From chemistry-request@ccl.net Wed Mar 31 04:14:32 2004 Received: from linus.imcm.cas.cz (Linus.imcm.cas.cz [147.231.77.250]) by server.ccl.net (8.12.8/8.12.8) with ESMTP id i2V9EUjs016483 for ; Wed, 31 Mar 2004 04:14:31 -0500 Received: from linus.imcm.cas.cz (localhost [127.0.0.1]) by linus.imcm.cas.cz (8.12.11/8.12.11) with ESMTP id i2V9Hkkm021787; Wed, 31 Mar 2004 11:17:47 +0200 Received: from localhost (ccl@localhost) by linus.imcm.cas.cz (8.12.11/8.12.11/Submit) with ESMTP id i2V9HkAq021784; Wed, 31 Mar 2004 11:17:46 +0200 Date: Wed, 31 Mar 2004 11:17:45 +0200 (CEST) From: Petr Toman To: CHEMISTRY.-at-.ccl.net cc: bellocks.-at-.chimfarm.unipg.it Subject: CCL: SUMMARY of IRC in Gaussian 98 stops at false minimum Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Spam-Status: No, hits=0.0 required=7.0 tests=none autolearn=no version=2.61 X-Spam-Checker-Version: SpamAssassin 2.61 (1.212.2.1-2003-12-09-exp) on servernd.ccl.net Dear Colleagues, I would like to thank for all answers to my question "IRC in Gaussian 98 stops at false minimum". Final solution was tightening of the convergence criteria for the optimization in Gaussian by means of IOP(1/7) and updating force constants always after some points. The responses I received are below. Best regards, Petr Toman ******************************************************************************* ORIGINAL MESSAGE: Date: Tue, 2 Mar 2004 13:18:40 +0100 (CET) From: Petr Toman To: CHEMISTRY.-at-.ccl.net Subject: CCL:IRC in Gaussian 98 stops at false minimum Dear Colleagues, I would like to calculate the reaction path from a transition structure of a merocyanine molecule (37 atoms). Transition point was verified by a Freq calculation, imaginary frequency is 43 cm-1. The problem is that IRC calculation stops after very few points reporting "Minimum found on this side of the potential". However, usual geometry optimization (OPT) starting at this point finds the actual minimum far away. My question is what is the criterion for a minimum in Gaussian IRC calculation? Thank you for your help. Best regards, Petr Toman ******************************************************************************* Date: Tue, 2 Mar 2004 08:03:50 -0500 (EST) From: Binh Hoa Bui To: Petr Toman Subject: Re: CCL:IRC in Gaussian 98 stops at false minimum Hi Petr, Did you check the nature of the 43 cm-1 vib. mode? The structure may be a different local minimum with a rotor as indicated by the mode. You did not find the right TS, yet, i think. Sincerely, binh ******************************************************************************* Date: Tue, 2 Mar 2004 08:25:46 -0600 From: Phil Hultin To: Petr Toman Subject: RE: IRC in Gaussian 98 stops at false minimum You may have run into this problem because the force constants need updating. Unless you specify CalcAll, Gaussian will use the estimated force constants from the TS and extrapolate them to each point along the IRC. Often this works ok, but sometimes you will get into a region where this extrapolation is not good. We did not find it falling into a minimum (it may actually be a real minimum on your potential surface, by the way, just not the one you want) but we had IRC jobs fail after various numbers of points. As I recall, the solution was to do the rather slow CalcAll. It may also help to reduce the step size, because you may be jumping too far along the predicted IRC path. Dr. Philip G. Hultin Associate Department Head and Associate Professor of Chemistry University of Manitoba Winnipeg, MB, Canada R3T 2N2 (vox) 204-474-9814 (fax) 204-474-7608 mailto:hultin.