 
give such different results at the first stages.

Best regards
  Lyudmila Dobysheva 
------------------------------------------------------------------
Phys.-Techn. Institute of       | Tel.(home):   7 (3412) 442118
Ural Br. of Russian Ac. of Sci. | Tel.(office): 7 (3412) 218988
426001 Izhevsk, ul.Kirova 132   | Fax:          7 (3412) 250614
RUSSIA                          | E-mail: lyu at otf.fti.udmurtia.su
------------------------------------------------------------------
http://fti.udm.ru/ltt/personals/dobysh.htm
------------------------------------------------------------------