[Pw_forum] Transition state calculation error

[Paolo Giannozzi]

This is unfortunately a nasty error that is not easy to solve. It is either
due to pseudopotentials or to really bad structures. If the problem arises
in the first NEB step, verify that your starting positions do not have
atoms too close

Paolo

On Tue, May 3, 2016 at 2:48 PM, Cecil Humphrey Botchway <
humphrey2g4 at gmail.com> wrote:

> 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
>
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>



-- 
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222
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