[Wien] Al-L edge calculation in hexagonal AlN

[Jorissen Kevin]

Hi Pedro,


first of all : "I get an error" isn't terribly descriptive.

Some options that you have include, indeed, changing the core-valence separation (make it *larger* than the 2p-energy, though - -4.7 won't do).  However, whenever you step away from recommended WIEN defaults, you must realize that you're doing an "expert calculation" and it's up to you to verify it's not producing rubbish (there is a reason why WIEN has a core-valence separation).
I've never just hacked the case.inc file, and I can't guarantee that'll do what you want it to do.
You could also try to calculate the spectrum with the OPTIC program.

There is a publication by Cecile Hebert on calculating low energy edges with WIEN, which may be useful for you to read.


Let me know if there are problems,



Kevin Jorissen



Kevin Jorissen
University of Washington
Dept. of Physics
Box 351560
Seattle, WA-98195-1560
U.S.A.

phone  +1 206 543 3904
fax      +1 206 685 0635

e-mail kevin.jorissen at ua.ac.be
web page http://fraangelico.phys.washington.edu/~jorissen



-----Original Message-----
From: wien-bounces at zeus.theochem.tuwien.ac.at on behalf of Pedro M. F. J. Costa
Sent: Mon 7/24/2006 13:37
To: wien at zeus.theochem.tuwien.ac.at
Subject: [Wien] Al-L edge calculation in hexagonal AlN
 
Dear list,

I am trying to simulate the Al-L2,3 egde for a simple structure of 
hexagonal AlN. Despite having calculated the N-K edge correctly, when I 
change the case.innes in order to account for the Al 2p transitions, I get 
an error from the TELNES program. I assume this is because Wien is 
considering that Al 2p are not core states (the energy for the core / 
valence separation is the default, -6 Ry).

After doing the lstart program, the case.outputst reads the following (for 
Al):

Al                                  RHFS
     NUMBER OF ITERATIONS 350
     PRECISON OF ENERGIES 5.00E-07
     WAVEFUNCTION 1.00E-06
     POTENTIAL 1.00E-06
     INTEGRATION WITH 971 POINTS STARTING AT 0.0013/13 AND INCREMENT  0.0126
     ORBITAL      OCCUPATION     TRIAL ENERGIES
       1S                 1.000                      -4.2250000E+01      
       1S                 1.000                      -4.2250000E+01      
       2S                 1.000                      -1.0562500E+01      
       2S                 1.000                       -1.0562500E+01      
       2P*               1.000                       -1.0562500E+01      
       2P*               1.000                      -1.0562500E+01      
       2P                 2.000                      -1.0562500E+01      
       2P                 2.000                      -1.0562500E+01      
       3S                 1.000                      -4.6944444E+00     N
       3S                 1.000                      -4.6944444E+00     N
       3P*               1.000                      -4.6944444E+00     N
       3P*               0.000                      -4.6944444E+00     N
 A RELATIVE ENERGY PRESSION OF 1.00E-08  IS USED IN  50 ATTEMPTS
 IEX= 13     ICUT=  1     IPRAT=  0
  THE PRATT SCHEME IS USED
         953  RADIAL MESH POINTS REACH UP TO   16.1487087483970       A.U.

I would like to ask you what are the steps to get the Al-L edge? Do I have 
to restart the SCF with a new separation energy (-4.7 Ry, possibly) or is 
there a more straightforward path (for instance, changing the case.inc 
file)?

My best regards,

Pedro
-- 
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Pedro Miguel F. J. Costa

Department of Materials Science and Metallurgy
New Museums Site, Pembroke Street
Cambridge, CB2 3QZ, United Kingdom

Tel.(office): +44 (0)1223 334474
Fax: +44 (0)1223 334437
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