From s196232@ccs.sogang.ac.kr Wed May 1 04:50:10 1996 Received: from ccs.sogang.ac.kr for s196232@ccs.sogang.ac.kr by www.ccl.net (8.7.1/950822.1) id DAA29676; Wed, 1 May 1996 03:57:15 -0400 (EDT) Received: from localhost by ccs.sogang.ac.kr (8.7.5/Sogang) id QAA15264; Wed, 1 May 1996 16:55:35 +0900 (KST) Date: Wed, 1 May 1996 16:55:35 +0900 (KST) From: Lee Tae Bum X-Sender: s196232@ccs To: chemistry@www.ccl.net Subject: Monte Carlo simulation Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Dear CCLer, I have the book;reviews in Computational Chemistry vol.5. I would like to get some infomation about Monte Carlo simulation. Does anybody recommend the book, homepage, or some people related this field? Truly yours, From topper@cooper.edu Wed May 1 12:50:11 1996 Received: from magnum.cooper.edu for topper@cooper.edu by www.ccl.net (8.7.1/950822.1) id MAA02068; Wed, 1 May 1996 12:32:48 -0400 (EDT) Received: from zeus.cooper.edu by magnum.cooper.edu with SMTP id AA02249 (5.65c/IDA-1.4.4 for ); Wed, 1 May 1996 12:35:00 -0400 Received: by zeus.cooper.edu id AA15495 (5.67b/IDA-1.5 for CHEMISTRY@www.ccl.net); Wed, 1 May 1996 12:31:57 -0400 From: TOPPER ROBERT Message-Id: <199605011631.AA15495@zeus.cooper.edu> Subject: CCL:Monte Carlo simulation (fwd) To: CHEMISTRY@www.ccl.net Date: Wed, 1 May 1996 12:31:56 -0400 (EDT) Cc: topper@cooper.edu (TOPPER ROBERT) X-Mailer: ELM [version 2.4 PL24alpha3] Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit > > Dear CCLer, > > I have the book;reviews in Computational Chemistry vol.5. > I would like to get some infomation about Monte Carlo > simulation. Does anybody recommend the book, homepage, > or some people related this field? The Molecular Monte Carlo Home Page, at http://www.cooper/edu/engineering/chemechem/monte.html has some useful resources, including links to home pages of a number of groups using Monte Carlo methods and to tutorials describing random number generation and Monte Carlo integration. We hope to develop some tutorials specific to molecular simulation in the near future. Best, robert ************************************************************************ Robert Q. Topper email: topper@cooper.edu Asst. Prof. of Chemistry phone: (212) 353-4378 The Cooper Union FAX: (212) 353-4341 51 Astor Place subway: take the 6 to Astor Place New York, NY 10003 USA or the N/R to 8th St/NYU http://www.cooper/edu/engineering/chemechem/depts_info/topper.html ************************************************************************ Check out the Molecular Monte Carlo home page! http://www.cooper/edu/engineering/chemechem/monte.html ************************************************************************ From choic@gusun.acc.georgetown.edu Wed May 1 13:50:11 1996 Received: from gusun.acc.georgetown.edu for choic@gusun.acc.georgetown.edu by www.ccl.net (8.7.1/950822.1) id NAA02378; Wed, 1 May 1996 13:39:52 -0400 (EDT) Received: by gusun.acc.georgetown.edu (SMI-8.6/SMI-SVR4) id NAA28953; Wed, 1 May 1996 13:38:01 -0400 Date: Wed, 1 May 1996 13:38:00 -0400 (EDT) From: Cheol Choi X-Sender: choic@gusun To: chemistry@www.ccl.net Subject: calculation of HFS constants Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Dear collegues, I wish to calculate theoretical hyperfine splitting constants on the basis of ab initio calculation results (spin densities, charge densities, geometries) done for radical species. What program can do this or how can it be done? Thank you! Andrej Krzan Georgetown University Chemistry dept. Washington DC From frederic@ruuci9.chem.ruu.nl Wed May 1 13:54:29 1996 Received: from chemail.chem.ruu.nl for frederic@ruuci9.chem.ruu.nl by www.ccl.net (8.7.1/950822.1) id NAA02345; Wed, 1 May 1996 13:33:08 -0400 (EDT) Received: from RUUCI2 (ruuci2.chem.ruu.nl) by chemail.chem.ruu.nl with SMTP id AA02164 (5.67b/IDA-1.5 for <@chemail.chem.ruu.nl:chemistry@www.ccl.net>); Wed, 1 May 1996 19:33:09 +0200 Received: from RUUCI2 by RUUCI2 via