From chemistry-request(+ at +)server.ccl.net Thu Aug 30 06:02:30 2001 Received: from mel.ruc.dk ([130.225.220.27]) by server.ccl.net (8.11.0/8.11.0) with ESMTP id f7UA2TM25997 for ; Thu, 30 Aug 2001 06:02:29 -0400 Received: from smtprelay.ruc.dk (smtprelay.ruc.dk [130.225.220.22]) by mel.ruc.dk (8.9.3/8.9.1) with ESMTP id MAA00726; Thu, 30 Aug 2001 12:02:28 +0200 (MET DST) Received: from virgil.ruc.dk (virgil.ruc.dk [130.225.220.110]) by smtprelay.ruc.dk (8.9.3+Sun/8.9.3) with ESMTP id LAA19262; Thu, 30 Aug 2001 11:39:47 +0200 (MEST) Received: from VIRGIL/SpoolDir by virgil.ruc.dk (Mercury 1.44); 30 Aug 01 12:02:28 +0100 Received: from SpoolDir by VIRGIL (Mercury 1.44); 30 Aug 01 12:02:23 +0100 From: "Jens Spanget-Larsen" Organization: Roskilde Universitetscenter To: Frank Jensen , chemistry&$at$&ccl.net Date: Thu, 30 Aug 2001 12:02:00 +0100 Subject: CCL:combination of b3lyp and cc-pVQZ X-Confirm-Reading-To: "Jens Spanget-Larsen" X-pmrqc: 1 Priority: normal X-mailer: Pegasus Mail for Windows (v2.23) Message-ID: <1A38EE7A57ED%!at!%virgil.ruc.dk> Frank Jensen: > We have recently done some benchmarking of > various basis set for DFT. For the H,C,N,O,F molecules > in the G3 data set, the MAD and Maximum error of some > popular basis sets for total atomization energies > with the BLYP functional are (kJ/mol): > > MAD Max > > 6-31G* 16 64 > cc-pVDZ 41 82 > cc-pVTZ 3.6 14.5 > cc-pVQZ 2.9 10.9 > > These numbers are errors relative to a saturated basis > set, i.e. the Kohn-Sham limit. These data are interesting. Why does cc-pVDZ perform so much worse than cc-pVTZ? Is this an indication that the valence-triple-zeta extension is physically very significant, or does the cc-pVDZ basis set suffer from som particular 'unbalance'? Comparison with the relatively satisfactory 6-31G* results might suggest that something is 'wrong' with cc-pVDZ. Any similar benchmarks for Raman intensities? Jens >--< =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- JENS SPANGET-LARSEN Office: +45 4674 2710 Department of Chemistry Fax: +45 4674 3011 Roskilde University (RUC) Cell-Phone: +45 2320 6246 P.O.Box 260 E-Mail: JSL {*at*} virgil.ruc.dk DK-4000 Roskilde, Denmark http://virgil.ruc.dk/~jsl =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-