[Pw_forum] Fermi Energy Caculation

[Paolo Giannozzi]

Please see items  11.7.0.8, 11.7.0.9 and 11.7.0.11 of
the user guide:
http://www.quantum-espresso.org/user_guide/ 
node60.html#SECTION000127080

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

[Pw_forum] ibrav=12

[Paolo Giannozzi]

On Feb 19, 2011, at 15:55 , Carlo Nervi wrote:

> I've been confused by the convenction used in quantum espresso.

the conventions used in QE for lattices are explained in detail in the
documentation. They may not be the smartest or the "more standard"
choice, though (not sure what is considered "standard" in  
crystallography).
Any proposal for improvement is welcome, as long as
- it is written in fortran and ready to be plugged into the code, and
- it is backward-compatible (does not affect existing input data).
An ugly but safe and straightforward way to achieve this is to define
more values of "ibrav". The relevant parts of code are the 30 lines or
so starting from
   IF ( celldm_(1) == 0.D0 .and. a /= 0.D0 ) THEN
in PW/input.f90, plus flib/latgen.f90

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

[Pw_forum] ZnO(1010) surface BandGap

[meysam pazoki]

Dear Giuseppe
Thanks for your reply.
In Bulk ZnO with GGA ,i have 1.2 eV Gap but in the slab it is approximately
disappeared.
What is wrong with ZnO surface?I dont know why in calculation of surface
,the gap is disappeared.
Best Regards
meysam
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[Pw_forum] Fermi Energy Caculation

[meysam pazoki]

-- Forwarded message --
From: meysam pazoki <meysam.paz...@gmail.com>
Date: Sat, Feb 19, 2011 at 4:33 PM
Subject: Re: Fermi Energy Caculation
To: pw_forum at pwscf.org


Dear xirainbow
Thanks for your comment. Each semiconductor have a fermi energy level.
The exact value of fermi energy (relative to vaccum level) depicts that the
contact of this semiconductor with Au(for example) is *Schottky* or ohmic.
Or for example when this semiconductor is in contact with a Red/Ox
electrolyte ,what is the length of double layer ?
This is duo to when a metal and a semiconductor are in contact, in
equilibrium the fermi energy of two systems should be identical(Fermi
energy  (with good approximation) is equal to chemical potential. Chemical
potential is energy of adding 1 electron to the system.In equilibrium there
is no electronic current between two parts. )
But when you work with two samples in contact to each other you need to know
the value of fermi energy relative to vaccum.
Best wishes
meysam
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[Pw_forum] ibrav=12

[Carlo Nervi]

Dear Paul,
commenting your note, and as a chemist, I've been confused
by the convenction used in quantum espresso.
I'm using a, b, c, alpha, beta and gamma, but not always
I've been able to directly translate the content of cif
files into QE input...
Here is an example about monoclinic input:
http://www.democritos.it/pipermail/pw_forum/2010-February/015993.html

I had to switch (b, c) in the cell and (y, z) in the data

Finally i decided to use only triclinic for all input
files, regardless of the real ibrav...

Just my 2c...

Carlo

--
--
Carlo Nervi carlo.nervi at unito.it Tel:+39 011 6707507/8
Fax: +39 011 6707855 - Dipartimento di Chimica IFM
via P. Giuria 7, 10125 Torino, Italy
http://lem.ch.unito.it/

>
>
> -- Messaggio originale ---
> Oggetto: Re: [Pw_forum] ibrav=12
> Da:  "W2AGZ" 
> Data:Ven, 18 Febbraio 2011, 8:43 pm
> A:   "'PWSCF Forum'" 
> --
>
> Thanks, Eyvaz.  The space group I???m interested in is
> P21/c  (14).  8 atoms per unit cell, 24 IRs.  If you need
> a beta tester, just ask.  -Paul
>
>
>
> From: pw_forum-bounces at pwscf.org
> [mailto:pw_forum-bounces at pwscf.org] On Behalf Of Eyvaz
> Isaev
> Sent: Friday, February 18, 2011 9:05 AM
> To: PWSCF Forum
> Subject: Re: [Pw_forum] ibrav=12
>
>
>
> Dear Paul,
>
> In fact, I am working on this problem in order to support
> in PlotPhon almost all lattice types. I will let you know
> soon, hopefully.
>
>
> Best regards,
> 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
>
>
>
>
>
>   _
>
> From: W2AGZ 
> To: pw_forum at pwscf.org
> Sent: Fri, February 18, 2011 10:06:08 AM
> Subject: [Pw_forum] ibrav=12
>
> To All (especially Eyvaz):
>
>
>
> I would like to create a file for PlotPhon/Include to
> support general monoclinic structures.  Below is the
> Include file for orthorhombic as an example ???kick
> off:??
>
>
>
> # Simple Orthorhombic lattice (X=b/a, Y=c/a)
>
>   1.0  0.0   0
>
>   0.0  XX0
>
>   0.0  0.0   YY
>
> # With respect to basis vectors
>
> 1   0.0  0.0   0.5Z
>
> 50  0.0  0.0   0.0G
>
> 50  0.50 0.0   0.0X
>
> 50  0.50 0.5   0.0S
>
> 50  0.00 0.5   0.0Y
>
> 50  0.00 0.0   0.0G
>
> 50  0.50 0.5   0.5R
>
>
>
> Now, the ???popular?? cell convention for
monoclinic
> structures is either ???b-axis-unique,?? or
> ???c-axis-unique.??  PWgui and PWscf prefer the
latter,
> but that???s OK, since it???s a simple transformation, as
> least in direct space, between the two.  But, what is the
> appropiate ???include?? for ibrav=12 ???c-axis
unique???
>  I???ve been to ???BILBOA,?? and the
> Bouchaert-Smoluchowski-Wigner path I want is
> gamma-a-u-e-z-lambda-gamma for both electrons and phonons.
>  Incidentally, when I was a graduate student, the legend
> was that the BSW notation was invented by physicists to
> purposely confuse chemists.  So, please tell me how to
> construct the appropriate ???scripts/lines?? and
> ???include?? files accordingly.
>
>
>
> Grazi, Paul Grant
>
> IBM Research Staff Member Emeritus
>
> www.w2agz.com
>
>
>
> Addenda...I include the following at the risk of angering
> Santo Paolo who may excommunicate me from the forum on the
> basis of ???topic out of bounds.?? ???Mea
culpa...dominus
> noster...??  Therefore I apologize for this
posting and
> to those for whom English is not their native language,
> especially Americans, Australians, Kiwis, Irish, Scots,
> Welsh, Cornish, Indians and particularly Quebecois
> (British Columbians excepted).
>
>
>
> 2011 is the 100th anniversary of the discovery of
> superconductivity and the 25th of above liquid nitrogen in
> copper oxide perovskites.  I will be giving one of the
> plenary talks at the upcoming APS March Meeting in
> Dallas...go here
>   for
> the epitome.  And later a reprise at the MRS April Meeting
> in San Francisco.  But, in addition, I will also present a
> contributed talk at each meeting on ???proxy?? CuO
> structures based entirely on Quantum Espresso
> resources...go here
>   to
> see.
>
>
>
> I would love to see and meet members of the QE community
> at each event...and offer a ???real espresso??
beverage.
>  Look for me outside any of the superconductivity
> sessions, or inquire in the press room.  I???m reasonably
> identifiable...an old guy with long white hair and beard.
>  Hmm...well...maybe not that unique!
>
>
>
>
>
> ___
> Pw_forum mailing list
> 

