[Pw_forum] NEB Calculation with Ti and Graphene

[Eyvaz Isaev]

Dear Ettore,


The best hints are 

1) Searching the forum archive, as the same question was submitted just  few 
days ago.
2) Read User's Guide, page 54 (for QE 4.2)

Hope this will help you to find the answer to fix your problem.

Bests,
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



----- Original Message ----
From: Ettore Baldini Neto <neto.baldini at gmail.com>
To: PWSCF Forum <pw_forum at pwscf.org>
Sent: Fri, December 17, 2010 11:15:58 PM
Subject: [Pw_forum] NEB Calculation with Ti and Graphene

Dear users,

I'm playing with a NEB calculation involving one Ti atom in a graphene 
monolayer.
The calculation crashes due to diagonalization problems according to the message 
below.
*******************************************
   task #         8
     from cdiaghg : error #       434
     diagonalization (ZHEGV*) failed
********************************************

In what follows I copied my input file (without the atomic positions in order to 
make it small for the readers)
Any hint? Am I doing something very wrong? 
I'm not using for now polarization for Ti for now in order to make things 
simpler. I'm planning to include it soon.
Also, I'm using a large ecut but I figured out that for graphene and for this 
pseudo 35-40Ry might work fine.

title = 'Graphene mono layer'
   calculation =   "neb"   ,
   restart_mode = 'from_scratch' ,
   outdir='/home/usuarios/baldini/espresso-4.2.1/tmp/' ,
   pseudo_dir = '/home/usuarios/baldini/espresso-4.2.1/pseudo' ,
               etot_conv_thr = 1.0E-3  ,
               forc_conv_thr = 1.0D-4 ,
               nstep=10,
               prefix='1MLG_Ti_NEB',
/
&SYSTEM
                       ibrav = 0.,
                       ntyp = 2 ,
                       nat = 33 ,
                       ecutwfc = 50.0 ,
                       ecutrho = 400.0,
                       occupations = 'smearing' ,
                       degauss = 0.02,
                       smearing = 'mv' ,
/
&ELECTRONS
             conv_thr  =  1.0d-7  ,
             mixing_beta = 0.4 ,
/
&IONS
  num_of_images     = 4,
  opt_scheme        = "broyden",
  path_thr          = 0.03D0,
/
ATOMIC_SPECIES
C   12.0107   C.pbe-van_ak.UPF
Ti  47.8670   Ti.pbe-sp-van_ak.UPF
CELL_PARAMETERS
16.12131954   9.383047808   0.0000000
0.00000000  18.658162370   0.0000000
0.0000000    0.000000000  56.6893424
ATOMIC_POSITIONS  angstrom 
first_image
...
last image
.......
K_POINTS {automatic} 
6.0 6.0 1.0 1.0 1.0 1.0


Thanks a lot and best regards

************************************************************************
Dr. Ettore Baldini-Neto,
Researcher at Wernher von Braun Center of Advanced Research 
Campinas, Brazil
***********************************************************************


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