-at-.cc.umanitoba.ca http://www.umanitoba.ca/chemistry/ ******************************************************************************* Date: Tue, 2 Mar 2004 08:27:36 -0800 From: Stephen Bowlus To: Petr Toman Subject: Re: CCL:IRC in Gaussian 98 stops at false minimum I don't use Gaussian, but it looks like you have located a TS that has nothing to do with the reaction you are studying. 1. Usually, a true reaction TS will give an imaginary frequency which is reasonably large - a couple hundred wave numbers. 2. Small imaginary frequencies are "trivial" wrt the reaction, but may be "real" in describing a motion like the TS for an internal rotation of a methyl group (the same types of negative roots will creep into the calculations of ground state starting materials and products). 3. Does the same thing happen if you run the IRC in the opposite direction? 4. For refining a TS, I have had to use very gentle methods like eigenvector following or Bartel's method. sb ******************************************************************************* Date: Thu, 4 Mar 2004 18:34:15 -0500 (EST) From: Cust. Service Doug Reply-To: gaussian.com!help%gaussian.com.-at-.gaussian.com To: Petr Toman Subject: Re: CCL:IRC in Gaussian 98 stops at false minimum Dr. Toman, The stopping criteria is a difficulty in this type of search. The algorithm is built around a fixed step so it does not aim to actually zero the full gradient. Rather it looks at variation in the energy and tries to check for change in sign on the gradient in case it steps past the minimum. Both of these can be tricked too easily but nothing better has been developed. Try using a smaller step and see if that lets it follow the IRC better. Note that it will generally stop far from the minimum but after computing the requested number of points along the line, 6 on each side by default. -- Douglas J. Fox Technical Support Gaussian, Inc. help.-at-.gaussian.com ******************************************************************************* From chemistry-request@ccl.net Wed Mar 31 03:24:50 2004 Received: from smail-104.hanmail.net (smail-104.hanmail.net [211.43.197.26]) by server.ccl.net (8.12.8/8.12.8) with ESMTP id i2V8Oljs013666 for ; Wed, 31 Mar 2004 03:24:48 -0500 Received: from wwl294.hanmail.net ([211.233.31.45]) by smail-104.hanmail.net (8.12.1/8.9.1) with ESMTP id i2V8Rj0n005313; Wed, 31 Mar 2004 17:27:46 +0900 Received: (from hanadmin@localhost) by wwl294.hanmail.net (8.12.9/8.9.1) id i2V8REIZ004809 for ; Wed, 31 Mar 2004 17:27:14 +0900 Content-Type: text/html; charset=euc-kr Content-Transfer-Encoding: 8bit X-Originating-IP: [166.104.203.89] From: "=?EUC-KR?B?wMy/+MHY?=" Organization: =?EUC-KR?B?x9G+57Tr?= To: Subject: CCL: calculating a large transition metal complex X-Mailer: Daum Web Mailer 1.1 Date: Wed, 31 Mar 2004 17:27:14 +0900 (KST) Message-Id: <20040331172714.HM.000000000005sNb(at)wwl294.hanmail.net> Errors-To: MIME-Version: 1.0 X-Hanmail-Attr: X-Spam-Status: No, hits=6.6 required=7.0 tests=FROM_ENDS_IN_NUMS,HTML_60_70, HTML_FONTCOLOR_UNSAFE,HTML_IMAGE_ONLY_06,HTML_MESSAGE, HTML_MIME_NO_HTML_TAG,MIME_HTML_ONLY,RCVD_IN_RFCI,WEIRD_PORT autolearn=no version=2.61 X-Spam-Level: ****** X-Spam-Checker-Version: SpamAssassin 2.61 (1.212.2.1-2003-12-09-exp) on servernd.ccl.net