SMTP (940816.SGI.8.6.9/940406.SGI.AUTO) for id TAA07354; Wed, 1 May 1996 19:32:20 +0100 Sender: frederic@ruuci9.chem.ruu.nl Message-Id: <3187AE33.41C6@nmr.chem.ruu.nl> Date: Wed, 01 May 1996 19:32:19 +0100 From: Frederic Bellier Organization: Bijvoet Center NMR Department X-Mailer: Mozilla 2.0 (X11; I; IRIX 5.3 IP22) Mime-Version: 1.0 To: chemistry@www.ccl.net Subject: gauge including atomic orbital References: Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit -- Hello dear CCLer,, In the review Progress in Nuclear Magnetic Resonance Spectroscopy 27 (1995) 325-443 is the article: "Chemical shifts in proteins come of age" from Laszlo Szilagyi. In this article is mentioned, to compute NMR chemical shift, the ab-initio method called GIAO who stand for gauge including atomic orbital (I think). Does someone can tell me what means gauge including atomic orbital in just few lines? I know how works ab-initio calculations so it's just the acronym "gauge including..." which is not clear for me. Thank you for your help. Kind regards. Frederic. ________________________________________________________________________ M. Mr. BELLIER Frederic UTRECHT, University of BIJVOET CENTER FOR BIOMOLECULAR RESEARCH Padualaan 8, 3584 CH Utrecht DEPARTMENT OF NMR SPECTROSCOPY THE NETHERLANDS. http://www-nmr.chem.ruu.nl/ ________________________________________________________________________ FAX : int-(31)-302-537-623 PHONE : int-(31)-302-532-875 EMAIL : frederic@nmr.chem.ruu.nl HOME : http://www-nmr.chem.ruu.nl/users/frederic/frederic.html ________________________________________________________________________ From mstewart@whale.st.usm.edu Wed May 1 13:56:50 1996 Received: from whale.st.usm.edu for mstewart@whale.st.usm.edu by www.ccl.net (8.7.1/950822.1) id NAA02194; Wed, 1 May 1996 13:14:29 -0400 (EDT) Received: from [143.132.85.65] by whale.st.usm.edu (AIX 3.2/UCB 5.64/4.03) id AA29805; Wed, 1 May 1996 12:16:59 -0500 Message-Id: <1.5.4.32.19960501171423.0067e16c@whale.st.usm.edu> X-Sender: mstewart@whale.st.usm.edu X-Mailer: Windows Eudora Light Version 1.5.4 (32) Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Wed, 01 May 1996 12:14:23 -0500 To: chemistry@www.ccl.net From: Mike Stewart Subject: Conference Announcement: 5th Conf. on Current Trends in Computational Chemistry Dear Colleagues: We are pleased to announce the 5th conference on CURRENT TRENDS IN COMPUTATIONAL CHEMISTRY. This symposium, organized by Jackson State University, will cover all areas of Computational Chemistry, as well as Quantum Chemistry. The local host of the conference is US Army Corps of Engineers Waterways Experiments Station in Vicksburg. The meeting will be held at the Holiday Inn of Vicksburg (40 miles west of Jackson), Mississippi, on November 1 & 2, 1996. The format consists of a series of plenary lectures and poster presentations on Friday and Saturday, covering applications as well as theory. In addition, a welcoming reception is scheduled on Friday night and a banquet on Saturday evening. We are planning to publish extended abstracts (up to 4 pages) of all invited talks and poster presentations. Original scientific contributions will be published in a special issue of the Journal of Molecular Structure (THEOCHEM). Manuscripts for inclusion in the special issue should be submitted in triplicate upon arrival at the registration desk. The submitted papers will follow the journal's standard refereeing procedure. Enclosed are Announcement Poster, a registration form, and housing information. The deadline for registration and abstract submission is September 1, 1996. Sincerely, Jerzy Leszczynski Chairman of the Organizing Committee Jackson State University Dept of Chemistry 1400 JR Lynch St. Jackson, MS 39217 Phone: (601) 973-3482 Fax: (601) 973-3674 E-Mail: jerzy2@iris5.jsums.edu PROGRAM The program will include invited papers and contributed posters in all areas of Quantum and Computational Chemistry. INVITED