[Pw_forum] pwcond-problem with linear system

2009-07-22 Thread ambavale sagar
Dear all,
I am running a pwcond program for system made of Al electrodes and vaccum (> 10 
angstrom) in between. Even for such a large vaccum I get nonzero values (10e-1 
to 10e-4) of transmission coefficient (T) at higher energies (> 2 eV +Ef). for 
energies < 2 eV, T become almost zero. After 0.8 eV +Ef energy the program got 
terminated giving error:
 error # 5411
problems with the linear system. 
What might be a source of error in my case? Can I substract this contribution 
of leads from the T values I got for electrode-molecule-electrode system to get 
accurate T in case of molecule attached to electrodes?
The other question is little sidelined. Why Al is not used as electrode in most 
of the studies? In other words, what are the drawbacks of using Al as an 
electrode?

regards
Sagar Ambavale
PhD student
M.S. University of Baroda
India



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[Pw_forum] correction to functional.f90 (4.1): optx identified as a meta-GGA functional

2009-07-22 Thread Latévi Max LAWSON DAKU
Hi,

Line 399 of functional.f90:

ismeta =  (igcx == 7) .or. (igcx == 6 )

should be changed to

ismeta =  (igcx == 7)

That is, the OPTX functional was flagged as a meta-GGA.


I noticed this while trying to generate a pseudopotential
with ld1.x  using the OLYP functional (input key "olyp").

By the way, the following comment is written in functional.90.

  !  "olyp"  = "nox+lyp+optx+blyp"!!! UNTESTED !!!

Does this mean, simply, that the olyp shortname is not well tested?
or something else?


By the way, I noticed that the keyword "blyp" is used for designating
both the blyp XC functional and the lyp gradient correction to
correlation. This perhaps explains that the following error message

 from set_dft_value : error # 1
 two conflicting matching values

was issued when I tried to specify the olyp functional as follows:

'nox-lyp-optx-blyp'

This is a guess based on the presence of Line 261:

if (matches ('BLYP', dftout) ) call set_dft_value (igcx, 1)



Finally, I've inserted the following lines in the subroutine dft_name(),
Line 609:

  else if (iexch_==0.and.icorr_==3.and.igcx_==6.and.igcc_==3) then
 shortname_ = 'OLYP'


Best regards,
Max


-- 
***
Latevi Max LAWSON DAKU
Departement de chimie physique 
Universite de Geneve - Sciences II
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CH-1211 Geneve 4 
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Tel: (41) 22/379 6548 ++ Fax: (41) 22/379 6103
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[Pw_forum] Compilation using -DEXX

2009-07-22 Thread Giovanni Cantele
snd2mra at yahoo.com wrote:
> Hello,
>I am compiling the recent version of pwscf 4.1 to perform calculations 
> using the PBE0 functional. I have this doubt. Do I have to include the 
> '-DEXX' both in DFLAGS and CPPFLAGS ? The details given in the examples 
> folder suggest us to add this to just DFLAGS.
>
> Thank you.
>
> - Madan Mithra
>
>
>   
as you may see from this line in the make.sys you find in your QE top 
directory
CPPFLAGS   = -P -traditional $(DFLAGS) $(IFLAGS)
DFLAGS are included in the preproceccing flags CPPFLAGS

Giovanni 

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Coherentia CNR-INFM and Dipartimento di Scienze Fisiche
Universita' di Napoli "Federico II"
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Skype contact: giocan74



[Pw_forum] pwcond-problem with linear system

2009-07-22 Thread Manoj Srivastava
Dear Sagar, 
 The error 'Problems with the linear system' generally gets
removed if you change 'ecut2d' parameter, which is the 2D energy cutoff
and determines how many plane waves would you have in your calculation. I
am guessing that the other problem is also coming from energy convergence.
I suggest to check that.

-Manoj 

On Wed, 22 Jul 2009, ambavale sagar wrote:

> Dear all,
I am running a pwcond program for system made of Al electrodes and vaccum (> 10 
angstrom) in between. Even for such a large vaccum I get nonzero values (10e-1 
to 10e-4) of transmission coefficient (T) at higher energies (> 2 eV +Ef). for 
energies < 2 eV, T become almost zero. After 0.8 eV +Ef energy the program got 
terminated giving error: error # 5411
problems with the linear system. 
What might be a source of error in my case? Can I substract this contribution 
of leads from the T values I got for electrode-molecule-electrode system to get 
accurate T in case of molecule attached to electrodes?
The other question is little sidelined. Why Al is not used as electrode in most 
of the studies? In other words, what are the drawbacks of using Al as an 
electrode?

regards
Sagar Ambavale
PhD student
M.S. University of Baroda
India



  See the Webs breaking stories, chosen by people like you. Check out 
Yahoo! Buzz. http://in.buzz.yahoo.com/



[Pw_forum] about U

2009-07-22 Thread wangqj1

Dear matteo
 I want to compute the value of U,in the paper PRB 71, 035105 (2005),the 
Eq.(18),(19),but I don't know how to built the matrices \chi and \chi_0,I want 
to built the matrices manually instead of programe pack like your example. And 
how do I extract the the date from the out file of unperturbed self-consistent 
calculation and the files of perturbed calculations(like pert-0.1.out 
,pert-0.2.out and so on ) to construct the matrices of \chi and \chi_0 as in 
Eq.(18) ?
Beat regards
Q J Wang
XiangTan University
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[Pw_forum] Compilation using -DEXX

2009-07-22 Thread snd2...@yahoo.com

Hello,
   I am compiling the recent version of pwscf 4.1 to perform calculations 
using the PBE0 functional. I have this doubt. Do I have to include the '-DEXX' 
both in DFLAGS and CPPFLAGS ? The details given in the examples folder suggest 
us to add this to just DFLAGS.

Thank you.

- Madan Mithra

 
 Madan Mithra .L.M
 Senior Research Fellow
 Dept.of Physics
 Indian Institute of Science
 Bangalore - 560 012
 INDIA
 .
 e-mail : mit at physics.iisc.ernet.in
: snd2mra at yahoo.com
 Phone  : 91-80-22932313(Lab)
 FAX: (080) 360 2602
 -