[Pw_forum] transition

[Stefano Baroni]

Using Fermi's golden rule + selection rules + common sense

1) Fermi golden rule:

(All: can everybody read the formula above?)
where (cv) are conduction and valence states

2) selection rules tell you which ones of the above matrix elements  
vanish and which don't

3) common sense: in an extended system, many occupied (v) and empty  
(c) states contribute to the sum, so that selection rules are of  
little help, in general. when the spectrum is dominated by localized  
states, an analysis based on symmetry and selection rules is usually  
much more meaningful ...

hope this helps
Stefano B

On Aug 5, 2009, at 7:50 AM, Mansoureh Pashangpour wrote:

> Dear all
> I have perorm GGA+U for a system with trigonally distorted  (D3d)   
> of octahedral symmetry (MO6) (with orbital 3d6).
> using PDOS for this system perdict two transition. How can I find  
> which transion is allowed or forbbiden?
>
> I am looking forward to hearing from you.
>
> Mansoureh Pashangpour
>
> Islamic Azad University
> Science & Reaserch Branch,
> Tehran, Iran.
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> Pw_forum mailing list
> Pw_forum at pwscf.org
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---
Stefano Baroni - SISSA  &  DEMOCRITOS National Simulation Center -  
Trieste
http://stefano.baroni.me [+39] 040 3787 406 (tel) -528 (fax) /  
stefanobaroni (skype)

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de la pensée - Jean Piaget

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