[Pw_forum] help

leila messad messadleila at yahoo.fr
Wed Jan 11 12:25:22 CET 2012


i am a new user of quantum espresso
i want to study the phonon dispersion of CoPt (tetragonal

cell (c/a=,95)) structure,with 2 atoms having position 0 0 0 , .5.5.5, 


 how can  find the phonon dispersion and vibrational
energy


because i used the ph.x code to calculate the phonon dispersion at q = 0,

i found six branches with:
     omega( 1) =      -0.316230 [THz] =     -10.548352 [cm-1]
     omega( 2) =       1.110175 [THz] =      37.031704 [cm-1]
     omega( 3) =       1.110175 [THz] =      37.031704 [cm-1]
     omega( 4) =       4.301130 [THz] =     143.471216 [cm-1]
     omega( 5) =       4.301130 [THz] =     143.471216 [cm-1]
     omega( 6) =       5.145640 [THz] =     171.641221 [cm-1]
is it correct?

thanks


for phonon calculation what should my position of atoms so that i can get
the vibrational energy from linear response theory
if i used the above i am getting 12 phonon branches  is it correct?
suggestions may help to know more about it
thanks


--- En date de : Mer 11.1.12, pw_forum-request at pwscf.org <pw_forum-request at pwscf.org> a écrit :

De: pw_forum-request at pwscf.org <pw_forum-request at pwscf.org>
Objet: Pw_forum Digest, Vol 55, Issue 18
À: pw_forum at pwscf.org
Date: Mercredi 11 janvier 2012, 6h13

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Today's Topics:

   1. Re: MD calculation, and Conjugate Gradient? (Abdeslam Houari)
   2. Re: VCA (was: no subject) (Paolo Giannozzi)
   3. Re: MD calculation, and Conjugate Gradient? (Paolo Giannozzi)
   4. Re: charge-density.dat file missing after SCF    calculations
      (Paolo Giannozzi)
   5. sn calculation (bhabya sahoo)
   6. Re: VCA (was: no subject) (Ali Tavana)
   7. Fwd: sn calculation (bhabya sahoo)


----------------------------------------------------------------------

Message: 1
Date: Tue, 10 Jan 2012 16:48:30 +0000 (GMT)
From: Abdeslam Houari <habdslam at yahoo.fr>
Subject: Re: [Pw_forum] MD calculation, and Conjugate Gradient?
To: PWSCF Forum <pw_forum at pwscf.org>
Message-ID:
    <1326214110.91893.YahooMailClassic at web27402.mail.ukl.yahoo.com>
Content-Type: text/plain; charset="iso-8859-1"

I understand ... may be I was deceived by another ab inito code (without citing the name) where they specify "conjugate gradient" as a type of run of the molecular dynamics !!!? 
Thanks a lot Y.P

--- En date de?: Mar 10.1.12, Yunpeng Wang <yunpengwang at live.com> a ?crit?:

De: Yunpeng Wang <yunpengwang at live.com>
Objet: Re: [Pw_forum] MD calculation, and Conjugate Gradient?
?: pw_forum at pwscf.org
Date: Mardi 10 janvier 2012, 15h37





Meaning of MD is to follow the Newton equation with the total energy (kinetic energy plus interaction energy). However, the CG method is used to find the minimum interaction energy and kinetic energy makes no sense in CG method.

YP

Date: Tue, 10 Jan 2012 14:32:52 +0000
From: habdslam at yahoo.fr
To: pw_forum at pwscf.org
Subject: [Pw_forum] MD calculation, and Conjugate Gradient?

Dear QE developers and users; 
I'm using QE-4.3.2 and I wanna do Molecular Dynamics calculations, with Conjugate Gradient scheme... When looking to PWscf documentation (INPUT_PW) I find only the "verlet" and "langevin" algorithm for "calculation=md" !! I wanna be sure if the conjugate gradient is included (possible) or not? 

Thanks in advance
Best regards? ? 

