From chemistry-request(+ at +)server.ccl.net Fri Aug 30 04:25:57 2002 Received: from ns1.tudelft.nl ([130.161.180.1]) by server.ccl.net (8.11.6/8.11.0) with ESMTP id g7U8Pvr07108 for ; Fri, 30 Aug 2002 04:25:57 -0400 Received: from CONVERSION-DAEMON.mailhost2.tudelft.nl by mailhost2.tudelft.nl (PMDF V6.1-1 #40925) id <0H1N00101E2YJ9 "-at-" mailhost2.tudelft.nl> for chemistry.,at,.ccl.net; Fri, 30 Aug 2002 10:25:48 +0200 (MEST) Received: from listserv.tudelft.nl (listserv.tudelft.nl [130.161.180.33]) by mailhost2.tudelft.nl (PMDF V6.1-1 #40925) with ESMTP id <0H1N008MAE2YRS |-at-| mailhost2.tudelft.nl> for chemistry |-at-| ccl.net; Fri, 30 Aug 2002 10:25:46 +0200 (MEST) Received: from stm-ltc2.dct.tudelft.nl (stm-ltc2.dct.tudelft.nl [130.161.196.198]) by listserv.tudelft.nl (8.12.5/8.12.5) with ESMTP id g7U8Pkp2002345 for ; Fri, 30 Aug 2002 10:25:46 +0200 (MEST) Received: from STM-LTC2/SpoolDir by stm-ltc2.dct.tudelft.nl (Mercury 1.47) ; Fri, 30 Aug 2002 10:25:46 +0000 (MET-1MEST) Received: from SpoolDir by STM-LTC2 (Mercury 1.47); Fri, 30 Aug 2002 10:25:40 +0000 (MET-1MEST) Date: Fri, 30 Aug 2002 10:25:39 +0200 From: Martijn Zwijnenburg Subject: G98 and SCRF To: chemistry ^at^ ccl.net Message-id: <3D6F481F.23899.E229C836#* at *#localhost> MIME-version: 1.0 X-Mailer: Pegasus Mail for Win32 (v3.12c) Content-type: text/plain; charset=US-ASCII Content-transfer-encoding: 7BIT Priority: normal Hi, I'm trying to optimize the structure of a simple silica compund (H3SiOH) in THF solvent by means of SCRF calculation in Gaussian 98. When I run the calculation with opt=(loose) and SCRF=(cpcm,solvent=THF) the calculation converges in a couple of steps. However, when I run the calculation with the standard convergence criteria (or tighter) the calculation does never converge. The energy remains oscilating (typically in the second decimal), as does the force and displacements, and the calculation typically exits with a L9999 error. Increasing the maximum number of steps only causes the calculation to stop after more steps and not the job to converge. In both job files G98 warnes that sometimes some elements are discarded. However, only in the tighter criteria run there are warning that a certain electronic charge (in this case charge 144) has positive or a negative charge ("Electronic charge 144 has a negative value: -0.349460"). Could this screw up convergence or are there other important details wich are important to insure convergence in such SCRF calculations. Cheers, Martijn ------------------------------------------------------------------------- Martijn Zwijnenburg Lab. of Applied Organic Chemistry and Catalysis Delft University of Technology Julianalaan 136 2628 BL Delft The Netherlands Tel: 0031-(0)152782691 Fax: 0031-(0)152784700 e-mail: M.A.Zwijnenburg /at\tnw.tudelft.nl web page: http://come.to/tock