# incosistent DFT energies

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 Afdemoura Member Profile Send PM
 Just Got Here Threads 2 Posts 4
 3:13:57 PM PDT - Tue, Aug 9th 2016 Dear NWChem users and developers, I'm running some DFT calculations for a small cobalt oxide nanoparticle using CAM-B3LYP/6-31G, which ran fine in the Flux HPC cluster at the University of Michigan, using typically 48 cores. The NWChem which is installed there is version 6.1.1. Recently I got access to the new Brazilian HPC facility named SDumont, with an much larger allocation (up to 1200 cores per job), but NWChem is producing erratic energies (the NWChem version is 6.6). I have repeated the same calculation using different number of nodes from 1 node (24 cores) to 25 nodes (600 cores) and SCF energies were the same during the first few steps of each calculation, then at some point the began to diverge from each other. Final SCF energy differences are too large: bench-01.out: Total DFT energy = -25618.475583943055 bench-02.out: Total DFT energy = -25618.497788784134 bench-03.out: Total DFT energy = -25618.516200558504 bench-04.out: Total DFT energy = -25618.497025334986 bench-05.out: Total DFT energy = -25618.495954391034 bench-06.out: Total DFT energy = -25618.515982887682 bench-07.out: Total DFT energy = -25618.408124515601 bench-08.out: Total DFT energy = -25618.472081296870 bench-09.out: Total DFT energy = -25618.515687469651 (the numbers in the output name stand for the number of nodes I have used) I have repeated some of these calculations and energies were different from any previous values. here's the input I'm running: start bench-01 memory total 2500 stack 750 heap 750 global 1000 mb charge 2 geometry ```O 0.000000 2.123168 3.002613 Co 1.428727 2.020525 4.286181 O 1.283568 3.938407 4.286181 Co -0.000000 4.041050 2.857454 O -1.283568 3.938407 4.286181 Co -1.428727 2.020525 4.286181 O -0.000000 2.123168 5.569748 Co 0.000000 4.041050 -0.000000 O 0.000000 2.123168 -0.145159 Co 1.428727 2.020525 -1.428727 O 0.000001 2.123168 -2.712295 Co -1.428727 2.020525 -1.428727 O -1.573885 0.102642 -1.428728 Co -2.857454 -0.000000 -0.000000 O -2.857454 -1.917882 0.145159 Co -1.428727 -2.020525 1.428727 O -0.000001 -2.123168 2.712295 Co 1.428727 -2.020525 1.428728 O 1.573886 -0.102643 1.428728 Co 2.857454 0.000000 2.857455 O 4.141022 -0.102643 1.428728 Co 2.857454 -0.000000 0.000001 O 2.857454 1.917882 -0.145158 Co 2.857453 3.030787 1.428728 O 1.283569 4.143692 1.428726 O 2.857452 1.917884 3.002614 O 2.857454 -1.917882 0.145160 O 1.573886 0.102642 -1.428727 Co 0.000001 -1.010262 -1.428725 O 0.000002 -2.123167 0.145159 Co -2.857454 0.000000 2.857454 O -1.573886 -0.102643 1.428727 Co -0.000000 1.010262 1.428726 O -4.141022 -0.102643 1.428726 O -2.857454 1.917882 -0.145160 Co -2.857453 3.030787 1.428726 O -2.857454 1.917882 3.002611 O -1.283568 4.143691 1.428727 O -1.283568 3.938407 -1.428727 O 2.857453 -1.917882 2.712296 O -2.857455 -1.917882 2.712295 O 1.283568 3.938407 -1.428727 O 1.573884 0.102642 4.286181 Co -0.000001 -1.010262 4.286180 O -1.573885 0.102643 4.286180 H 4.641131 0.704307 1.463704 H 2.554397 -2.246781 -0.692982 H 2.519420 -2.296244 3.515462 H -2.554397 -2.246781 3.550437 H -2.519420 -2.296244 -0.658007 H -4.641131 0.704307 1.393751 H 0.034976 1.316218 6.069856 H 2.086734 4.316769 3.948148 H -2.121710 4.267306 3.983123 H 2.121710 4.267305 -1.125670 H -2.086734 4.316769 -1.090694 H -0.034975 1.316218 -3.212404 ``` end basis "ao basis" spherical ```* library 6-31G ``` end basis "cd basis" spherical ```* library "Ahlrichs Coulomb Fitting" ``` end dft ```mult 16 iterations 1000 convergence energy 1e-6 xc xcamb88 1.00 lyp 0.81 vwn_5 0.19 hfexch 1.00 cam 0.33 cam_alpha 0.19 cam_beta 0.46 grid fine tolerances accqrad 20 ``` end task dft energy Any ideas where to begin? Thanks! Andre

 Sean bureaucrat Profile Send PM
 Gets Around Threads 1 Posts 153
 5:25:53 AM PDT - Wed, Aug 10th 2016 Do the 2nd Co and 22nd O actually have y and z coordinates or was there a mistake in copying your input file to the post?

 Afdemoura Member Profile Send PM
 Just Got Here Threads 2 Posts 4
 5:48:53 AM PDT - Wed, Aug 10th 2016 Quote:Sean Aug 10th 5:25 amDo the 2nd Co and 22nd O actually have y and z coordinates or was there a mistake in copying your input file to the post? Hi Sean, it is a copy-and-paste error, they have coordinates (calculation runs fine in the older HPC allocation). Andre

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