From chemistry-request- at -server.ccl.net Fri Jul 26 04:55:04 2002 Received: from crane2.cf.ac.uk ([131.251.0.25]) by server.ccl.net (8.11.6/8.11.0) with ESMTP id g6Q8t4r07632 for ; Fri, 26 Jul 2002 04:55:04 -0400 Received: from thor.cf.ac.uk ([131.251.0.1]) by crane2.cf.ac.uk with esmtp (Exim 3.03 #1) id 17Y0sK-0002vr-00 for CHEMISTRY-: at :-ccl.net; Fri, 26 Jul 2002 09:55:04 +0100 Received: from localhost (sacjap -8 at 8- localhost) by thor.cf.ac.uk (8.8.8/8.6.12) with ESMTP id JAA10954 for ; Fri, 26 Jul 2002 09:55:03 +0100 (BST) Date: Fri, 26 Jul 2002 09:55:03 +0100 (BST) From: Jamie Platts X-Sender: sacjap;at;thor To: CHEMISTRY # - at - # ccl.net Subject: PES scan in G98 Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Dear CCLers, When running PES scans in G98 using Opt=ModRedundant, I often get errors such as below: Iteration 99 RMS(Cart)= 0.00000107 RMS(Int)= 0.00536936 Iteration100 RMS(Cart)= 0.00000107 RMS(Int)= 0.00536908 Curvilinear step not converged. Error imposing constraints Error termination via Lnk1e in /home/colossus/jamie/g98/l103.exe. which seems to be just short of convergence. I can't see anything in the manual which might relax this criterion, or allow more iterations, so I'm a bit stuck. Does anyone have any idea how I can fix this? Am I simply using too large a step size (30 degrees in a dihedral in this case)? ---------------------------------------------------------- Jamie Platts Dept. of Chemistry Phone: +44 (0) 2920 874950 Cardiff University Email: platts ":at:" cf.ac.uk P.O. Box 912 FAX: +44 (0) 2920 874030 Cardiff CF10 3TB www.cf.ac.uk/chemy