[Pw_forum] classical potential MD simulation

[Giovanni La Penna]

It may be possible to make QM/MM with QE and
some empirical MD package. Some years ago a sort
of plugin was build for DLPOLY/Siesta:

J. Torras et al., PUPIL: a systematic approach to
software integration in multi-scale simulations
Comp. Phys. Commun. 177, 265 (2007).

Maybe, with a limited amount of work, additional
software, etc.. There is a big problem with PBC
for QM area merged into a classical system larger
than QM boundaries.

 Giovanni


Giovanni La Penna - National research council (Cnr)
Institute for chemistry of organo-metallic compounds (Iccom)
via Madonna del Piano 10,
I-50019 Sesto Fiorentino, Firenze, Italy
tel.: +39 055 522-5264, fax: +39 055 522-5203
e-mail: glapenna at iccom.cnr.it - http://www.iccom.cnr.it/lapenna
skype: giovannilapenna

[Pw_forum] Fermi Energy Caculation

[jia chen]

Dear Pazoki,

You can calculate work function for certain surfaces in pp.

Best Wishes
Jia

On Sat, Feb 19, 2011 at 8:04 AM, meysam pazoki
 wrote:
>
>
> -- Forwarded message --
> From: meysam pazoki 
> Date: Sat, Feb 19, 2011 at 4:33 PM
> Subject: Re: Fermi Energy Caculation
> To: pw_forum at pwscf.org
>
>
> Dear xirainbow
> Thanks for your comment. Each semiconductor have a fermi energy level.
> The exact value of fermi energy (relative to vaccum level) depicts that the 
> contact of this semiconductor with Au(for example) is Schottky or ohmic.
> Or for example when this semiconductor is in contact with a Red/Ox 
> electrolyte ,what is the length of double layer ?
> This is duo to when a metal and a semiconductor are in contact, in 
> equilibrium the fermi energy of two systems should be identical(Fermi energy? 
> (with good approximation) is equal to chemical potential. Chemical potential 
> is energy of adding 1 electron to the system.In equilibrium there is no 
> electronic current between two parts. )
> But when you work with two samples in contact to each other you need to know 
> the value of fermi energy relative to vaccum.
> Best wishes
> meysam
>
>
>
>
> ___
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum
>



--
Jia Chen

[Pw_forum] classical potential MD simulation

[sakthi kumaran]

Dear all,
Is it possible to compute the interaction between two capped
nanotubes facing each other using classical LJ12 potential using Molecular
dynamics technique in Quantum espresso.If possible what is the procedure for
doing so.

Thank you guys in advance
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[Pw_forum] classical potential MD simulation

[Changru Ma]

Dear sakthi kumaran,

It's not possible to perform classical molecular dynamics in Quantum Espresso 
now. QE can do ab-initio molecular dynamics: Car-Parrinello Molecular Dynamics 
and Born-Oppenheimer Molecular Dynamics.

PS. Next time please take a few seconds to sign your post with your affiliation.

Best wishes,
Changru

On 19 Feb, 2011, at 07:28, sakthi kumaran wrote:

> Dear all,
> Is it possible to compute the interaction between two capped 
> nanotubes facing each other using classical LJ12 potential using Molecular 
> dynamics technique in Quantum espresso.If possible what is the procedure for 
> doing so.
>  
> Thank you guys in advance
> ___
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum

---
Changru Ma
SISSA & Theory at Elettra group
email: crma at sissa.it
tel: +39 040 375 8713 (Elettra)
  +39 040 378 7870 (SISSA)
http://www.sissa.it/~crma
---