The ABINIT Users Mailing List ( CLOSED )

[Masayoshi Mikami <mmikami@rc.m-kagaku.co.jp>]

Dear Whoming,

As I told you in previous personal correspondence,

- please have fully optimized geometry with your pseudoPP calc.
  the lattice constants/internal coordinates should be fully
  optimized with your PPs.
  Your PPs may differ with the PPs adopted there...

- You misunderstand the LO-TOs.
  Eu is like the mode in ab-plane, and A2u mode // c-axis.
  If q // c, Eu mode is TO, and A2u mode is LO.
  If q // ab-plane,  Eu will be splitted into LO+TO, and A2u mode is  
TO.
 (Then, the rest is your homework ... )

The paper says "the optical modes at Gamma are classified into
2A1g + 2 Eg + 2A2u + 2Eu". It never says, "8 IR modes were
reported including 4 Eu and 4 Au modes"  (This is your mental picture !)
Please cite correctly... :-(

Please let me refrain:
"It is only with the heart that one can see rightly; what is  
essential is invisible to the eye."
("On ne voit bien qu'avec le coeur. L'essentiel est invisible pour  
les yeux.")
You might want to consult with chapters on phonon in some textbooks. ;-)
(There is no royal road ... )

Masayoshi

On 2006/05/24, at 17:02, <whoming@sohu.com> wrote:

> Dear Abiniters,
>
> I am a beginer of ABINIT.
>
> I learned ABINIT by re-calculating the work published in PRB 65,  
> 094302 (2002),
>
> in which, 8 IR-active modes were reported including 4 Eu modes and  
> 4 Au modes
>
> as shown in Table. I.
>
>
> But I can just find 4 Eu modes and 2 Au modes from my calculation,  
> for which,
>
> the input file and results are attached.
>
>
> My analysis of output of ANADDB is as following:
>
>
> Mode 1, A2u,acoustic mode,along z-axis;
>
> Mode 2, 3, Eu,acoustic mode, along y, x-axis, respectively;
>
> Mode 4, 5, degenerate,119.3 cm-1, Eg, Raman-active;
>
> Mode 6, 7, having TO(235.7 cm-1)-LO(266.3 cm-1) splitting when E//a,b,
>
> no TO-LO splitting when E//c (235.7), Eu, IR-active;
>
> Mode 8, 269.4 cm-1, A1g, Raman-active;
>
> Mode 9, 315.3 cm-1, A2u, IR-active;
>
> Mode 10, 475.2 cm-1, A2u, IR-active;
>
> Mode 11, 15, having TO(485.2 cm-1)-LO(599.6 cm-1) splitting when E// 
> a,b,
>
> TO(485.2 cm! -1)-LO(587.4 cm-1) when E//c,
>
> Eu, IR-active;
>
> Mode 12, 513.9 cm-1, A1g, Raman-active;
>
> Mode 13, 14, degenerate, 545.4cm-1, Eg, Raman-active.
>
>
> The frequencies is some different from those published due to the  
> different
>
> parameters used during the calculation.
>
>
> Is there anything wrong in my calculation and analysis?
>
> Your kind help and suggestions are greatly appreciated!
>
>
> Yours,
>
> Whoming
>
>
> ??1G??U??????U?U??
> ???????????
> <Y2O2S_gamma.in>
> <anaddb.in>
> <anaddb.files>
> <Y2O2S_gammao_DS3_DDB>
> <Y2O2S_gamma.out>
> <E_along_x_anaddb.out>
> <E_along_z_anaddb.outA>