[Wien] about case.scfm results

[Lyudmila Dobysheva]

On Friday 19 August 2005 20:07, Souraya GOUMRI-SAID wrote:
> What is the meaning of : SPINDENSITIES AT THE NUCLEUS (THOMSON) for
> VALENCE, SEMI-CORE, CORE,TOTAL etc.

       DENSITY AT NUCLEUS
        JATOM    VALENCE       SEMI-CORE            CORE           TOTAL
:RUP001:   1        3.393254        0.000000     7607.882913     7611.276167
:RDN001:   1        3.826265        0.000000     7607.173181     7610.999445

This is a density of spin up and down electrons in a point near the center of 
the nucleus, namely, in a point specified in the struct file R0 (the first 
point of the region R0-RMT, where 781 points are considered):
Fe         NPT=  781  R0=0.00005000 RMT=    2.3000   Z: 26.0
This value may be used in order to estimate isomer shifts in a row of 
compounds of the same type.
VALENCE and CORE are the contributions from the densities of the corresponding 
electrons. 

       SPINDENSITIES AT THE NUCLEUS (THOMSON) FOR ATOM  1
          VALENCE       SEMI-CORE            CORE           TOTAL
             2.954163        0.000000     6479.701804     6482.655967
             3.323652        0.000000     6479.097213     6482.420865
:HFF001: HFF:-193.723           0.000         316.987         123.264 (KGAUSS)

This is a density integrated over a sphere around the nucleus (the integration 
comes from relativity effects, the nucleus becomes not a point). Its radius - 
THOMSON radius - depends on the charge of a nucleus. Again, you see spin up 
and down parts, the difference gives a proportion to the HFF - hyperfine 
field.

> are these results dependent in numerical parameters related to the method :
> kpoint, RMt,

The dependence on Nkpoint and RMT is a usual convergence dependence, they 
should be chosen good enough. The first value DENSITY AT NUCLEUS is very 
dependent on the R0 from the physical reasons, so you can not obtain a 
certain value of isomer shift in principle. The second one, as an integrated 
value, does not depend on it. Both values depends on the approximation of the 
exchange-correlation potential (LDA, GGA), but in a typical way.

> Secondly at the end of the file, we find the data about forces in Ry for
> any elements considered in the simulated system. 

It is used in order to find the equilibrium of the system, sometimes the known 
positions of the atoms, that we put in a structure file, are not good, and 
you may want to find their better position.

Best regards
  Lyudmila Dobysheva 
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