[Pw_forum] radius distribution function (Pw_forum Digest, Vol 24, Issue 49)

Gabriele Sclauzero sclauzer at sissa.it
Tue Jun 23 16:44:02 CEST 2009


I don't have the code at hand in this moment. It was not 'my' code anyway. If I remember 
well I used that from Frenkel and Smit's book. You can download it from this website

http://molsim.chem.uva.nl/frenkel_smit/README.html

for instance in this case study

http://molsim.chem.uva.nl/frenkel_smit/Exercise_10/index.html

The subroutine which accumulate statistics for the radial distribution function should be 
   sample_gyra.f.

GS

JAY wrote:
> Dear Gabriele
>  
> Thank you for your reply. I am a new learner of fortran 90, so it is 
> much more helpful, if you send me your source code. I will make some 
> modification where necessary. Could you please send me a copy of that 
> fortran code?
> 
> On Tue, Jun 23, 2009 at 6:08 PM, <pw_forum-request at pwscf.org 
> <mailto:pw_forum-request at pwscf.org>> wrote:
> 
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>     Today's Topics:
> 
>       1. Re: radius distribution function (Gabriele Sclauzero)
>       2. Re: Separating Raman modes (alexandra.carvalho at epfl.ch
>     <mailto:alexandra.carvalho at epfl.ch>)
>       3. Zero of the electrostatic potential ? (Vladan Stevanovic)
>       4. Re: Zero of the electrostatic potential ? (Gabriele Sclauzero)
>       5. Re: Zero of the electrostatic potential ? (Lorenzo Paulatto)
>       6. Re: Zero of the electrostatic potential ? (Stefano de Gironcoli)
>       7. Re: Zero of the electrostatic potential ? (Paolo Giannozzi)
> 
> 
>     ----------------------------------------------------------------------
> 
>     Message: 1
>     Date: Tue, 23 Jun 2009 09:03:49 +0200
>     From: Gabriele Sclauzero <sclauzer at sissa.it <mailto:sclauzer at sissa.it>>
>     Subject: Re: [Pw_forum] radius distribution function
>     To: PWSCF Forum <pw_forum at pwscf.org <mailto:pw_forum at pwscf.org>>
>     Message-ID: <4A407E55.5070704 at sissa.it
>     <mailto:4A407E55.5070704 at sissa.it>>
>     Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> 
>     Dear Jay,
> 
>     JAY wrote:
>      > Dear users
>      >
>      > Could anybody send me the fortran code for calculating radius
>      > distribution function? I would like to analyze the MD results.
>     Many thanks.
> 
>     If you meant "radial distribution function", I think you can find
>     good recipes on how to
>     write it on any molecular dynamics textbook, from the old classics
>     by Frenkel-Smit or
>     Allen-Tildesley to the modern ones. If you are really in trouble I
>     can send you a fortran
>     code from a course on atomistic simulations I followed at University
>     (at the moment I'm
>     not doing molecular dynamics calculations), but I think there are
>     many people doing much
>     more sophisticated things on this forum. They could help you better
>     than me.
> 
>     GS
> 
> 
> 
>      >
>      > --
>      > Sincerely
>      >
>      > Jay
>      >
>      >
>      > ==============================================
>      > cn:       Li, Jiaye
>      > en:       Jay Y. Lee
>      >
>      > M.S. in designing and developing novel materials
>      >
>      > Research experience:
>      > *ALD precursor. ie. Metal complexes
>      > *Surface modification. ie. Indium tin oxide, SiO2
>      > *Gas storage and adsorption. ie. Ionic Liquids
>      >
>      > Skills:
>      > *ab-initial method, DFT simulation and Force Field simulation
>      >
>      > Please contact me at:
>      > 1. jameslipd at gmail.com <mailto:jameslipd at gmail.com>
>     <mailto:jameslipd at gmail.com <mailto:jameslipd at gmail.com>>  or
>      > 2. jameslibd at gmail.com <mailto:jameslibd at gmail.com>
>     <mailto:jameslibd at gmail.com <mailto:jameslibd at gmail.com>>
>      >
>      > ==============================================
>      >
>      >
>      >
>     ------------------------------------------------------------------------
>      >
>      > _______________________________________________
>      > Pw_forum mailing list
>      > Pw_forum at pwscf.org <mailto:Pw_forum at pwscf.org>
>      > http://www.democritos.it/mailman/listinfo/pw_forum
> 
>     --
> 
> 
>     o ------------------------------------------------ o
