From chemistry-request@server.ccl.net Thu Dec 9 03:32:36 1999 Received: from darwin.ntu.edu.au (darwin.ntu.edu.au [138.80.128.3]) by server.ccl.net (8.8.7/8.8.7) with SMTP id DAA05256 for ; Thu, 9 Dec 1999 03:32:33 -0500 Received: (qmail 4720 invoked from network); 9 Dec 1999 07:23:17 -0000 Received: from quoll.ntu.edu.au (138.80.63.13) by darwin.ntu.edu.au with SMTP; 9 Dec 1999 07:23:17 -0000 Received: by quoll.ntu.edu.au; (5.65/1.1.8.2/09Aug94-1121AM) id AA29224; Thu, 9 Dec 1999 17:13:40 +0930 Date: Thu, 9 Dec 1999 17:13:39 +0930 From: Brian Salter-Duke To: chemistry@ccl.net Subject: CBS methods in G98 Message-Id: <19991209171339.A29133@quoll.ntu.edu.au> Mail-Followup-To: chemistry@ccl.net Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.95.6i The CBS methods in G98 differ slightly from those in G94. In addition to using the Minimal Population Localization procedure, CBS-4, called as CBS-4M as opposed to CBS-4O, gives a different parameterisation of the 2-electron term in the empirical correction. From the code it uses 5.98 in place of 5.52. Ok, this seems fine and dandy, but where in the literature is this reported? I can find no reference to this new parameter value. Can anyone point me to a reference for it? Mnay thanks. Cheers, Brian. -- Associate Professor Brian Salter-Duke (Brian Duke) Chemistry, Faculty of Science, IT and Education, Northern Territory University, Darwin, NT 0909, Australia. Phone (61) (0)8-89466702 e-mail: b_duke@lacebark.ntu.edu.au or b_duke@quoll.ntu.edu.au From chemistry-request@server.ccl.net Thu Dec 9 05:50:25 1999 Received: from fg702-6.abct.polyu.edu.hk (fg702-6.abct.polyu.edu.hk [158.132.74.201]) by server.ccl.net (8.8.7/8.8.7) with ESMTP id FAA06057 for ; Thu, 9 Dec 1999 05:50:23 -0500 Received: from fg702-6.abct.polyu.edu.hk (dannt.polyu.edu.hk [158.132.31.49]) by fg702-6.abct.polyu.edu.hk (8.8.8/8.8.8) with ESMTP id RAA40530 for ; Thu, 9 Dec 1999 17:45:58 +0800 (HKT) Message-ID: <384F7845.16011ECF@fg702-6.abct.polyu.edu.hk> Date: Thu, 09 Dec 1999 17:37:09 +0800 From: Daniel Mok X-Mailer: Mozilla 4.61 [en] (Win98; I) X-Accept-Language: en,zh-TW,zh-CN MIME-Version: 1.0 To: CCL Subject: Program for fitting potential surface? Content-Type: text/plain; charset=big5 Content-Transfer-Encoding: 7bit Hi, I wonder is there any program that can determined the coefficient of a potential surface by a least-squares to a number of ab initio single point energies. It is even better if such a code is in public domain. Thanks for any suggestion. Daniel -- Office: (852)-2766 5629 Fax: (852)-2364 9932 Department of Applied Biology and Chemical Technology The Hong Kong Polytechnic University. From chemistry-request@server.ccl.net Thu Dec 9 12:40:31 1999 Received: from picasso.chem.uab.edu (picasso.chem.uab.edu [138.26.72.15]) by server.ccl.net (8.8.7/8.8.7) with ESMTP id MAA08509 for ; Thu, 9 Dec 1999 12:40:31 -0500 Received: from picasso (localhost [127.0.0.1]) by picasso.chem.uab.edu (AIX4.2/UCB 8.7/8.7) with SMTP id KAA18080 for ; Thu, 9 Dec 1999 10:32:48 -0600 (CST) Sender: naga@picasso.chem.uab.edu Message-ID: <384FD9B0.41C6@picasso.chem.uab.edu> Date: Thu, 09 Dec 1999 10:32:48 -0600 From: "Gantasala N. Srinivas" X-Mailer: Mozilla 3.0Gold (X11; I; AIX 2) MIME-Version: 1.0 To: CHEMISTRY@ccl.net Subject: ECP on transition metals Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Dear CCL, Can some one please suggest me the recent review articles on ECPs for transition metals. Thank you -Srinivas -- From chemistry-request@server.ccl.net Thu Dec 9 14:22:24 1999 Received: from org.chem.msu.su (org.chem.msu.su [158.250.32.94]) by server.ccl.net (8.8.7/8.8.7) with ESMTP id OAA09079 for ; Thu, 9 Dec 1999 14:22:18 -0500 Received: from localhost (serge@localhost) by org.chem.msu.su (8.9.3/8.9.3) with ESMTP id VAA04385 for ; Thu, 9 Dec 1999 21:12:57 +0300 (MSK) Date: Thu, 9 Dec 1999 21:12:56 +0300 (MSK) From: Serge Pissarev To: Computational Chemistry List Subject: Structure question Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Dear CCLers, Could anybody share to me the latest known references concerning the structural studies on the 1-acylpiperidine (formyl-, acetyl-, etc) molecules (structure, inversion/rotation barriers), computational or experimental? Any hints are greatly appreciated... Thank you in advance Serge ---| Serge A. Pisarev Chemistry Department of Moscow State University. From chemistry-request@server.ccl.net Thu Dec 9 18:37:44 1999 Received: from darkwing.uoregon.edu (genghis@darkwing.uoregon.edu [128.223.142.13]) by server.ccl.net (8.8.7/8.8.7) with ESMTP id SAA11074 for ; Thu, 9 Dec 1999 18:37:44 -0500 Received: from localhost (genghis@localhost) by darkwing.uoregon.edu (8.9.3/8.9.3) with SMTP id OAA08750 for ; Thu, 9 Dec 1999 14:28:27 -0800 (PST) Date: Thu, 9 Dec 1999 14:28:27 -0800 (PST) From: "Dale A. Braden" To: cclpost Subject: NBO vs AIM Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Dear CCL, I would like to solicit opinions about the relative merits and demerits of using the natural bond orbital (NBO) method of population analysis versus the atoms-in-molecules (AIM) method. We reported both quantities in a paper, leaving it to the reader's preference, and found ourselves in the delightful position of being told by one reviewer that NBO is not reliable and to use AIM only, and the other of whom said not to trust AIM, but stick with NBO. Catch-22. As I understand it, the main argument against NBO is that against any orbital-based method: orbital-based methods leave artifacts because the occupancies of diffuse orbitals are weighted towards the atom on which they are centered. Another argument is that an NBO analysis is based on the best localized set of orbitals for the molecule, and if the molecule is in fact very delocalized, then the NBO results may not be very sensible. At least one argument against AIM is that it often gives larger values of atomic charges (+ or -) for atoms connected by bonds that are expected to be covalent. I also understand that there is no right answer to the contrived problem of population analysis, but I would like to hear opinions from those who have made or seen lots of comparisons between these methods. For what it's worth, and to help provoke responses, I think AIM makes more sense for quantifying the total charge or spin around a nucleus, and if the total wave function describes the kind of charge distribution seen in an X-ray diffraction experiment, then an AIM analysis would be the way to break it up into atomic contributions, and the unobservable orbitals need not be considered. If AIM charges are not what is expected, then it could be a sign that AIM is not reliable, or it could equally well be a sign that traditional notions of covalency/ionicity are in need of revision. If AIM describes ethane (in broken symmetry) as an ionic species (CH3-, CH3+), then I will change my mind. What do you think? I will certainly summarize the arguments for and against each method. If you want anonymity (to avoid flame wars), respond to me personally, because I will just summarize the arguments pro and con, without names. Best wishes to all, Dale Dale Braden Department of Chemistry University of Oregon Eugene, OR 97403-1253 genghis@darkwing.uoregon.edu