SPEAKERS Charles W. Bauschlicher, Jr. NASA Ames Research Center Pavel Hobza Czech Academy of Sciences Suehiro Iwata Institute of Molecular Science, Okazaki N. Yngve Ohrn University of Florida Josef Paldus University of Waterloo Jean-Louis Rivail Universite Henri Poincare Dennis Salahub Universite de Montreal Harold Scheraga Cornell University Peter Schwerdtfeger University of Auckland Gustavo E. Scuseria Rice University John Stanton University of Texas at Austin Mark Thompson Pacific Northwest Laboratory Updated information on conference activities and the subjects of the invited speakers' talks will be available on the World Wide Web at http://tiger.jsums.edu:8080/~mikes/compconf.htm Registration form: 5th Conference on CURRENT TRENDS IN COMPUTATIONAL CHEMISTRY NOVEMBER 1 & 2, 1996, Jackson, Mississippi 1. NAME: MAILING ADDRESS: TELEPHONE: FAX: E-MAIL: 2. If you wish to present a poster, please indicate the title below. All abstracts are due September 1, 1996 (up to 4 pages in length, presenting author underlined, photo-ready quality, in duplicate) to ensure publication in the Conference Materials. TITLE: AUTHORS: 3. Conference materials, Banquet and reception fee, all meals from breakfast on Friday through dinner on Saturday, coffee and refreshments are included per paid participant. Make checks payable to : Conference on "Current Trends in Computational Chemistry" in accord with the fee structure listed below. Registration fee before September 1, 1996: $150.00 $_______ Registration fee thereafter $200.00 $_______ Registration fee at student discount $ 75.00 $_______ 5. HOUSING: The organizers will not make housing reservations. In order to reserve a room at a special conference rate of $50.00-$60.00 per room, call Holiday Inn of Vicksburg, 3330 Clay Street, Vicksburg, MS 39180. Phone:(601)636-4551, Fax:(601)636-4552. The reservation should be arranged with the Holiday Inn before October 15, 1996. I do___ do not___ plan to stay at the conference hotel. I do___ do not___ plan submit a paper to the special issue of THEOCHEM. _____________________ signature Please type all entries and return to Jerzy Leszczynski, Department of Chemistry, Jackson State University. P.O.Box 17910, Jackson, MS 39217. Mike Stewart, Graduate Polymer Chemist Primary: mstewart@whale.st.usm.edu The University of Southern Mississippi Secondary: mikes@tiger.jsums.edu GS d--@ H-- s+: g+ a- w+@ v+ C++ UA+ N++ 5++ j++ b++@ e+++ u** y+++ n---- From dan@sage.syntex.com Wed May 1 14:50:10 1996 Received: from chub1.syntex.com for dan@sage.syntex.com by www.ccl.net (8.7.1/950822.1) id OAA02781; Wed, 1 May 1996 14:48:19 -0400 (EDT) Received: from sage.syntex.com by SYNTEX.COM (PMDF V4.3-10 #15454) id <01I46V3RQOCG004G3E@SYNTEX.COM>; Wed, 01 May 1996 11:47:46 -0800 (PST) Received: by sage.syntex.com (951211.SGI.8.6.12.PATCH1042/940406.SGI.AUTO) id LAA18849; Wed, 1 May 1996 11:48:06 -0700 Date: Wed, 01 May 1996 11:48:03 -0700 From: dan@sage.syntex.com (Dr. Daniel L. Severance) Subject: Re: CCL:Monte Carlo simulation (fwd) In-reply-to: TOPPER ROBERT "CCL:Monte Carlo simulation (fwd)" (May 1, 12:31pm) To: TOPPER ROBERT Cc: CHEMISTRY@www.ccl.net Message-id: <9605011148.ZM18847@sage.syntex.com> MIME-version: 1.0 X-Mailer: Z-Mail (3.2.2 10apr95 MediaMail) Content-type: text/plain; charset=us-ascii Content-transfer-encoding: 7BIT References: <199605011631.AA15495@zeus.cooper.edu> > The Molecular Monte Carlo Home Page, at > http://www.cooper/edu/engineering/chemechem/monte.html > ^ don't you mean | http://www.cooper.edu/engineering/chemechem/monte.html -- Dr. Daniel L. Severance dan@sage.syntex.com Staff Researcher Work phone:(415) 354-7509 Roche Bioscience (Syntex) Fax (Work):(415) 354-7363 R6W-002, 3401 Hillview Ave Palo Alto, CA 94303 From topper@cooper.edu Wed May 1 15:50:13 1996 Received: from magnum.cooper.edu for topper@cooper.edu by www.ccl.net (8.7.1/950822.1) id PAA02982; Wed, 1 May 1996 15:34:14 -0400 (EDT) Received: from zeus.cooper.edu by magnum.cooper.edu with SMTP id AA22825 (5.65c/IDA-1.4.4 for ); Wed, 1 May 1996 15:28:52 -0400 Received: by zeus.cooper.edu id AA06889 (5.67b/IDA-1.5 for CHEMISTRY@www.ccl.net); Wed, 1 May 1996 15:25:48 -0400 From: TOPPER ROBERT Message-Id: <199605011925.AA06889@zeus.cooper.edu> Subject: CCL:Monte Carlo simulation To: CHEMISTRY@www.ccl.net Date: Wed, 1 May 1996 15:25:47 -0400 (EDT) Cc: topper@cooper.edu (TOPPER ROBERT) X-Mailer: ELM [version 2.4 PL24alpha3] Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit My apologies; I supplied the wrong address for the MMC Home Page. The correct address: http://www.cooper.edu/engineering/chemechem/monte.html Thanks to Dan Severance for the correction. robert ************************************************************************ Robert Q. Topper email: topper@cooper.edu Asst. Prof. of Chemistry phone: (212) 353-4378 The Cooper Union FAX: (212) 353-4341 51 Astor Place subway: take the 6 to Astor Place New York, NY 10003 USA or the N/R to 8th St/NYU http://www.cooper.edu/engineering/chemechem/depts_info/topper.html ************************************************************************ Check out the Molecular Monte Carlo home page! http://www.cooper.edu/engineering/chemechem/monte.html ************************************************************************ From taisung@chem.duke.edu Wed May 1 15:56:19 1996 Received: from chem.duke.edu for taisung@chem.duke.edu by www.ccl.net (8.7.1/950822.1) id OAA02829; Wed, 1 May 1996 14:55:03 -0400 (EDT) Received: from debye.chem.duke.edu (debye.chem.duke.edu [152.3.169.112]) by chem.duke.edu (8.7.4/Duke-1.1) with ESMTP id OAA12467; Wed, 1 May 1996 14:55:03 -0400 (EDT) Received: (taisung@localhost) by debye.chem.duke.edu (8.7.4/Duke-1.1) id OAA01144; Wed, 1 May 1996 14:55:02 -0400 (EDT) Date: Wed, 1 May 1996 14:55:00 -0400 (EDT) From: Taisung Lee X-Sender: taisung@debye To: Frederic Bellier cc: chemistry@www.ccl.net Subject: Re: CCL:gauge including atomic orbital In-Reply-To: <3187AE33.41C6@nmr.chem.ruu.nl> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Hi, I think it's Gauge-Invariant Atomic Orbitals. Following reference maybe useful: J.D.Memory, "Quantum Theory of Magnetic Resonance Parameters" McGraw-Hill Series in Advanced Chemistry. (1968) pp.87 Taisung Lee > Hello dear CCLer,, > > In the review Progress in Nuclear Magnetic Resonance Spectroscopy 27 > (1995) 325-443 is the article: "Chemical shifts in proteins come of age" > from Laszlo Szilagyi. > In this article is mentioned, to compute NMR chemical shift, the > ab-initio method called GIAO who stand for gauge including atomic > orbital (I think). > Does someone can tell me what means gauge including atomic orbital in > just few lines? I know how works ab-initio calculations so it's just the > acronym "gauge including..." which is not clear for me. > > Thank you for your help. > Kind regards. > Frederic. > ________________________________________________________________________ > > M. Mr. BELLIER Frederic > UTRECHT, University of BIJVOET CENTER FOR BIOMOLECULAR RESEARCH > Padualaan 8, 3584 CH Utrecht DEPARTMENT OF NMR SPECTROSCOPY > THE NETHERLANDS. http://www-nmr.chem.ruu.nl/ > ________________________________________________________________________ > > FAX : int-(31)-302-537-623 > PHONE : int-(31)-302-532-875 > EMAIL : frederic@nmr.chem.ruu.nl > HOME : http://www-nmr.chem.ruu.nl/users/frederic/frederic.html > ________________________________________________________________________ > > -------This is added Automatically by the Software-------- > -- Original Sender Envelope Address: frederic@ruuci9.chem.ruu.nl > -- Original Sender From: Address: frederic@ruuci9.chem.ruu.nl > CHEMISTRY@www.ccl.net: Everybody | CHEMISTRY-REQUEST@www.ccl.net: Coordinator > MAILSERV@www.ccl.net: HELP CHEMISTRY or HELP SEARCH | Gopher: www.ccl.net 73 > Anon. ftp: www.ccl.net | CHEMISTRY-SEARCH@www.ccl.net -- archive search > Web: