[Pw_forum] Transition state calculation error

[Cecil Humphrey Botchway]

Hi There,
I am trying to run a transition state calculation using neb.x with methanol
C-OH bond breaking in the zeolite micro pore (the system is composed of 120
atoms). I have tried relaxing the whole structure with the adsorbate and
freezing only the zeolite leaving the adsorbate. I have even tried
increasing and decreasing the numbers of processor cores from 8-16. I
encounter the same error (which is below) regardless .


 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     task #         0
     from rdiaghg : error #       818
     S matrix not positive definite
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


What could be the possible cause?
This is how my input looks like

BEGIN
BEGIN_PATH_INPUT
&PATH
  restart_mode      = 'from_scratch'
  string_method     = 'neb',
  nstep_path        = 20,
  ds                = 2.D0,
  opt_scheme        = "broyden",
  num_of_images     = 7,
  k_max             = 0.3D0,
  k_min             = 0.2D0,
  CI_scheme         = "auto",
  path_thr          = 0.1D0,
/
END_PATH_INPUT
BEGIN_ENGINE_INPUT
&CONTROL
  prefix         = "TS1"
  outdir         = "./tmp/",
  pseudo_dir     = "/home/cbotchway/Cecil",
/
&SYSTEM
  ibrav                  = 0,
  nat                    = 120,
  ntyp                   = 5,
  ecutwfc                = 40.0D0,
  ecutrho                = 240.0D0,
  nspin                  = 2,
  starting_magnetization = 0.5D0,
  occupations            = "smearing",
  degauss                = 0.03D0,
/
&ELECTRONS
  conv_thr    = 1.D-6,
  mixing_beta = 0.2D0,
  electron_maxstep =1000000,
/
&IONS
/
ATOMIC_SPECIES
O    15.99940    O.pbe-van_ak.UPF
Si   28.0855    Si.pbe-n-van.UPF
Al   26.98154   Al.pbe-n-van.UPF
H     1.00794    H.pbe-van_ak.UPF
C    12.0107     C.pbe-van_ak.UPF
BEGIN_POSITIONS
FIRST_IMAGE

Attached to this post is a copy of my input file
Any help or advice would be appreciated
Thank you in advance
-- 
Cecil Huymphrey Botchway
Mphil. Material Science and Computational Chemistry
Department of Chemistry
Kwame Nkrumah University of Science and Technology
+23329002372
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20160503/2383f34a/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: FERmepos2p.in
Type: application/octet-stream
Size: 42806 bytes
Desc: not available
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20160503/2383f34a/attachment.obj>