<div dir="ltr"><div><div><div><div><div>Hi There,<br></div>I have been trying to run a neb.x calculation with methanol bond breaking i the zeolite micropore ( the system is composed of 120m atoms). I keep getting the error below<br><br> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%<br>     task #         0<br>     from rdiaghg : error #       818<br>     S matrix not positive definite<br> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%<br><br></div>This is how my input looks like<br><br>BEGIN<br>BEGIN_PATH_INPUT<br>&PATH<br>  restart_mode      = 'from_scratch'<br>  string_method     = 'neb',<br>  nstep_path        = 20,<br>  ds                = 2.D0,<br>  opt_scheme        = "broyden",<br>  num_of_images     = 7,<br>  k_max             = 0.3D0,<br>  k_min             = 0.2D0,<br>  CI_scheme         = "auto",<br>  path_thr          = 0.1D0,<br>/<br>END_PATH_INPUT<br>BEGIN_ENGINE_INPUT<br>&CONTROL<br>  prefix         = "TS1"<br>  outdir         = "./tmp/",<br>  pseudo_dir     = "/home/cbotchway/Cecil",<br>/<br>&SYSTEM<br>  ibrav                  = 0,<br>  nat                    = 120,<br>  ntyp                   = 5,<br>  ecutwfc                = 40.0D0,<br>  ecutrho                = 240.0D0,<br>  nspin                  = 2,<br>  starting_magnetization = 0.5D0,<br>  occupations            = "smearing",<br>  degauss                = 0.03D0,<br>/<br>&ELECTRONS<br>  conv_thr    = 1.D-6,<br>  mixing_beta = 0.2D0,<br>  electron_maxstep =1000000,<br>/<br>&IONS<br>/<br>ATOMIC_SPECIES<br>O    15.99940    O.pbe-van_ak.UPF<br>Si   28.0855    Si.pbe-n-van.UPF<br>Al   26.98154   Al.pbe-n-van.UPF<br>H     1.00794    H.pbe-van_ak.UPF<br>C    12.0107     C.pbe-van_ak.UPF<br>BEGIN_POSITIONS<br>FIRST_IMAGE<br>ATOMIC_POSITIONS (alat)<br>O        6.226694422   1.600275419   2.184924354   0 0 0<br>O       12.708816022  13.234159993   5.738093626   0 0 0<br>O       12.828127437   1.545084085   5.281812015   0 0 0<br>O       12.876343333  12.656172642   2.211401393   0 0 0<br>O        6.186293741  13.313766071   1.799333749   0 0 0<br>O        6.443594281   1.023531891   5.767275456   0 0 0<br>O        6.337219443  12.703873910   5.357337611   0 0 0<br>O       12.941217779   0.939626460   1.796223732   0 0 0<br>O       15.607357361   8.418020996   5.628934880   0 0 0<br></div>I froze the structure of the zeolite by assigning the zeros leaving just the adsorbates while increasing and decreasing the numbers of processor cores from<br></div>8-16 and still encountered the same error. Any help or advice would be appreciated.<br></div>Thank you in advance<br></div>