[Pw_forum] PhD fellowships in "Computational Physics and Materials Science" at KAUST, Saudi Arabia

[nsingh]

King Abdullah University of Science and Technology (www.kaust.edu.sa)
invites applications for PhD fellowships in the field of "Computational
Physics and Materials Science".

The positions are available immediately and will be open until filled.

Potential topics include:
- Materials for thermoelectric applications
- Interfaces and surfaces
- Two-dimensional materials
- Nanoparticles for energy applications
- Correlated materials, in particular oxides
- Materials for spintronics
- Electronic transport calculations
- Molecular dynamics
- Methodology and code development

Fellowships are available for both the BSc-to-PhD (5 years) and MSc-to-PhD
(3 years) tracks. Besides free housing and health care, a generous stipend
(US $25000 and $3 per year, respectively, before and after passing the
PhD qualifying exam) is provided.

Please submit your application online through the KAUST website (
http://www.kaust.edu.sa/application-form-kaust.html) before 14 Feb 2015 and
send your application ID to nirpendra.si...@kaust.edu.sa
.
Please use the subject PhD-AUG2015.
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[Pw_forum] Excitations in Realistic Materials using Yambo on Massively Parallel Architectures

[Daniele Varsano]

The Yambo team is pleased to announce the school on:

"Excitations in Realistic Materials using Yambo on Massively Parallel 
Architectures"
that will take place from April 13 to April 17, 2015 at the CECAM headquarters 
in Lausanne (Switzerland).
The application deadline is on February 27, 2015.
http://www.cecam.org/workshop-0-1149.html 

http://www.yambo-code.org/Yambo2015/index.php 


This 5-day hands-on tutorial will provide training in the theory and practice 
of computing electronic and optical excitations within density functional and 
Green’s function approaches (GW, TDDFT and BSE). Lectures will also focus on 
the application of these techniques to the study of realistic and challenging 
systems using the Yambo code within a massively-parallel environment.

The number of participants will be limited to approx. 30.
The organization will partially cover living expenses of the participants.
Acceptance decisions will be made within 1 week after the deadline on the basis 
of motivations and CV provided at the moment of application.
For more details, please follow the above links.

School long description:
===
Yambo is  a powerful, open-source ab-initio code interfaced with several DFT 
packages (including Abinit and quantum-ESPRESSO). This tutorial will mark the 
release of a completely new version of Yambo which is thought for 
massively-parallel, distributed memory computing architectures following the 
current trends in high-performance computing.  The new features require 
specially skilled users in order to boost the code performance and efficiently 
obtain accurate results for large, realistic systems.
Our goal is to thus equip students with the fundamental knowledge, practical 
skills and computational tools needed to tackle today’s challenging problems in 
materials science.

Lectures on the foundations of the theoretical methods will be complemented by 
technical ones on numerical and computational aspects. A significant part of 
the school will be dedicated to hands-on tutorials, where participants will be 
given the opportunity to carry out excited state calculations on several 
paradigmatic systems under the guidance of the Yambo code developers themselves.

With kind regards,
the Yambo Team

---
Daniele Varsano, PhD
Centro S3, CNR Institute of Nanoscience
Via Campi 213/A, 41125 Modena, Italy
e-mail:  daniele.vars...@nano.cnr.it 
Skype: daniele.varsano
URL:  http://www.nano.cnr.it  
ph:  +39-059-205-5276
fax:  +39-059-205-5651___
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Re: [Pw_forum] difference in output from dynmat.x and matdyn.x

[Sridhar Sadasivam]

Dear Lorenzo,
I apologize for getting back so late on this. I had posted a reply but
looks like the email bounced back due to some size restriction on the
attachment. But to answer your question, I did not find a negative
frequency anywhere else in the q-point grid. I am attaching my scf, ph, q2r
and matdyn input files. I am facing the same problem with another crystal
structure of SiO2 as well (cristobalite). I feel like I am making some
mistake in the input files that is probably important for polar materials.

