From owner-nwchem-users@emsl.pnl.gov Wed Feb 14 08:51:17 2007 Received: from odyssey.emsl.pnl.gov (localhost [127.0.0.1]) by odyssey.emsl.pnl.gov (8.13.8/8.13.8) with ESMTP id l1EGpGlt018296 for ; Wed, 14 Feb 2007 08:51:17 -0800 (PST) Received: (from majordom@localhost) by odyssey.emsl.pnl.gov (8.13.8/8.13.8/Submit) id l1EGpGOB018295 for nwchem-users-outgoing-0915; Wed, 14 Feb 2007 08:51:16 -0800 (PST) X-Authentication-Warning: odyssey.emsl.pnl.gov: majordom set sender to owner-nwchem-users@emsl.pnl.gov using -f X-Ironport-SG: OK_Domains X-Ironport-SBRS: 4.7 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AgAAAMLM0kWGVHcGk2dsb2JhbACOYQEBBw4HBh2STQEBAQ X-IronPort-AV: i="4.14,169,1170662400"; d="scan'208"; a="13545523:sNHT18882990" X-Umn-Remote-Mta: [N] user-38q46j5.cable.mindspring.com [209.162.26.101] #+TS+AU+HN Mime-Version: 1.0 (Apple Message framework v752.2) In-Reply-To: <744517.58692.qm@web58902.mail.re1.yahoo.com> References: <744517.58692.qm@web58902.mail.re1.yahoo.com> Content-Type: text/plain; charset=WINDOWS-1252; delsp=yes; format=flowed Message-Id: <8212F296-B1ED-4F83-9C5F-89C56EC610E5@umn.edu> From: "Donald G. Truhlar" Subject: Re: [NWCHEM] M05-2X Date: Wed, 14 Feb 2007 10:50:58 -0600 To: users nwchem X-Mailer: Apple Mail (2.752.2) Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by odyssey.emsl.pnl.gov id l1EGpFNC018292 Sender: owner-nwchem-users@emsl.pnl.gov Precedence: bulk I agree with some recent comments on density functionals, in particular that many density functionals become inaccurate for larger systems and are inappropriate for noncovalent interactions. I note, however, that many of the problems with older DFT functionals have been greatly alleviated and even eliminated by the recent M05-2X functional. In particular M05-2X does much better than previous functionals on retaining its accuracy for larger systems, and it gives excellent results for noncovalent interactions at distances important for van der Waals molecules and for conformational analysis. The following references are relevant to these points: "Design of Density Functionals by Combining the Method of Constraint Satisfaction with Parametrization for Thermochemistry, Thermochemical Kinetics, and Noncovalent Interactions," Y. Zhao, N. E. Schultz, and D. G. Truhlar, Journal of Chemical Theory and Computation 2, 364-382 (2006). "Comparative DFT Study of van der Waals Complexes: Rare-Gas Dimers, Alkaline-Earth Dimers, Zinc Dimer, and Zinc-Rare-Gas Dimers," Y. Zhao and D. G. Truhlar, Journal of Physical Chemistry A 100, 5121-5129 (2006). "Assessment of Model Chemistries for Noncovalent Interactions," Y. Zhao and D. G. Truhlar, Journal of Chemical Theory and Computation 2, 1009-1018 (2006). “Density Functionals for Noncovalent Interaction Energies of Biological Importance,” Y. Zhao and D. G. Truhlar, Journal of Chemical Theory and Computation 3, 289-300 (2007). Assessment of Density Functionals for Pi Systems: Energy Differences Between Cumulenes and Poly-ynes and Proton Affinities, Bond Length Alternation, and Torsional Potentials of bimoleculgated Polyenes, and Proton Affinities of Conjugated Schiff Bases,” Y. Zhao and D. G. Truhlar, Journal of Physical Chemistry A 110, 10478-10486 (2006). "Representative Benchmark Suites for Barrier Heights of Diverse Reaction Types and Assessment of Electronic Structure Methods for Thermochemical Kinetics," J. Zheng, Y. Zhao, and D. G. Truhlar, Journal of Chemical Theory and Computation, in press. (available in ASAP) "How Well Can New-Generation Density Functional Methods Describe Protonated Epoxides Where Older Functionals Fail?" Y. Zhao and D. G. Truhlar, Journal of Organic Chemistry 72, 295-298 (2007). "A Density Functional Theory that Accounts for Medium-Range Correlation Energies in Organic Chemistry," Y. Zhao and D. G. Truhlar, Organic Letters 8, 5753-5755 (2006). "Computational Requirements for Simulating the Structures and Proton Activity of Silicaceous Materials." Zhang, Y.; Li, Z. H.; Truhlar, D. G. Journal of Chemical Theory and Computation, in press. (available in ASAP) NWChem is the first computer package to release the M05-2X functional. Don Truhlar ************************************************************************ **** Donald G. Truhlar truhlar@umn.edu [editorial: editor@chem.umn.edu] http://comp.chem.umn.edu/Truhlar Regents Professor of Chemistry, Chemical Physics, Nanoparticle Science and Engineering, and Scientific Computation Department of Chemistry, University of Minnesota, 207 Pleasant St. SE, Minneapolis, MN 55455 Phone 612-624-7555 Fax 612-626-93900 Secretary: Flurnia Hadley-Davis (davis@chem.umn.edu) ************************************************************************ *** On Feb 14, 2007, at 9:08 AM, Francesco Pietra wrote: > --- "Dixon, David" wrote: > >> One should be careful about all DFT energies. The >> errors tend to be >> random and not good to better than +/- 5 kcal/mol >> for relative energies. > > This confirms my problems. > >> Total atomization energies are completely different. > > What I am also experiencing. Though, working with > natural products without repeating units, as I do, > molecules of 50 atoms are small molecules, and total > atomizations becomes easily problematic. Especially if > one is involved with conformations, where deltaE may > be <1 kcal/mol, if one wants to check, before > attacking the problems of experimentally > unapproachable conformers. What I am used to do, is > MP2 single-point energy on dft geometry optimized. > > >> I am not talking >> about this functional specifically but all DFT >> functionals in general. >> It also depends if non-bonding interactions are >> important. > > Non bonding interactions are commonplace with natural > products. > >> DFT is known >> to get worse the larger the system. > > See above. > > A question too: What about Car-Parrinello for the > problems I alluded to above? En plus: Car_Parrinello > through pseudopotential plane waves? > > See above. >> >> David >> David A Dixon >> Robert Ramsay Chair >> >> -----Original Message----- >> From: owner-nwchem-users@emsl.pnl.gov >> [mailto:owner-nwchem-users@emsl.pnl.gov] On Behalf >> Of Francesco Pietra >> Sent: Wednesday, February 14, 2007 1:18 AM >> To: users nwchem >> Subject: [NWCHEM] m05-2x energies at minimum basis >> set >> >> Is it any experience about the reliability of dft >> energies for small (50 first-row atoms) and large >> (100 >> first-row atoms) closed-shell geometry-optimized >> molecules at what was suggested as the minimum basis >> set (6-31+G*) for the m05-2x functional? >> >> Thanks >> francesco pietra >> >> >> >> > ______________________________________________________________________ > __ >> ____________ >> Do you Yahoo!? >> Everyone is raving about the all-new Yahoo! Mail >> beta. >> http://new.mail.yahoo.com >> >> > > > > > ______________________________________________________________________ > ______________ > Expecting? Get great news right away with email Auto-Check. > Try the Yahoo! Mail Beta. > http://advision.webevents.yahoo.com/mailbeta/newmail_tools.html