From chemistry-request -x- at -x- ccl.net Wed Aug 11 12:02:41 2004 Received: from smtpgw.sud-chemieinc.com (smtpgw.sud-chemieinc.com [208.23.162.5]) by server.ccl.net (8.12.8/8.12.8) with ESMTP id i7BH2cJH017488 for ; Wed, 11 Aug 2004 12:02:39 -0500 Received: from localhost (smtpgw.sud-chemieinc.com [127.0.0.1]) by localhost.sud-chemieinc.com (Postfix) with ESMTP id D3D1A47EA6; Wed, 11 Aug 2004 13:09:06 -0400 (EDT) Received: from smtpgw.sud-chemieinc.com ([127.0.0.1]) by localhost (smtpgw.sud-chemieinc.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 05182-06; Wed, 11 Aug 2004 13:08:59 -0400 (EDT) Received: from srvkyec1.americas.sc-world.com (srvkyec1.americas.sc-world.com [10.16.100.11]) by smtpgw.sud-chemieinc.com (Postfix) with ESMTP id 7D21547F1F; Wed, 11 Aug 2004 13:08:59 -0400 (EDT) Received: from srvkyem1.americas.sc-world.com ([10.16.100.68]) by srvkyec1.americas.sc-world.com with Microsoft SMTPSVC(5.0.2195.6713); Wed, 11 Aug 2004 13:08:59 -0400 content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" X-MimeOLE: Produced By Microsoft Exchange V6.0.6556.0 Subject: RE: G03 optimization failure Date: Wed, 11 Aug 2004 13:08:58 -0400 Message-ID: <9DD56492790889439F731F5BD6DACA0007D78957=at=srvkyem1.americas.sc-world.com> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: G03 optimization failure Thread-Index: AcR/v49ZuEMYJHPoRQ2Ie4sU8os6TQABJT4A From: "Shobe, David" To: "Jim Pfaendtner" , X-OriginalArrivalTime: 11 Aug 2004 17:08:59.0221 (UTC) FILETIME=[E481C050:01C47FC5] X-Spam-Status: No, hits=3.0 required=7.5 tests=NO_RDNS2 autolearn=no version=2.61 X-Spam-Checker-Version: SpamAssassin 2.61 (1.212.2.1-2003-12-09-exp) on servernd.ccl.net Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by server.ccl.net id i7BH2fJH017494 Jim, Some suggestions: 1. Check the final geometry of the optimization in your favorite viewer. Perhaps something unexpected has happened, such as the molecule breaking up into two fragments. 2. If the geometry is OK try using "geom=check opt=calcfc". This will fix any problems related to the Hessian (2nd derivative matrix). 3. If your radical has symmetry, try breaking the symmetry (usually this can be done by changing a torsion angle by 5-10 degrees) and reoptimizing. Hope this helps, --David Shobe, Ph.D., M.L.S. S|d-Chemie, Inc. phone (502) 634-7409 fax (502) 634-7724 Don't bother flaming me: I'm behind a firewall. -----Original Message----- From: Computational Chemistry List [mailto:chemistry-request=at=ccl.net]On Behalf Of Jim Pfaendtner Sent: Wednesday, August 11, 2004 10:49 AM To: chemistry=at=ccl.net Subject: CCL:G03 optimization failure Hi, I'm trying a simple geometry optimization in G03 , it is a C4 hydrocarbon with a carbonyl group and peroxy radical. I'm using ub3lyp/6-31g* The thing runs for awhile and then I get this error message: Linear equations converged to 1.310D-10 1.310D-09 after 10 iterations. Search did not lower the energy significantly. No lower point found -- try reversing direction. Search did not lower the energy significantly. No lower point found -- switch to scaled steepest descent. Search did not lower the energy significantly. Scaled steepest descent with Shift=0.000 failed. Search did not lower the energy significantly. Scaled steepest descent with Shift=0.025 failed. Search did not lower the energy significantly. Scaled steepest descent with Shift=0.050 failed. Search did not lower the energy significantly. Scaled steepest descent with Shift=0.075 failed. Search did not lower the energy significantly. No lower point found -- switch to steepest descent. Search did not lower the energy significantly. No lower point found -- run aborted. I have tried with and without SCF(qc) but that didn't help. Do I need to change my tolerances? I also tried to first optimize using HF and a smaller basis set to get a guess for the geometry. Thanks! -= This is automatically added to each message by the mailing script =- To send e-mail to subscribers of CCL put the string CCL: on your Subject: line and send your message to: CHEMISTRY=at=ccl.net Send your subscription/unsubscription requests to: CHEMISTRY-REQUEST=at=ccl.net HOME Page: http://www.ccl.net | Jobs Page: http://www.ccl.net/jobs If your mail is bouncing from CCL.NET domain send it to the maintainer: Jan Labanowski, jlabanow=at=nd.edu (read about it on CCL Home Page) -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+