I would really appreciate it if someone could look into it. Thanks!
Sridhar
Purdue University

On Mon, Nov 17, 2014 at 2:34 AM, Lorenzo Paulatto <
lorenzo.paula...@impmc.upmc.fr> wrote:

>  Dear Sridhar,
> normally the sum rules imposed by matdyn are enough to set the acoustic
> bands at gamma to exactly zero. If this is not the case, it normally means
> that you have some negative frequency somewhere else in the q-point grid.
> Please check the other matdyn files to see if this is the case: the
> frequencies are at the end of the file.
>
> kind regards
>
>
>
> On 17/11/14 02:03, Sridhar Sadasivam wrote:
>
> Dear Stefano,
>
>  Thanks for your reply. Here are the frequencies at gamma point when I
> set zasr and asr to 'simple'
>-12.8981  -12.8981   -4.5998  142.6073  168.0267  168.0267
>   249.0588  249.0588  340.4760  344.4668  379.2589  379.2589
>   417.0274  417.0274  429.6273  457.2113  657.8050  657.8050
>   746.0641  755.8553  755.8553 1032.5200 1032.5200 1037.0491
>  1048.5362 1136.7760 1136.7760
>
>  Thanks,
> Sridhar
>
> On Sun, Nov 16, 2014 at 5:25 AM, stefano de gironcoli 
> wrote:
>
>>  dear Sridhar Sadasivam
>>   can you try to set zasr and asr to 'simple' in the q2r+matdyn case
>> and report the results ?
>>   thanks
>> stefano
>>
>>
>>
>> On 11/15/2014 11:49 PM, Sridhar Sadasivam wrote:
>>
>>  Dear espresso users and developers,
>>
>>  I am trying to obtain the phonon dispersion of alpha-quartz (SiO2)
>> which has a 9 atom unit cell. I ran ph.x on a 3 x 3 x 3 q-point grid. I am
>> seeing some strange behavior where there seems to be a difference in the
>> frequencies output from dynmat.x and matdyn.x. I will explain my problem
>> below.
>>
>>  I diagonalized the dynamical matrix at the gamma point using dynmat.x
>> with acoustic sum rule set to crsytal. Since SiO2 is a polar material,
>> LO-TO splitting will need to be considered at the gamma point but I am
>> ignoring it currently (I did not specify any direction for LO-TO splitting
>> in the dynmat.x input). This gave me the following 27 frequencies (in
>> cm^-1) at the gamma point: (0,0,0, 152.24, 175.57, 175.57, 256.32, 256.32,
>> 341.09, 354.41, 376.86, 376.86, 419.01, 419.01, 435.37, 455.70, 659.12,
>> 659.12, 744.54, 754.62, 1034.38, 1034.38, 1040.20, 1051.12, 1139.60,
>> 1139.60)
>>
>>  I also used q2r.x (with zasr = 'crystal') to obtain the force constants
>> and then used matdyn.x (with asr = 'crystal') to obtain the frequencies at
>> the gamma point. However with matdyn.x, I obtain the following frequencies
>> at the gamma point: (-29.4088,-22.2535,-22.2535,152.2412,175.8141,175.8141,
>> 256.3373, 256.3373, 341.0892, 355.4227, 376.0495 , 376.0495, 418.6344,
>> 418.6344, 435.3710, 453.6862, 659.7607, 659.7607, 746.4843, 754.8867,
>> 754.8867, 1034.1751, 1034.1751, 1039.7590, 1051.1207, 1139.8191, 1139.8191)
>>
>>  Could someone please explain why I am getting imaginary frequencies
>> from matdyn.x while dynmat.x gives real frequencies at the same q-point
>> (gamma in this case)?
>>
>>  Thanks,
>> Sridhar
>> Purdue University
>>
>>
>>
>>  ___
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>>
>>
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>
>
>
> ___
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>
>
> --
> Dr. Lorenzo Paulatto
> IdR @ IMPMC -- CNRS & Université Paris 6
> +33 (0)1 44 275 084 / skype: paulatzhttp://www-int.impmc.upmc.fr/~paulatto/
> 23-24/4é16 Boîte courrier 115, 4 place Jussieu 75252 Paris Cédex 05
>
>
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SiO2.in
Description: Binary data


matdyn.in.freq
Description: Binary data


q2r.in
Description: Binary data


ph_1.in
Description: Binary data
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[Pw_forum] How to calculate the Raman spectra?

[于海林]

Dear all,
How to calculate the Raman spectra of GaN after a scf calculation? Thanks in 
advance!


Best Regards!


