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 < [email protected]> 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 > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum > -- 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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