>     | Gabriele Sclauzero, PhD Student                  |
>     | c/o:   SISSA & CNR-INFM Democritos,              |
>     |        via Beirut 2-4, 34014 Trieste (Italy)     |
>     | email: sclauzer at sissa.it <mailto:sclauzer at sissa.it>              
>               |
>     | phone: +39 040 3787 511                          |
>     | skype: gurlonotturno                             |
>     o ------------------------------------------------ o
> 
> 
>     ------------------------------
> 
>     Message: 2
>     Date: Tue, 23 Jun 2009 10:31:06 +0200
>     From: alexandra.carvalho at epfl.ch <mailto:alexandra.carvalho at epfl.ch>
>     Subject: Re: [Pw_forum] Separating Raman modes
>     To: PWSCF Forum <pw_forum at pwscf.org <mailto:pw_forum at pwscf.org>>
>     Message-ID: <20090623103106.17671jzible9ehu2 at webmail.epfl.ch
>     <mailto:20090623103106.17671jzible9ehu2 at webmail.epfl.ch>>
>     Content-Type: text/plain; charset=ISO-8859-1; DelSp="Yes";
>            format="flowed"
> 
>     Dear Sophia,
> 
>     To select which modes are Raman active you must use the selection rules.
>     The following paper may be of help (see also the tables in it):
> 
>     Rosseau et al. Journal of Raman Spectroscopy 10, 253 (1981)
> 
>     If you are starting, I recommend having a look at the selection rules
>     for molecules, for example in Tinkham, Group theory and Quantum
>     mechanics (Dover, 1992,NY) pp248.
> 
>     Most likelly, you will be interested in the allowed transitions with
>     highest
>     frequency.
> 
>     Hope this helps,
> 
>     Alexandra
> 
> 
>     Quoting Jonathan <sophia.nishad at gmail.com
>     <mailto:sophia.nishad at gmail.com>>:
> 
>      > Dear users,
>      >
>      > I computed phonons only at the gamma point for a 64-atom binary
>      > alloy. How do I separate the three main Raman modes.
>      >
>      > Would it be possible to get some help?
>      > thanks,
>      > --
>      > Sophia
>      > UCB, USA
>      >
> 
> 
> 
>     --
> 
>     Alexandra Carvalho,
>     Ceramics Laboratory
>     Swiss Federal Institute of Technology of Lausanne (EPFL)
> 
> 
> 
>     ------------------------------
> 
>     Message: 3
>     Date: Tue, 23 Jun 2009 11:29:28 +0200
>     From: Vladan Stevanovic <vladan.stevanovic at epfl.ch
>     <mailto:vladan.stevanovic at epfl.ch>>
>     Subject: [Pw_forum] Zero of the electrostatic potential ?
>     To: pw_forum at pwscf.org <mailto:pw_forum at pwscf.org>
>     Message-ID: <4A40A078.4060305 at epfl.ch <mailto:4A40A078.4060305 at epfl.ch>>
>     Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> 
>     Dear Quantum-ESPRESSO users,
> 
>     I am using QE for simulations of transition metal clusters. My question
>     is where the code places the vacuum level in such calculations
>     (nonperiodic systems in a big cell) ? To formulate differently, is it
>     possible to compare directly KS eigenvalues from different
>     calculations ?
> 
> 
>     Thanks,
>     Vladan Stevanovic
> 
>     ---------------------------------------------
>     Assistant-doctorant
>     EPFL SB IRRMA-GE
>     PH H2 435 (B?timent PH)
>     Station 3
>     CH-1015 Lausanne
>     tel. : +41 (0)21 693 51 08
>     e-mail : vladan.stevanovic at epfl.ch <mailto:vladan.stevanovic at epfl.ch>
>     ---------------------------------------------
> 
> 
> 
>     ------------------------------
> 
>     Message: 4
>     Date: Tue, 23 Jun 2009 11:46:13 +0200
>     From: Gabriele Sclauzero <sclauzer at sissa.it <mailto:sclauzer at sissa.it>>
>     Subject: Re: [Pw_forum] Zero of the electrostatic potential ?
>     To: PWSCF Forum <pw_forum at pwscf.org <mailto:pw_forum at pwscf.org>>
>     Message-ID: <4A40A465.40805 at sissa.it <mailto:4A40A465.40805 at sissa.it>>
>     Content-Type: text/plain; charset=iso-8859-1; format=flowed
> 
> 
> 
>     Vladan Stevanovic wrote:
>      > Dear Quantum-ESPRESSO users,
>      >
>      > I am using QE for simulations of transition metal clusters. My
>     question
>      > is where the code places the vacuum level in such calculations
>      > (nonperiodic systems in a big cell) ? To formulate differently, is it
> 
>     I think this question has been often posed and replied in the
>     context of work-function
>     calculation. Please first try a search on the archives using 'work