Yu Hailin


College of Physics & Electronic Enginerring,
Changshu Institute of Technology
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Re: [Pw_forum] "eigenvalues not converged" warnings appear in one compilation but does not appear in another

[Paolo Giannozzi]

Short answer: no. Different compilers and (especially) different 
mathematical libraries may (and usually do) produce slightly different
numbers. As long as you converge to the same (or "sufficiently same")
results, nothing to worry about. The day you will write some serious
piece of code, however, keep this fact is mind.

Paolo

On Mon, 2015-01-12 at 15:45 +0300, Uri Argaman wrote:
> Dear QE users and developers
> 
> I compile QE version 5.0.3 on cluster with Intel compilers and I got
> no warnings in some PW calculation. When I run the same input in
> another machine with another compilation I got the warning: "c_bands:
> 1 eigenvalues not converged" several times. I want to mention that
> this warning did not appear in the last SCF cycle and there is no
> difference in the energy. There is a very small difference in the
> stress. Do I have something to worry about?
> 
> 

> 
> Uri Argaman
> 
> Ben-Gurion University of the Negev
> 
> Israel
> 
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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 

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Re: [Pw_forum] "eigenvalues not converged" warnings appear in one compilation but does not appear in another

[xiaochuan Ge]

Dear Argaman,
I am not an expert in this issue, but according to my opinion, as long as
the last SCF cycle converges, you should not worry about the result.
Besides, if this bothers you anyways, you may also want to try to change
the  "startingwfc" you use and see if it solves your problem.

Best,

===
Dr. Xiaochuan Ge (Giovanni)
Center for Functional Nanomaterials
Brookhaven national laboratory
===

On 12 January 2015 at 07:45, Uri Argaman  wrote:

> Dear QE users and developers
> I compile QE version 5.0.3 on cluster with Intel compilers and I got no
> warnings in some PW calculation. When I run the same input in another
> machine with another compilation I got the warning: "c_bands:  1
> eigenvalues not converged" several times. I want to mention that this
> warning did not appear in the last SCF cycle and there is no difference in
> the energy. There is a very small difference in the stress. Do I have
> something to worry about?
>
> Uri Argaman
> Ben-Gurion University of the Negev
> Israel
>
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[Pw_forum] Excitations in Realistic Materials using Yambo on Massively Parallel Architectures

[Daniele Varsano]

The Yambo team is pleased to announce the school on:

"Excitations in Realistic Materials using Yambo on Massively Parallel 
Architectures"
that will take place from April 13 to April 17, 2015 at the CECAM headquarters 
in Lausanne (Switzerland).
The application deadline is on February 27, 2015.
http://www.cecam.org/workshop-0-1149.html 

http://www.yambo-code.org/Yambo2015/index.php 


This 5-day hands-on tutorial will provide training in the theory and practice 
of computing electronic and optical excitations within density functional and 
Green’s function approaches (GW, TDDFT and BSE). Lectures will also focus on 
the application of these techniques to the study of realistic and challenging 
systems using the Yambo code within a massively-parallel environment.

The number of participants will be limited to approx. 30.
The organization will partially cover living expenses of the participants.
Acceptance decisions will be made within 1 week after the deadline on the basis 
of motivations and CV provided at the moment of application.
For more details, please follow the above links.

School long description:
===
Yambo is  a powerful, open-source ab-initio code interfaced with several DFT 
packages (including Abinit and quantum-ESPRESSO). This tutorial will mark the 
release of a completely new version of Yambo which is thought for 
massively-parallel, distributed memory computing architectures following the 
current trends in high-performance computing.  The new features require 
specially skilled users in order to boost the code performance and efficiently 
obtain accurate results for large, realistic systems.
Our goal is to thus equip students with the fundamental knowledge, practical 
skills and computational tools needed to tackle today’s challenging problems in 
materials science.

Lectures on the foundations of the theoretical methods will be complemented by 
technical ones on numerical and computational aspects. A significant part of 
the school will be dedicated to hands-on tutorials, where participants will be 
given the opportunity to carry out excited state calculations on several 
paradigmatic systems under the guidance of the Yambo code developers themselves.