http://www.ccl.net/chemistry.html > > From owner-chemistry@ccl.net Wed May 1 18:50:13 1996 Received: from bedrock.ccl.net for owner-chemistry@ccl.net by www.ccl.net (8.7.1/950822.1) id SAA03785; Wed, 1 May 1996 18:12:57 -0400 (EDT) Received: from scripps.edu for rickr@scripps.edu by bedrock.ccl.net (8.7.1/950822.1) id SAA06956; Wed, 1 May 1996 18:12:40 -0400 (EDT) Received: from aries.scripps.edu by scripps.edu (5.61/1.34) id AA08564; Wed, 1 May 96 15:02:10 -0700 Received: by aries.Scripps.EDU (4.1/SMI-4.1) id AA16164; Wed, 1 May 96 15:01:58 PDT Date: Wed, 1 May 96 15:01:58 PDT From: rickr@scripps.edu (Rick Ross) Message-Id: <9605012201.AA16164@aries.Scripps.EDU> To: chemistry@ccl.net, neomig@polymer.uakron.edu Subject: Pitt_Mod_Group_Meeting Pittsburgh Molecular Modeling Group Spring 1996 Meeting May 24, 1996 Room 135, Department of Chemistry Chevron Science Center University of Pittsburgh Pittsburgh, PA All Interested Folks Welcome for All or Part Agenda: 9:15-9:45 Informal Discussion 9:45-9:50 Welcome - Dr. Richard B. Ross - PPG Industries, Inc. 9:50-10:25 Prof. Kenneth Jordan (U. of Pitt.) Ab Initio and Force Field Simulations of Water Clusters (with M. Pedulla) 10:25-11:00 Prof. Janet Del Bene (Youngstown St. U.) Tracking Down the Elusive Proton in Hydrogen Bonded Complexes 11:00-11:35 Prof. David Ewing (John Carrol U.) Quantum Chemical Modeling of the Interaction of Perfluorethers with Aluminum Surfaces (with S. Slaby) 11:35-12:45 Lunch Break 12:45-1:20 Prof. Craig Wilcox (U. of Pitt.) Experiments on Polar Group Effects in Binding and Reactivity 1:20-1:55 Mr. Brian Lynton (U. of Pitt.) Synthetic Approaches to the Design of Artificial Receptors 1:55-2:40 Dr. Michael Doyle (Molecular Simulations, Inc.) Molecular Modeling - An Historical Perspective and Future Directions 2:40-3:00 Break 3:00-3:50 Dr. George Famini (U.S. Army Edgewood Research, Development and Engineering Center) Using Molecular Orbital Based Parameters to Predict Properties 3:50-4:30 Dr. Michael Doyle (Molecular Simulations, Inc.) Structure Activity and Atomistic Modeling of Corrosion Inhibitors 4:30-6:00 Informal Discussion/Molecular Modeling Demonstrations Hosted by Professor Kenneth Jordan (U. of Pittsburgh) and Dr. Richard B. Ross (PPG Industries, Inc.) To reserve a seat in advance or for more information send email to Dr. Richard B. Ross at rickr@ppg.scripps.edu or call 412-492-5359. From jerry@dft.chem.cuhk.hk Wed May 1 21:50:15 1996 Received: from iris.chem.cuhk.hk for jerry@dft.chem.cuhk.hk by www.ccl.net (8.7.1/950822.1) id VAA04642; Wed, 1 May 1996 21:01:15 -0400 (EDT) Received: from dft.chem.cuhk.hk by iris.chem.cuhk.hk via SMTP (931110.SGI/940406.SGI.AUTO) for chemistry@www.ccl.net id AA18897; Thu, 2 May 96 09:00:33 +0800 Received: by dft (950511.SGI.8.6.12.PATCH526/930416.SGI.AUTO) id JAA09614; Thu, 2 May 1996 09:00:31 +0800 Date: Thu, 2 May 1996 09:00:30 +0800 (HKT) From: Jerry C C Chan To: chemistry@www.ccl.net Subject: Summary: NBO for transition metal Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Dear Netters, Some days ago I posted a message below: > I notice that NBO has already been applied to transition metal > containing systems. Could anybody give me some references which concern > the transition metal-ligand interaction using NBO analysis, in addition to > the work by Maseras and Morokuma CPL 1992. > I have tried applying NBO analysis to [Co(NH3)5Cl]2+ and I find > some difficulties in interpretating some of the results: > if LP ( 1) N 3 / BD*( 1)Co 1-Cl 2, "lone pair electrons of N (donor) / > antibonding orbital of Co-Cl (acceptor)", is interpreted as an > indication of the importance of the resonance N-Co <-> N(+)-Co Cl(-), how > should one interprete BD ( 1)Co 1-Cl 2 / RY*(16)Co 1 ? I would like to express my gratitude to all who response to my query. Special thanks are due to Profs. Frank Weinhold, Jay Badenhoop, Martin Kaupp and Eric Glendening. I wish my summary would contribute