>     function' or something
>     similar as keys. You can also have a look to the example in
> 
>     examples/WorkFct_example
> 
>     in the QE folder.
> 
>      > possible to compare directly KS eigenvalues from different
>     calculations ?
> 
>     If you want compare the distance between the eigenvalues and the
>     Fermi energies in the
>     respective systems, I think you can. In order to understand if you
>     can compare the
>     absolute (i.e. not relative to E_F) value of the eigenvalues I think
>     you must first find
>     the answer to your previous question.
> 
> 
>     GS
> 
> 
>      >
>      >
>      > Thanks,
>      > Vladan Stevanovic
>      >
>      > ---------------------------------------------
>      > Assistant-doctorant
>      > EPFL SB IRRMA-GE
>      > PH H2 435 (B?timent PH)
>      > Station 3
>      > CH-1015 Lausanne
>      > tel. : +41 (0)21 693 51 08
>      > e-mail : vladan.stevanovic at epfl.ch <mailto:vladan.stevanovic at epfl.ch>
>      > ---------------------------------------------
>      >
>      > _______________________________________________
>      > Pw_forum mailing list
>      > Pw_forum at pwscf.org <mailto:Pw_forum at pwscf.org>
>      > http://www.democritos.it/mailman/listinfo/pw_forum
>      >
> 
>     --
> 
> 
>     o ------------------------------------------------ o
>     | Gabriele Sclauzero, PhD Student                  |
>     | c/o:   SISSA & CNR-INFM Democritos,              |
>     |        via Beirut 2-4, 34014 Trieste (Italy)     |
>     | email: sclauzer at sissa.it <mailto:sclauzer at sissa.it>              
>               |
>     | phone: +39 040 3787 511                          |
>     | skype: gurlonotturno                             |
>     o ------------------------------------------------ o
> 
> 
>     ------------------------------
> 
>     Message: 5
>     Date: Tue, 23 Jun 2009 12:00:01 +0200
>     From: "Lorenzo Paulatto" <paulatto at sissa.it <mailto:paulatto at sissa.it>>
>     Subject: Re: [Pw_forum] Zero of the electrostatic potential ?
>     To: vladan.stevanovic at epfl.ch <mailto:vladan.stevanovic at epfl.ch>,
>     "PWSCF Forum" <pw_forum at pwscf.org <mailto:pw_forum at pwscf.org>>
>     Message-ID: <op.uvy12b18a8x26q at paulax>
>     Content-Type: text/plain; charset=utf-8; format=flowed; delsp=yes
> 
>     In data 23 giugno 2009 alle ore 11:29:28, Vladan Stevanovic
>     <vladan.stevanovic at epfl.ch <mailto:vladan.stevanovic at epfl.ch>> ha
>     scritto:
>      > I am using QE for simulations of transition metal clusters. My
>     question
>      > is where the code places the vacuum level in such calculations
>      > (nonperiodic systems in a big cell) ?
> 
>     Dear Vladan,
>     a non-periodic system in a big periodic cell is still a periodic system!
>     Hence, the integral of the potential over any possible choice of
>     primitive
>     cell has to be zero. This is a sufficient condition to find the zero.
> 
>      > To formulate differently, is it
>      > possible to compare directly KS eigenvalues from different
>     calculations ?
> 
>     In general it is NOT possible to directly compare eigenvalues of
>     different
>     calculations, nevertheless they can be compared taking the Fermi
>     energy as
>     reference.
> 
>     best regards
> 
>     --
>     Lorenzo Paulatto
>     SISSA  &  DEMOCRITOS (Trieste)
>     phone: +39 040 3787 511
>     skype: paulatz
>     www:   http://people.sissa.it/~paulatto/
> 
>         *** save italian brains ***
>      http://saveitalianbrains.wordpress.com/
> 
> 
>     ------------------------------
> 
>     Message: 6
>     Date: Tue, 23 Jun 2009 12:08:03 +0200
>     From: Stefano de Gironcoli <degironc at sissa.it
>     <mailto:degironc at sissa.it>>
>     Subject: Re: [Pw_forum] Zero of the electrostatic potential ?
>     To: vladan.stevanovic at epfl.ch <mailto:vladan.stevanovic at epfl.ch>,
>     PWSCF Forum <pw_forum at pwscf.org <mailto:pw_forum at pwscf.org>>
>     Message-ID: <4A40A983.7080108 at sissa.it
>     <mailto:4A40A983.7080108 at sissa.it>>
>     Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> 
>     The zero of the potential energy is the average electrostatic potential;
>     as such the eigenvalues in different systems cannot be  directly
