[Wien] case.inst and spin orbit interaction

[Stefaan Cottenier]

>     i am a new comer and i have some questions here. in the case.inst 
> file, what does the occupation number mean? for Zn it has an Ar 3d10 
> 4s2 configure, but why it can also be discribed as Ne 6 and Ar 3. what 
> do the 3 and 6 mean? 

6 or 3 is the number of lines which follow in that file, divided by 2 
(=number of states, neglecting spin). It takes the relativistic quantum 
number into account, such that p- and d-states are counted in two steps. 
That's why you have 3 states in the 3th row of the periodic table 
(s,p,p), such that Ne+6 states is equivalent to Ar+3 states (the 3 
relevant states in the 4th row are s,d,d).

> and how to split the electrons into spin-up and spin-down?

It doesn't matter too much. Use the command 'instgen' to get a 
distribution which is guaranteed to work, or use an atomic occupation.

>     and the last question is to perform a spin-polarized calculation, 
> is it necessary to add spin-orbit interaction?

No.

Stefaan


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