to the popularity of NBO analysis. ************* > 1. Is it justified if NBO scheme is used to analyze the SCF density > obtained by dft method? While not developed for DFT wavefunctions, NBO analyzes the 1st order density matrix, and therefore should be more compatible with density- based methods than methods which analyze the wavefunction to determine bond order. We have had much success (and yes, some surprising results which were found later to be consistent with experimental results) from NBO analysis of coordination complexes. > 2. Is there any physical meaning associated with the energy of the > natural bonding orbital? I don't understand the physical picture of > "Population inversion found on atom ..." although there is an > operational explanation in the NBO manual. The natural bond orbitals are calculated as the 1- and 2-center set of orthogonal orbitals which takes account of the greatest amount of the electron density in a maximum-occupancy sense. Each orbital has an energy or eigenvalue associated with it, just as the atomic orbitals and molecular orbitals do. However, sometimes one or more orbitals will be higher in occupancy, but also higher in energy than one or more other orbitals. Therefore the ordering from highest to lowest occupancy and the ordering from lowest to highest energy will not be the same. Often this occurs if you have a large number of orbitals which are fairly close in energy and population, which is common in these coordination complexes. This warning message about "population inversion" just alerts you to this different ordering of the orbitals, and does not indicate the orbitals are of inferior quality or are mislabeled in any way. > 3. How can the NBO result be considered as valid? NHO procedure > fail in CO2 (JACS, 1980) because of the miscount of the total number > of orbitals. However, if the total number of orbitals is counted > correctly but some of the BD and *BD occupancy are < 1.7 and > 0.4, > respectively, can we still accept the NBO result? First, the NBO procedure has been modified to handle a wider variety of cases than in 1980. I do not believe that the CO2 case fails with the latest version of NBO. ... However, you must not just consider the NBO's listed in the table. This is the "best" localized set of orbitals, but low-occupancy bonding orbitals (BD or LP) or high-occupancy anti-bonds (BD*) indicates a highly delocalized molecule. You must also consider the list of second order perturbative estimates of the donor-acceptor interactions. This list indicates the most important delocalizations from bonding to antibonding orbitals. You will find both Co --> ligand and backbonding ligand --> Co interactions. ... In addition, our group has developed a quantitative NBO-based resonance theory, which calculates a set of localized resonance structures and associated resonance weights which best describe the full density, then calculates not only a bond order but also partitions the bond into covalent and ionic contributions to this bond order based on the bond polarization coefficients. This bond order is more comparable to Bader's bond order than a measure of bond order only based on the "best" localized NBO structure (resonance structure of highest "weight") only. Unfortunately, the method has been developed for organic molecules, and cannot handle transition metal complexes without further development. Jay Badenhoop Department of Chemistry Southern Illinois University at Carbondale ******************* > In the Second Order Perturbative Analysis of Co(NH3)5H2O, I get > BD*( 1)Co 1- N 4 /299. BD*( 1)Co 1- N 5 2168.13 0.01 0.249 > I really do not understand the physical picture implied by these large > interactions. The BD*-BD* 2nd-order energies should be ignored, since the BD* is not even approximately "doubly occupied" and the PT picture is no longer valid. (NBO prints out these entries for convenience in analyzing excited states, which