With kind regards,
the Yambo Team

---
Daniele Varsano, PhD
Centro S3, CNR Institute of Nanoscience
Via Campi 213/A, 41125 Modena, Italy
e-mail:  daniele.vars...@nano.cnr.it
Skype: daniele.varsano
URL:  http://www.nano.cnr.it 
ph:  +39-059-205-5276
fax:  +39-059-205-5651

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[Pw_forum] "eigenvalues not converged" warnings appear in one compilation but does not appear in another

[Uri Argaman]

Dear QE users and developers
I compile QE version 5.0.3 on cluster with Intel compilers and I got no
warnings in some PW calculation. When I run the same input in another
machine with another compilation I got the warning: "c_bands:  1
eigenvalues not converged" several times. I want to mention that this
warning did not appear in the last SCF cycle and there is no difference in
the energy. There is a very small difference in the stress. Do I have
something to worry about?

Uri Argaman
Ben-Gurion University of the Negev
Israel
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Re: [Pw_forum] Electric field in silicene

[Lorenzo Paulatto]

On 10/01/15 18:41, siham Sadki wrote:

> K_POINTS {automatic}
> 10 10 1 1 1 1

Dear Siham,
using a k-point grid shifted along the Z direction is wrong for 2D 
materials, it is also probably wrong for applying dipfield.

kind regards

-- 
Dr. Lorenzo Paulatto
IdR @ IMPMC -- CNRS & Université Paris 6
+33 (0)1 44 275 084 / skype: paulatz
http://www-int.impmc.upmc.fr/~paulatto/
23-24/4é16 Boîte courrier 115, 4 place Jussieu 75252 Paris Cédex 05

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Re: [Pw_forum] Re : how to calculate U parameter

[Matteo Cococcioni]

Dear Swati,

I do not know much about ZnSe and cannot answer your first question.
Usually the +U correction is applied to atoms with d or f electrons.
As for changing the routines it should self-evident once you open them. In
set_hubbard_l you choose the l quantum number  you want to apply the U to
for a specific atom (e.g., if you correct the d states of Fe you pick l = 2
for Fe). In tabd, instead, you choose the total number of electrons (spin
up + spin down) the code places on the selected orbitals
(e.g., for Fe it is usually 6).

Hope this helps.

Matteo

On Sat, Jan 10, 2015 at 7:24 AM, Swati Khatta 
wrote:

> Dear Matteo
>
> As extension to my previous question, I still have a queries that is it
> sufficient to apply U parameter on only Zn as it is 3d element . As Se is
> 4p element so it is also necerssarily required  to apply U parameter on it
> as I do further calucations on ZnSe system And if so so how to update
> rotines set _hubbaed_l.f90 and tabd.f90.
>
>  Regards
>  swati khatta
>   panjab University
>   chandigarh
>
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Re: [Pw_forum] Electric field in silicene

[Gabriele Sclauzero]

Silicene is a 2D material and you have vacuum between its periodic 
repetitions.
Therefore the sawtooth potential (tefield=.true.) is also a viable 
solution. Have you tried that?


HTH

GS

On 01/10/2015 06:41 PM, siham Sadki wrote:



Dear all,

I am wanting to get the Dos of silicene under the effect of an
external electric field. I have done the scf calculations without
electric field , then again did the scf calculation with an electric
field included in the z-direction (with value 0.008ua). But the
convergence is not achieved and it stopped after 100 iterations and
giving it this message:

"convergence NOT achieved after 100 iterations: stopping"

You will find below  in file for the scf calculation when an
electric field is applied:
 &control
calculation = 'scf'
restart_mode='from_scratch',
prefix='Si11ca00E0.008',
lelfield=.true.,
nberrycyc=3
gdir=3
pseudo_dir ='/home/siham/Desktop/espresso-5.0.1-GPU/pseudo',
outdir='/home/siham/Desktop/espresso-5.0.1-GPU/tmp'
   /
 &system
ibrav= 4,
celldm(1)=7.3103,
celldm(3)= 5,
nat= 2, ntyp= 1,
ecutwfc = 50.0,
ecutrho =370.0
nbnd = 12,
  /
 &electrons
   conv_thr =  1.0d-8
   mixing_beta = 0.2
   efield_cart(1)=0.d0, efield_cart(2)=0.d0, efield_cart(3)=0.008d0
 /
 &ions
  /
ATOMIC_SPECIES
 Si 28.086  Si.pbe-rrkj.UPF
ATOMIC_POSITIONS (Angstrom)
 Si   0.0   0.0 2.001457804
 Si   -0.00019   2.233446401   2.447251213
K_POINTS {automatic}
10 10 1 1 1 1
Thanks in advance




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