[Pw_forum] (no subject)

[Stefano Baroni]

Dear YC Cheng,

I am afraid it will take a bit longer to you to understand how to  
calculate infrared and Raman intensities, than just reading the QE  
users' manual. Please, make sure you undrestand first how IR and Raman  
intensities are given in terms of the Born effective charges and  
derivatives of the polarizability tensor, respectively. This  
information is NOT contained in the dynamical matrix. Any standard  
advanced texbook on lattice dynamics would do. You may want to browse  
for references in our RMP paper first: see: S. Baroni et al. Rev. Mod.  
Phys. 73, 515 (2001).

Hope this helps
Stefano Baroni

On Apr 10, 2008, at 4:00 PM, 程迎春 wrote:

> Dear PWscf users:
>         I am trying to test the IR and Raman properties of silicon.  
> I followed the instruction of the user's manual(scf, phonon at  
> gamma, dynmat.x) and got diagonalizing the dynamical matrix. I am  
> shame that I can't understand the dynamical matrix. The matrix is  
> list as follows:
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> ======================================================================
>  q =       0.0000      0.0000      0.0000
>   
> **************************************************************************
>      omega( 1) =       0.000000 [THz] =       0.000005 [cm-1]
>  (  0.000000   0.000000    -0.707107   0.000000     0.000000    
> 0.000000   )
>  (  0.000000   0.000000    -0.707107   0.000000     0.000000    
> 0.000000   )
>      omega( 2) =       0.000000 [THz] =       0.000005 [cm-1]
>  ( -0.707107   0.000000     0.000000   0.000000     0.000000    
> 0.000000   )
>  ( -0.707107   0.000000     0.000000   0.000000     0.000000    
> 0.000000   )
>      omega( 3) =       0.000000 [THz] =       0.000005 [cm-1]
>  (  0.000000   0.000000     0.000000   0.000000    -0.707107    
> 0.000000   )
>  (  0.000000   0.000000     0.000000   0.000000    -0.707107    
> 0.000000   )
>      omega( 4) =      15.294056 [THz] =     510.158172 [cm-1]
>  (  0.000000   0.000000     0.707107   0.000000     0.000000    
> 0.000000   )
>  (  0.000000   0.000000    -0.707107   0.000000     0.000000    
> 0.000000   )
>      omega( 5) =      15.294056 [THz] =     510.158172 [cm-1]
>  (  0.000000   0.000000     0.000000   0.000000    -0.707107    
> 0.000000   )
>  (  0.000000   0.000000     0.000000   0.000000     0.707107    
> 0.000000   )
>      omega( 6) =      15.294056 [THz] =     510.158172 [cm-1]
>  ( -0.707107   0.000000     0.000000   0.000000     0.000000    
> 0.000000   )
>  (  0.707107   0.000000     0.000000   0.000000     0.000000    
> 0.000000   )
>   
> **************************************************************************
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> ======================================================================
> How can I get the IR and Raman mode and the intensity?
> Thanks in advance!
>                                                                       
> Best regards.
>
> -- 
> Y. C. Cheng
> Department of Phyics
> Nanjing University
> Nanjing 210093
> P. R. China
> Tel: 86-25-83592907
> Email: yccheng.nju at gmail.com
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---
Stefano Baroni - SISSA  &  DEMOCRITOS National Simulation Center -  
Trieste
[+39] 040 3787 406 (tel) -528 (fax) / stefanobaroni (skype)

La morale est une logique de l'action comme la logique est une morale  
de la pensée - Jean Piaget

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