may have significant population in BD* orbitals.) Only the donor(LP,BD)-acceptor(BD*,RY*) entries have physical significance in this case. FW ******************* > I notice that NBO has already been applied to transition metal > containing systems. Could anybody give me some references which concern > the transition metal-ligand interaction using NBO analysis, in addition > to the work by Maseras and Morokuma CPL 1992. > We frequently use the NPA, and to a lesser extent the NBO analysis for TM compounds. Some references are: Inorg. Chem. 1994,33,2122; Chem.Eur.J. 1996,2,348; J.Am.Chem.Soc. 1996,118,3018. > I have tried applying NBO analysis to [Co(NH3)5Cl]2+ and I find > some difficulties in interpretating some of the results: > One principle problem with the NBO part is that for many TM compounds the program fails to find _one_ Lewis structure. Thus, you should be very careful in examining the Lewis structure you get. Does it make any chemical sense? How large are, e.g., the energy terms in the second-order perturbation theory analysis (values larger than, say, 30-50 kcal/Mol clearly tell you that your Lewis structure does not describe the density matrix well) ? Of course there are other criteria one may look at, such as the percentage of the density matrix described by the Lewis structure. To get around these problems, Weinhold and coworkers have meanwhile developed an extension they call 'natural resonance theory' which expands the density matrix in several NBO Lewis structures. While the theory is, as far as I know, at the moment just available as an internal report of the University of Wisconsin, some interesting applications (to main group species) may be found in: J. Chem. Educ. 1995, 72, 583. I expect this to give a much improved analysis for TM systems as well and hope it will be available soon (it's now part of the NBO 4.0 program). Of course the NPA is no problem, so charges and NAO populations may be used safely even with the present version. One point regards the use of NBO/NPA with DFT (Kohn-Sham) calculations: In principle the Kohn-Sham orbitals only describe a wavefunction for the so-called 'noninteracting reference system' and thus can not be interpreted as the wavefunction for the real system. In practice, however, this does not create any problems. Comparisons with HF, MP2, etc.... density matrices show that the KS orbitals give the expected characteristics (e.g. showing effects of electron correlation) and we have found them to provide a useful basis for qualitative interpretations, in particular for TM systems. Hope this helps a bit. Regards, Martin Kaupp ------------------------------------------------------------------ | Dr. Martin Kaupp | | Max-Planck-Institut fuer Festkoerperforschung, | | Heisenbergstrasse 1, D-70569 Stuttgart, Germany, | | Tel.: country-code+711/689-1532 | | Fax.: country-code+711/689-1562 | | email: kaupp@vsibm1.mpi-stuttgart.mpg.de | | | | and Institut fuer Theoretische Chemie, Universitaet Stuttgart, | | Pfaffenwaldring 55, D-70569 Stuttgart, Germany | | Tel.: country-code+711/685-4399 | | Fax.: country-code+711/685-4442 | | http://www.theochem.uni-stuttgart.de/~kaupp/ | ------------------------------------------------------------------ ************************ The Co-Cl bond that NBO calculates is probably highly polarized toward Cl and might alternatively be described as a Cl lone pair with fairly strong charge transfer interaction with Co. The interaction is apparently strong enough that NBO calculates a bond between these two atoms. Co-Cl --> RY*(16) is then a separate charge transfer interaction between the Cl lone pair and a different hybrid on Co (presumably one of the 3d orbitals?). I gather that you're using the NBO perturbative analysis to judge the degree of delocalization between the ligands and Co. If so, you should probably force NBO to treat the ligands consistently. That is, if NBO doesn't calculate any bonds