=======================================
Abdesalem HOUARI
-------------------------------------------------------------------------------------------
Department of physics, Theoretical Physics Laboratory
University of Bejaia-06000. Algeria.
E-mail:?abdeslam.houari at univ-bejaia.dz & habdslam at yahoo.fr
https://sites.google.com/site/houariabdeslam/homepage
Phone: +213 34 21 53 04
Fax: +213 34 21 59 86
Cell phone: +213 551 36 29 01 (emergency only !!)
========================================

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Message: 2
Date: Tue, 10 Jan 2012 18:31:52 +0100
From: Paolo Giannozzi <giannozz at democritos.it>
Subject: Re: [Pw_forum] VCA (was: no subject)
To: PWSCF Forum <pw_forum at pwscf.org>
Message-ID: <0EF6524A-68CC-468A-8D8A-B25CF4473734 at democritos.it>
Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed


On Jan 10, 2012, at 8:22 , Ali Tavana wrote:

> I am looking for the reference paper for the VCA implementation
> in QE (i.e. virtual.x code).

there is no such paper. This is the VCA implementation in QE,
if I remember correctly:
    V^{(vca)} = V_{loc)^{(vca)} + V_{nl}^{(vca)}
where
    V_{loc)^{(vca)} = x V_{loc}^{(1)} + (1-x) V_{loc}^{(2)}
and
    V_{nl)^{(vca)} = \sum_{ij} |\beta^{(1)}_i> x D^{(1)}_{ij} <\beta^ 
{(1)}_j|
                      +  \sum_{ij} |\beta^{(2)}_i> (1-x) D^{(2)}_{ij}  
<\beta^{(2)}_j|
where
  V_{loc}^{(n)}(r) is the local part of PP n ;
  \beta^{{n)}_i(r) are the projectors for PP n ;
  D^{(n))_{ij} are the (bare) components of matrix D for PP n

P.
---
Paolo Giannozzi, Dept of Chemistry&Physics&Environment,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222






------------------------------

Message: 3
Date: Tue, 10 Jan 2012 18:49:33 +0100
From: Paolo Giannozzi <giannozz at democritos.it>
Subject: Re: [Pw_forum] MD calculation, and Conjugate Gradient?
To: PWSCF Forum <pw_forum at pwscf.org>
Message-ID: <637B6B27-1302-4B0E-833D-031B397AE9F6 at democritos.it>
Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed


On Jan 10, 2012, at 17:48 , Abdeslam Houari wrote:

> [...] they specify "conjugate gradient" as a type of run of the  
> molecular dynamics !!!

you can perform molecular dynamics, using a conjugate-gradient  
algorithm to
solve the electronic problem at each step. The CP code can also do  
this, by
the way, in addition to Car-Parrinello dynamics (which is a different  
kind of
dynamics)

P.
---
Paolo Giannozzi, Dept of Chemistry&Physics&Environment,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222






------------------------------

Message: 4
Date: Tue, 10 Jan 2012 18:55:13 +0100
From: Paolo Giannozzi <giannozz at democritos.it>
Subject: Re: [Pw_forum] charge-density.dat file missing after SCF
    calculations
To: PWSCF Forum <pw_forum at pwscf.org>
Message-ID: <DFABCDF6-69ED-4D1B-AB64-071010E2183F at democritos.it>
Content-Type: text/plain; charset=US-ASCII; format=flowed


On Jan 10, 2012, at 14:38 , Kiss, Ioan wrote:

> However, after the NSCF calculation is finished there is no
> charge-density.dat file present in the prefix.save directory


this sounds hard to believe to me. The non-scf calculation
doesn't destroy the charge density file.