Hi,

I am trying  to optimize and eventually calculate nmr shift of a large metal complex

my complex is consisted with 33 Carbon, 2 Bromide and Cobalt. However,

I can't seem to find the right method and right basis set for the calculation.

I can say that i really don't have much knowledge about calculation...

 

i've tried hf/lanl2dz and b3lyp/lanl2dz,.. but the calculation just stops..

is my complex too big for the methods that i've tried?

Thank you very much in advance

Regards,
Matt Rhee from Korea



"?l8. @NEM3], Daum" http://www.daum.net  !:Fr;}>24B 9+7a GQ8^@O3]!;
GA8.9L>v 8^@O =a:8n?d?
:|8% @|<[,Fm8.GQ 1b4I@G 3*88@G 0mG00] 8BCc 8^@O!
From chemistry-request@ccl.net Wed Mar 31 01:37:47 2004 Received: from collapsed.wormhole.hu (collapsed.wormhole.hu [195.70.35.130]) by server.ccl.net (8.12.8/8.12.8) with ESMTP id i2V6bkjs007544 for ; Wed, 31 Mar 2004 01:37:47 -0500 Received: from ta1.sednet.hu ([212.97.0.169] helo=Moon) by collapsed.wormhole.hu with asmtp (Exim 3.36 #1 (Debian)) id 1B8ZPJ-0000SG-00 for ; Wed, 31 Mar 2004 08:41:02 +0200 Received: from szilva by Moon with local (Exim 3.36 #1 (Debian)) id 1B8aOV-0000H1-00 for ; Wed, 31 Mar 2004 09:44:15 +0200 Date: Wed, 31 Mar 2004 09:44:15 +0200 From: Szilveszter Juhos To: CHEMISTRY(at)ccl.net Subject: CCL: Drugdesign.org Message-ID: <20040331074415.GB536(at)computer.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.5.1+cvs20040105i X-Spam-Status: No, hits=0.0 required=7.0 tests=none autolearn=no version=2.61 X-Spam-Checker-Version: SpamAssassin 2.61 (1.212.2.1-2003-12-09-exp) on servernd.ccl.net As far as I remember Drugdesign.org was advertised here quite a while ago. Though the link collection was not the best all over the world but was useful sometimes. Seems now it is suspended for days - is the maintainer still on the list? Nomen est omen, would be nice to keep this domain to the "drug design community" and not to pass to on-line pharmacies and similar b*5!&rds. Cheers: Szilva Return-Path: Date: Wed, 31 Mar 2004 09:09:57 -0500 From: Piotr Piecuch To: chemistry*at*ccl.net Subject: 36th Midwest Theoretical Chemistry Conference (fwd) Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-ND-MTA-Date: Wed, 31 Mar 2004 09:11:58 -0500 (EST) X-ND-Virus-Scan: engine v4.3.20; dat v4345 ========================================================================== The 36th Midwest Theoretical Chemistry Conference, East Lansing, June 17-19, 2004. Please look at: www.chemistry.msu.edu/mwtcc/mwtcc.shtml ========================================================================== Dear Colleague, The 36th Midwest Theoretical Chemistry Conference (MWTCC) will be held at Michigan State University in East Lansing, Thursday - Saturday, June 17-19, 2004. The conference web site, with all relevant details, is: http://www.chemistry.msu.edu/mwtcc/mwtcc.shtml This web site will be updated as we approach the conference. You can register for the conference and submit an abstract using the above web site. The format for the conference will be the traditional one, in which each oral session will begin with a plenary speaker, followed by contributed talks. There will be two poster sessions during the conference. The following distinguished scientists have agreed to give invited plenary talks: Professor Mark S. Gordon, Iowa State University and Ames Laboratory, Profrssor Todd J. Martinez, University of Illinois at Urbana Champaign, Professor Donald G. Truhlar, University of Minnesota, Dr. William Swope, IBM. We hope you will plan to attend the MWTCC. Please mark your calendars and please encourage your colleagues, students, and postdocs to attend as well. Early registration and abstract submission will ensure oral presentation spots. Regards, Piotr Piecuch, on behalf of the 36th MWTCC Organizing Committee