>     compared.
>     what you need yo do is to calculate the (electrostatic) potential energy
>     in the vacuum region where it should, at least for neutral systems,  be
>     constant and take that as the zero of the energy.
>     In order to calculate the potential in the vacuum region one could adapt
>     the example for the calculation of the Work Function in directory
>     examples/WorkFct_example.
> 
>     stefano
> 
>     Vladan Stevanovic wrote:
>      > Dear Quantum-ESPRESSO users,
>      >
>      > I am using QE for simulations of transition metal clusters. My
>     question
>      > is where the code places the vacuum level in such calculations
>      > (nonperiodic systems in a big cell) ? To formulate differently, is it
>      > possible to compare directly KS eigenvalues from different
>     calculations ?
>      >
> 
>      > Thanks,
>      > Vladan Stevanovic
>      >
>      > ---------------------------------------------
>      > Assistant-doctorant
>      > EPFL SB IRRMA-GE
>      > PH H2 435 (B?timent PH)
>      > Station 3
>      > CH-1015 Lausanne
>      > tel. : +41 (0)21 693 51 08
>      > e-mail : vladan.stevanovic at epfl.ch <mailto:vladan.stevanovic at epfl.ch>
>      > ---------------------------------------------
>      >
>      > _______________________________________________
>      > Pw_forum mailing list
>      > Pw_forum at pwscf.org <mailto:Pw_forum at pwscf.org>
>      > http://www.democritos.it/mailman/listinfo/pw_forum
>      >
> 
> 
> 
>     ------------------------------
> 
>     Message: 7
>     Date: Tue, 23 Jun 2009 12:07:10 +0200
>     From: Paolo Giannozzi <giannozz at democritos.it
>     <mailto:giannozz at democritos.it>>
>     Subject: Re: [Pw_forum] Zero of the electrostatic potential ?
>     To: vladan.stevanovic at epfl.ch <mailto:vladan.stevanovic at epfl.ch>,
>     PWSCF Forum <pw_forum at pwscf.org <mailto:pw_forum at pwscf.org>>
>     Message-ID: <8CD924AB-2D4E-402A-BF90-A3A392886FBB at democritos.it
>     <mailto:8CD924AB-2D4E-402A-BF90-A3A392886FBB at democritos.it>>
>     Content-Type: text/plain; charset="us-ascii"
> 
> 
>     On Jun 23, 2009, at 11:29 , Vladan Stevanovic wrote:
> 
>      > where the code places the vacuum level in such calculations
>      > (nonperiodic systems in a big cell) ? To formulate differently,
>      > is it possible to compare directly KS eigenvalues from different
>      > calculations ?
> 
>     short answer: no.
> 
>     V(G=0) is calculated (finite or infinite systems doesn't matter)
>     as described in the attached notes. CP and PWscf have a
>     different definition of V(0) so you get the same eigenvalues,
>     but displaced
> 
>     P.
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> 
>     ---
>     Paolo Giannozzi, Dept of Physics, University of 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 <mailto:Pw_forum at pwscf.org>
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> 
> 
>     End of Pw_forum Digest, Vol 24, Issue 49
>     ****************************************
> 
> 
> 
> 
> -- 
> Sincerely
> 
> Jay
> 
> 
> ==============================================
> cn:       Li, Jiaye
> en:       Jay Y. Lee
> 
> M.S. in designing and developing novel materials
> 
> Research experience:
> *ALD precursor. ie. Metal complexes
> *Surface modification. ie. Indium tin oxide, SiO2
> *Gas storage and adsorption. ie. Ionic Liquids
> 
> Skills:
> *ab-initial method, DFT simulation and Force Field simulation
> 
> Please contact me at:
> 1. jameslipd at gmail.com <mailto:jameslipd at gmail.com>  or
> 2. jameslibd at gmail.com <mailto:jameslibd at gmail.com>
> 
> ==============================================
> 
> 
> ------------------------------------------------------------------------
> 
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum

-- 


o ------------------------------------------------ o
| Gabriele Sclauzero, PhD Student                  |
| c/o:   SISSA & CNR-INFM Democritos,              |
|        via Beirut 2-4, 34014 Trieste (Italy)     |
| email: sclauzer at sissa.it                         |
| phone: +39 040 3787 511                          |
| skype: gurlonotturno                             |
o ------------------------------------------------ o



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