[Pw_forum] dynamical matrix units

[Paolo Giannozzi]

What is exactly contained in the dynamical matrices and
in the eigenvectors / eigendisplacement is explained in 
various comments contained in the code where the dynamical
matrix is diagonalized. All quantities are in atomic 
(Ry) units unless otherwise specified.

P.

On Thu, 2014-01-16 at 08:35 +0100, Federico Gallino wrote:
> I took the square of the eigenvalues in Ry units and I divided the dynamical matrix by the
> sqrt of the mass product in the units provided in .dyn file. I didn't modify the
> eigenvectors. I think the problem concerns the unit conversion.
> 
> Thanks,
> 
> Federico
> 
> 
> 
> Dr. Federico Gallino, Ph.D. SAES Getters S.p.A.
> Computational Material Scientist
> Advanced Computing & Software Development
> 
> 
> Viale Italia, 77
> 20020 Lainate - MI - ITALY
> Tel. +39 02 93178316
> Fax +39 02 93178460
> federico_gallino at saes-group.com
> www.saesgetters.com
> 
> 
> 
> From:	Lorenzo Paulatto <lorenzo.paulatto at impmc.upmc.fr>
> To:	PWSCF Forum <pw_forum at pwscf.org>
> Date:	15/01/2014 19.38
> Subject:	Re: [Pw_forum] dynamical matrix units
> Sent by:	pw_forum-bounces at pwscf.org
> 
> 
> 
> On 01/15/2014 07:12 PM, Federico Gallino wrote:
> > Dear All,
> >
> > I refer to a previous topic concerning "units in dynamical matrix files".
> >
> > Checking by hands the diagonalization of the dynamical matrix (after dividing by the
> sqrt
> > of masses) by the normalized eigenvectors (provided in the .dyn output) I get a factor
> of
> > 0.0625 (i.e. 2pi*1.D-2) between the diagonalised matrix and the eigenvalues (Ry units)
> > provided in .dyn output (e.g. see phonon example 1 for C and Si). Could anyone kindly
> > clarify this point?
> 
> Dear Federico,
> you should tell us exactly what you've done if you want us to find what
> you did wrong. Did you take the square root of the eigenvalues?
> 
> 0.0625 can be many things other than 2pi/100...
> 
> best regards
> 
> 
> 
> --
> Dr. Lorenzo Paulatto
> IdR @ IMPMC -- CNRS & Université Paris 6
> phone:+33 (0)1 44275 084 / skype: paulatz
> www:  http://www-int.impmc.upmc.fr/~paulatto/
> mail: 23-24/4é16 Boîte courrier 115, 4 place Jussieu 75252 Paris Cédex 5
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-- 
 Paolo Giannozzi, Dept. Chemistry&Physics&Environment, 
 Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
 Phone +39-0432-558216, fax +39-0432-558222