between Co and NH3, then prevent the program for calculating a Co-Cl bond. This is accomplished with NBO $CHOOSE keylist, which is described in the NBO manual. $CHOOSE allows the user to stipulate the pattern of bonds (the Lewis structure) that NBO will calculate. For your complex, only ask for NH bonds; no bonds would then be calculated between Co and N or Cl. If you don't have an NBO manual and would like to try $CHOOSE, send me a copy of your input deck. I'll add the $CHOOSE keylist to it (it's fairly simple) and return the file to you. Eric Glendening Department of Chemistry Indiana State University Terre Haute, IN 47809 ericg@chem.indstate.edu ************************** The rule of thumb that I use is to neglect any interaction that is an order of magnitude weaker than the strongest appearing in NBO's perturbative analysis. This works well whenever one is looking for a qualitative description of the delocalization patterns in a molecule (or complex, as in your case). So I'd ignore the RY* interaction. ... It is certainly reasonable to judge the degree of covalent character from the presence or absence of a bonding NBO. If NBO calculates a bond, then the polarization coefficients give a quantitative measure of covalent character; if NBO calculates a lone pair, then covalency can be judged from the strength of the orbital interactions. You won't however be able to compare the covalency of two interactions when NBO assigns one a bond and the other a lone pair. While it is likely that the interaction with the bonding NBO should have higher covalent character, this may not always be the case. I really recommend $CHOOSE as it will allow a consistent comparison of all interactions based on lone pair delocalizations. Eric Glendening ************************ [Co(NH3)5Cl]2+ CO 0.00000 0.00000 0.00000 CL -1.72778 -0.00000 -1.47168 N 1.47849 0.00000 1.27277 N 1.25572 -0.00000 -1.50461 N -0.03050 -1.96150 -0.01613 N -0.03050 1.96150 -0.01613 N -1.27561 0.00000 1.51536 H 1.15559 0.00000 2.23183 H 2.07308 0.81190 1.16605 ... Here's the CHOOSE input for your Co complex: $nbo $end $choose lone 1 3 2 4 3 1 4 1 5 1 6 1 7 1 end bond s 3 8 s 3 9 s 3 10 s 4 11 s 4 12 s 4 13 s 5 14 s 5 15 s 5 16 s 6 17 s 6 18 s 6 19 s 7 20 s 7 21 s 7 22 end $end Note that the "resonance" keyword is not needed when the Lewis structure is specified in $choose. $choose is free-format and reads as follows: First the lone pairs (lone ... end); atom 1 (Co) has 3, atom 2 (Cl) has 4, etc. Then the bonds (bond ... end); a single bond between atoms 3 and 8, a single bond between atoms 3 and 9, etc. Attach the $choose...$end input to the end of your input deck and run; no need to modify your input deck in any other way. NBO always searches the input deck for $choose and uses it if available. Otherwise, NBO defaults to its standard search for a Lewis structure. Also, $choose input will in no way affect the population analysis. Just run NBO once; you'll get the atomic charges and $choose Lewis structure in one calculation. Eric ************************* From WEINHOLD@chem.wisc.eduThu May 2 08:35:05 1996 Date: Mon, 29 Apr 96 11:44 CST From: WEINHOLD@chem.wisc.edu To: jerry@dft Subject: Re: NBO LICENSE AGREEMENT: NATURAL BOND ORBITAL 4.0 PROGRAM Name ______________________________ Institution ______________________________ Address ______________________________ ______________________________ E-mail ______________________________ Telephone ______________________________ I agree that the NBO 4.0 program will remain under my direct control and that the program will not be redistributed to others in any form. ______________________________ ________ signature date Please return this form with $100 remittance (payable to Theoretical Chemistry Institute) to: Theoretical Chemistry Institute c/o Sherry Naffz Department of Chemistry University of Wisconsin Madison, WI 53705 _____ additional manuals @ $30/each (includes shipping and handling)