From chemistry-request #*at*# ccl.net Wed Sep 8 03:50:23 2004 Received: from nibbel.kulnet.kuleuven.ac.be (nibbel.kulnet.kuleuven.ac.be [134.58.240.41]) by server.ccl.net (8.12.8/8.12.8) with ESMTP id i888oMnm016425 for ; Wed, 8 Sep 2004 03:50:22 -0500 Received: from localhost (localhost [127.0.0.1]) by nibbel.kulnet.kuleuven.ac.be (Postfix) with ESMTP id 457104B5D6 for ; Wed, 8 Sep 2004 10:59:59 +0200 (CEST) Received: from octavianus.kulnet.kuleuven.ac.be (octavianus.kulnet.kuleuven.ac.be [134.58.240.71]) by nibbel.kulnet.kuleuven.ac.be (Postfix) with ESMTP id DF0094B5BB for ; Wed, 8 Sep 2004 10:59:58 +0200 (CEST) Received: from agr-ccc-splash.agr.kuleuven.ac.be (dhcp-105-184.agr.kuleuven.ac.be [10.33.105.184]) by octavianus.kulnet.kuleuven.ac.be (Postfix) with ESMTP id C80EBAF098 for ; Wed, 8 Sep 2004 10:59:58 +0200 (CEST) Message-Id: <6.1.1.1.2.20040908104305.025b6630=at=u0043641.kuleuven.be> X-Sender: u0043641=at=u0043641.kuleuven.be (Unverified) X-Mailer: QUALCOMM Windows Eudora Version 6.1.1.1 Date: Wed, 08 Sep 2004 11:00:14 +0200 To: CHEMISTRY=at=ccl.net From: Eric Breynaert Subject: CCL: Good initial guess for transition metal calculations Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1"; format=flowed X-Virus-Scanned: by KULeuven Antivirus Cluster X-Spam-Status: No, hits=0.9 required=7.5 tests=MY_BAD_DOT 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 i888oNnm016429 Dear ccl'ers, What would be a good initial guess if one is doing geometry optimisations on a large range of similar transition metal structures? I'm doing ub3lyp/lanl2dz calculations on Technetium compounds. These calculations often need a very large computational effort. Improving that initial guess would probably reduce the computation time. In some literature it says to read the inital guess from a HF calculation with the same basis set. But HF seems to be a really bad method for TM-systems. Would it be possible to reuse the wavefunction for an optimised structure as starting point for a similar structure? Or would it be possible to optimise for example a Tc(OH)4 molecule or a [TcO]2+ core, and use that wavefunction as an inital guess ? thanks, Eric -- Eric Breynaert Labo voor Colloodchemie Kasteelpark Arenberg 23 B-3001 Leuven Tel: +3216321457 Fax: +3216321998