P.
---
Paolo Giannozzi, Dept of Chemistry&Physics&Environment,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222






------------------------------

Message: 5
Date: Wed, 11 Jan 2012 01:22:15 +0530
From: bhabya sahoo <bdslipun at gmail.com>
Subject: [Pw_forum] sn calculation
To: PWSCF Forum <pw_forum at pwscf.org>
Message-ID:
    <CAJVAAvBWmMK_0-o-xdip_n0xaReLggghwevJgWSvT72G4p20SQ at mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"

i am a new user of quantum espresso
i want study the alpha-beta transition of tin(Sn)
i found the phonon dispersion of alpha(diamond) structure
but for beta structure how can  find the phonon dispersion and vibrational
energy


because i calculated the static calculation of beta tin having tetragonal
cell (c/a=,546)
and 4 atoms having position 0 0 0 , .5.5.5, 0.5.75,.5 0 .25


for phonon calculation what should my position of atoms so that i can get
the vibrational energy from linear response theory
if i used the above i am getting 12 phonon branches  is it correct?
suggestions may help to know more about it
thanks














bd sahoo
barc
mumbai
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Message: 6
Date: Wed, 11 Jan 2012 06:28:58 +0330
From: Ali Tavana <tavana.ali at gmail.com>
Subject: Re: [Pw_forum] VCA (was: no subject)
To: PWSCF Forum <pw_forum at pwscf.org>
Message-ID:
    <CALvVrfDGizFEx-mcz=GQ+Xx1-fSBBVPAd+mDyUunf-XLL66s=Q at mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"

Thank you very much.


Ali Tavana, PhD.,
Assistant Prof.,
Department of Physics,
University of Mohaghegh Ardabili,
Ardabil, Iran.

TEL: +98 451 5512081 (2430)
FAX: +98 451 5514701
EMAIL: a_tavana at alum.sharif.edu, tavana at uma.ac.ir




On Tue, Jan 10, 2012 at 9:01 PM, Paolo Giannozzi <giannozz at democritos.it>wrote:

>
> On Jan 10, 2012, at 8:22 , Ali Tavana wrote:
>
> > I am looking for the reference paper for the VCA implementation
> > in QE (i.e. virtual.x code).
>
> there is no such paper. This is the VCA implementation in QE,
> if I remember correctly:
>    V^{(vca)} = V_{loc)^{(vca)} + V_{nl}^{(vca)}
> where
>    V_{loc)^{(vca)} = x V_{loc}^{(1)} + (1-x) V_{loc}^{(2)}
> and
>    V_{nl)^{(vca)} = \sum_{ij} |\beta^{(1)}_i> x D^{(1)}_{ij} <\beta^
> {(1)}_j|
>                      +  \sum_{ij} |\beta^{(2)}_i> (1-x) D^{(2)}_{ij}
> <\beta^{(2)}_j|
> where
>  V_{loc}^{(n)}(r) is the local part of PP n ;
>  \beta^{{n)}_i(r) are the projectors for PP n ;
>  D^{(n))_{ij} are the (bare) components of matrix D for PP n
>
> P.
> ---
> Paolo Giannozzi, Dept of Chemistry&Physics&Environment,
> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
> Phone +39-0432-558216, fax +39-0432-558222
>
>
>
>
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum
>
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Message: 7
Date: Tue, 10 Jan 2012 21:13:40 -0800
From: bhabya sahoo <bdslipun at gmail.com>
Subject: [Pw_forum] Fwd: sn calculation
To: PWSCF Forum <pw_forum at pwscf.org>
Message-ID:
    <CAJVAAvBmeW3MvkfrZ+5B6H8RxDH-Xg7RuKrd0Pt8JKNWoHFm0A at mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"

---------- Forwarded message ----------
From: bhabya sahoo <bdslipun at gmail.com>
Date: Tue, Jan 10, 2012 at 11:52 AM
Subject: sn calculation
To: PWSCF Forum <pw_forum at pwscf.org>


i am a new user of quantum espresso
i want study the alpha-beta transition of tin(Sn)
i found the phonon dispersion of alpha(diamond) structure
but for beta structure how can  find the phonon dispersion and vibrational
energy


because i calculated the static calculation of beta tin having tetragonal
cell (c/a=,546)
and 4 atoms having position 0 0 0 , .5.5.5, 0.5.75,.5 0 .25


for phonon calculation what should my position of atoms so that i can get
the vibrational energy from linear response theory
if i used the above i am getting 12 phonon branches  is it correct?
suggestions may help to know more about it
thanks














bd sahoo
barc
mumbai
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