[Pw_forum] About Electron-Phonon Coupling matrix element in QE4.2.1

[程迎春]

Dear Prof. Eyvaz,
Thank you for your quick reply.

>>In addition, I guess  " 0.318816E-08  0.318816E-08  0.318816E-08"
>
>>are the elctron-phonon coupling matrix elements.
>
> No, they are frequencies in Ry.
>
I am not sure about they are frequencies.
I checked the output file "'elph. 0.500000.-0.500000. 0.500000'". The
second line is "  0.185711E-05  0.185711E-05  0.811344E-05".
If they are frequencies in Ry, they can be translated to frequencies
in cm^-1, like "0.2038 0.2038 0.8903 cm^-1". The frequencies value are
much smaller than the values in file Al444.freq, as following:
 "            0.500000 -0.500000  0.500000
  149.4236  149.4236  312.5294
"
Therefore, I do not think the values in second line are frequencies.
>>What is unit of elctron-phonon coupling matrix element?
>
> Ry.

If the value in second line are not EPC matrix elements, where can I find them?
>
> Bests,
> Eyvaz.
> -------------------------------------------------------------------
> Prof. Eyvaz Isaev,
> Department of Physics, Chemistry, and Biology (IFM), Linkoping University,
> Sweden
>
> Theoretical Physics Department, Moscow State Institute of Steel & Alloys,
> Russia,
>
> isaev at ifm.liu.se, eyvaz_isaev at yahoo.com
>
>
>
> ----- Original Message ----
> From: 程迎春 <yccheng.nju at gmail.com>
> To: pw_forum at pwscf.org
> Sent: Tue, January 4, 2011 10:24:49 PM
> Subject: [Pw_forum] About Electron-Phonon Coupling matrix element in QE4.2.1
>
> Dear PWscf users,
>
> In example07 in QE4.2.1, one can calculate electron phonon coupling in
> Al. I have a question about the elctron-phonon coupling matrix element
> unit in the ph.x output file. For example, there are some lines in the
> file "elph. 0.000000. 0.000000. 0.000000" as following:
> ==============================================
>           0.000000      0.000000      0.000000    10     3
>  0.318816E-08  0.318816E-08  0.318816E-08
>     Gaussian Broadening:   0.005 Ry, ngauss=   0
>     DOS =  1.338727 states/spin/Ry/Unit Cell at Ef=  8.321708 eV
>     lambda( 1)=  0.0000   gamma=    0.00 GHz
>     lambda( 2)=  0.0000   gamma=    0.00 GHz
>     lambda( 3)=  0.0000   gamma=    0.00 GHz
>     Gaussian Broadening:   0.010 Ry, ngauss=   0
> ......
> ==============================================
> The "0.000000      0.000000      0.000000    " in the top line is the
> q vector. What do the "10" and "3" mean?
> In addition, I guess  " 0.318816E-08  0.318816E-08  0.318816E-08" in
> the second line are the elctron-phonon coupling matrix elements. What
> is unit of elctron-phonon coupling matrix element?
>
> Thank you in advance.
>
> Bests,
> --
> Y. C. Cheng
> Department of Physics
> Nanjing University
> Nanjing 210093
> P. R. China
> Tel: 86-25-83592907
> Email: yccheng.nju at gmail.com
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-- 
Y. C. Cheng
Department of Physics
Nanjing University
Nanjing 210093
P. R. China
Tel: 86-25-83592907
Email: yccheng.nju at gmail.com