<div dir="ltr">Hi,<div><br></div><div>I think the probable cause is the MT Poisson solver - it needs box length 2x the maximum distance between electron density in any given direction - so for your box you can only safely go out to ~10 A. </div><div><br></div><div>Probably your actual binding curve is at the smaller distance, but you can't see it for the huge noise from the spurious results at long distance.</div><div><br></div><div>Matt<br><br>On Thursday, May 1, 2014 4:02:44 AM UTC+1, August Melcher wrote:<blockquote class="gmail_quote" style="margin: 0;margin-left: 0.8ex;border-left: 1px #ccc solid;padding-left: 1ex;"><div dir="ltr">I'm working on producing a neon dimer potential energy curve, and I keep getting results that look like this. I don't seem to understand how coordinates work because I keep seeing the binding part of the curve at what I expected to be the largest separation. Here is a sample input of what I thought would be a 1.5A separation. The difference in the x coordinates is increased correspondingly for the rest of the points. See attached for what the curve looks like.<div><br><div><div>&FORCE_EVAL</div></div></div></div></blockquote><div> </div><blockquote class="gmail_quote" style="margin: 0;margin-left: 0.8ex;border-left: 1px #ccc solid;padding-left: 1ex;"><div dir="ltr"><div><div><div> METHOD Quickstep</div><div> &DFT</div><div> BASIS_SET_FILE_NAME /global/u1/a/amelcher/soft/<wbr>cp2k/cp2k/tests/QS/EMSL_BASIS_<wbr>SETS</div><div> POTENTIAL_FILE_NAME /global/u1/a/amelcher/soft/<wbr>cp2k/cp2k/tests/QS/POTENTIAL</div><div> &MGRID</div><div> CUTOFF 1000</div><div> NGRIDS 5</div><div> REL_CUTOFF 50</div><div> &END MGRID</div><div> &QS</div><div> METHOD GAPW</div><div> EPS_PGF_ORB 1.0E-12</div><div> EPS_FILTER_MATRIX 0.0e0</div><div> &END QS</div><div> &POISSON</div><div> PERIODIC NONE</div><div> PSOLVER MT</div><div> &END</div><div> &SCF</div><div> EPS_SCF 1.0E-8</div><div> SCF_GUESS ATOMIC</div><div> MAX_SCF 40</div><div> &OUTER_SCF</div><div> EPS_SCF 1.0E-8</div><div> MAX_SCF 50</div><div> &END OUTER_SCF</div><div> &OT ON</div><div> &END</div><div> &END SCF</div><div> &XC</div><div> &XC_FUNCTIONAL</div><div> &BECKE97</div><div> PARAMETRIZATION wB97X-V</div><div> SCALE_X 1.0</div><div> SCALE_C 1.0</div><div> &END</div><div> &END XC_FUNCTIONAL</div><div> &HF</div><div> &SCREENING</div><div> EPS_SCHWARZ 1.0E-14</div><div> &END</div><div> &INTERACTION_POTENTIAL</div><div> POTENTIAL_TYPE MIX_CL</div><div> SCALE_COULOMB 0.833</div><div> SCALE_LONGRANGE 0.167</div><div> OMEGA 0.30</div><div> &END</div><div> &MEMORY</div><div> MAX_MEMORY 128</div><div> &END</div><div> #FRACTION 0.167</div><div> &END</div><div> &vdW_POTENTIAL</div><div> DISPERSION_FUNCTIONAL NON_LOCAL</div><div> &NON_LOCAL</div><div> TYPE RVV10</div><div> PARAMETERS 6.3 0.0093</div><div> VERBOSE_OUTPUT</div><div> KERNEL_FILE_NAME /global/u1/a/amelcher/soft/<wbr>cp2k/cp2k/tests/QS/rVV10_<wbr>kernel_table.dat</div><div> CUTOFF 80</div><div> &END NON_LOCAL</div><div> &END vdW_POTENTIAL</div><div> &END XC</div><div> &END DFT</div><div> &SUBSYS</div><div> &CELL</div><div> ABC 20.0 15.0 15.0</div><div> PERIODIC NONE</div><div> &END CELL</div><div> &COORD</div><div>Ne 13.25 0.0000 0.0000</div><div>Ne 11.75 0.0000 0.0000</div><div> &END COORD</div><div> &KIND Ne</div><div> BASIS_SET aug-cc-pVQZ</div><div> LEBEDEV_GRID 590</div><div> RADIAL_GRID 250</div><div> POTENTIAL ALL</div><div> &END KIND</div><div> &END SUBSYS</div><div>&END FORCE_EVAL</div><div>&GLOBAL</div><div> PROJECT wb97xv15</div><div> PRINT_LEVEL LOW</div><div> RUN_TYPE ENERGY</div><div> &TIMINGS</div><div> THRESHOLD 0.000000001</div><div> &END</div><div>&END GLOBAL</div></div><div><br></div></div></div></blockquote></div></div>