Hi,<div> I used same functional (BLYP + D) and same Poisson solver, but different PP (Troullier-Martins). I will check with Goedecker PP.</div> <div> </div><div> </div><div>Regards,</div> <div> </div><div>Sandeep</div><div>1</div> <div> </div><div> <div class="gmail_quote">On Wed, Jul 4, 2012 at 1:45 PM, <<a href="mailto:hut...@pci.uzh.ch" target="_blank">hut...@pci.uzh.ch</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi Maybe you should really use exactly the same setup (Basis and Functional using GAPW) as a starting point and then step for step introduce pseudopotentials and other basis sets and e.g. dispersion corrections. The comparision with CPMD has been done with the same PP and functionals (BLYP+D2), and Poisson solver? If yes, this would point towards a basis set problem. Juerg -------------------------------------------------------------- Juerg Hutter Phone : ++41 44 635 4491 Physical Chemistry Institute FAX : ++41 44 635 6838 University of Zurich E-mail: <a href="mailto:hut...@pci.uzh.ch">hut...@pci.uzh.ch</a> Winterthurerstrasse 190 CH-8057 Zurich, Switzerland --------------------------------------------------------------- -----<a href="mailto:cp...@googlegroups.com">cp...@googlegroups.com</a> wrote: ----- To: <a href="mailto:cp...@googlegroups.com">cp...@googlegroups.com</a> From: Sandeep Kumar Reddy Sent by: <a href="mailto:cp...@googlegroups.com">cp...@googlegroups.com</a> Date: 07/02/2012 03:13PM Subject: [CP2K:3886] high binding energy <div><div class="h5"> Dear all, I want to calculate binding energy and compare with Gaussian's result and then i would like to proceed to bulk simulations. My system one ion pair (it's an ionic liquid). I did geometry optimizations of cation, anion and ion-pair and calculated the binding energy. This value is equal to -119 kcal/mol. After adding BSSE corrections, it is reduced to -116 kcal/mol. For comparison, i carried out same calculations at MP2/aug-cc-pVDZ level using Gaussian package and this value is equal to -104 kcal/mol (BSSE corrected). A difference of 10 kcal/mol of such calculation is discouraging. (I have used same functional, cell parameters, cutoff, potentials for all three calculations) I repeated the calculations by changing cutoff (to 480 Ry) and increasing box length (20 \AA). But it gives me same binding energy. Additionally, i have done same calculations in plane wave basis set using CPMD code. It gives 105 kcal/mol, very close to MP2 result. I am not able to figure out why it happens. Could anybody comment on my input files ? Ion-pair : &GLOBAL PROJECT dimethyl_ammonium_bromide RUN_TYPE GEO_OPT PRINT_LEVEL MEDIUM &END GLOBAL &FORCE_EVAL METHOD Quickstep &DFT BASIS_SET_FILE_NAME /panfs/home/Xsreddy/cp2k/tests/QS/BASIS_MOLOPT POTENTIAL_FILE_NAME /panfs/home/Xsreddy/cp2k/tests/QS/POTENTIAL &MGRID CUTOFF 280 NGRIDS 5 &END MGRID &QS METHOD GPW EPS_DEFAULT 1.0E-10 &END QS &SCF MAX_SCF 50 EPS_SCF 1.0E-6 SCF_GUESS ATOMIC &OT ON MINIMIZER CG PRECONDITIONER FULL_ALL ENERGY_GAP 0.001 &END OT &OUTER_SCF MAX_SCF 100 EPS_SCF 1.0E-6 &END OUTER_SCF &END SCF &XC &XC_FUNCTIONAL BLYP &END XC_FUNCTIONAL &vdW_POTENTIAL DISPERSION_FUNCTIONAL PAIR_POTENTIAL &PAIR_POTENTIAL TYPE DFTD2 REFERENCE_FUNCTIONAL BLYP &END PAIR_POTENTIAL &END vdW_POTENTIAL &END XC &POISSON POISSON_SOLVER WAVELET PERIODIC NONE &END POISSON &END DFT &SUBSYS &CELL ABC 20.0 20.0 20.0 PERIODIC NONE &END CELL &COORD H 1.82622900 0.00011700 1.45609900 H 0.41368700 -0.00011700 0.43855600 N 1.53927100 0.00002300 0.47861600 C 1.97625500 -1.24136700 -0.20041700 H 3.06445100 -1.28419200 -0.25417500 H 1.58040100 -2.09266400 0.34985900 H 1.53907000 -1.23367800 -1.19754500 C 1.97589400 1.24149000 -0.20039300 H 1.54099200 1.23242900 -1.19850300 H 1.57755100 2.09264100 0.34831700 H 3.06414500 1.28582600 -0.25177600 Br -1.40269500 -0.00003600 -0.01818000 &END COORD &TOPOLOGY &CENTER_COORDINATES &END &END &KIND H BASIS_SET DZVP-MOLOPT-GTH POTENTIAL GTH-BLYP-q1 &END KIND &KIND C BASIS_SET DZVP-MOLOPT-GTH POTENTIAL GTH-BLYP-q4 &END KIND &KIND N BASIS_SET DZVP-MOLOPT-GTH POTENTIAL GTH-BLYP-q5 &END KIND &KIND Br BASIS_SET DZVP-MOLOPT-SR-GTH POTENTIAL GTH-BLYP-q7 &END KIND &END SUBSYS &END FORCE_EVAL &MOTION &GEO_OPT MAX_FORCE 0.0001 MAX_ITER 500 OPTIMIZER BFGS &END GEO_OPT &END MOTION Other input files are enclosed. Thanks. Regards, Sandeep </div></div><div class="im"> -- You received this message because you are subscribed to the Google Groups "cp2k" group. </div><div class="im"> To post to this group, send email to <a href="mailto:cp...@googlegroups.com">cp...@googlegroups.com</a>. To unsubscribe from this group, send email to <a href="mailto:cp2k%2Bun...@googlegroups.com">cp2k+uns...@googlegroups.com</a>. 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