From ߴz@apmsun.mpei.ac.ru Sun Apr 13 10:35:56 1997 Received: from apmsun.mpei.ac.ru for ߴz@apmsun.mpei.ac.ru by www.ccl.net (8.8.3/950822.1) id JAA13401; Sun, 13 Apr 1997 09:41:35 -0400 (EDT) Received: from srv-m.mpei.ac.ru by apmsun.mpei.ac.ru (SMI-8.6/SMI-SVR4) id RAA23905; Sun, 13 Apr 1997 17:29:40 -0400 Received: by srv-m.mpei.ac.ru (5.x/SMI-SVR4) id AA14961; Sun, 13 Apr 1997 17:27:26 -0300 From: (Chemical Physics Institute) Message-Id: <9704132027.AA14961@srv-m.mpei.ac.ru> Subject: MMX and all that To: chemistry@www.ccl.net (Computational Chemistry List) Date: Sun, 13 Apr 1997 17:27:25 -0300 (GMT) X-Mailer: ELM [version 2.4 PL23] Content-Type: text Dear CCLers, lovers of molecular simulation and supramolecular chemistry! Some days ago, I posted a question concerning the MMX force field. Here, I am presenting a summary of answers to my question. The original question was as follows: Dear Colleagues, users of PCModel, I am very interested in how the MMX field treat metal cations. Any hints or references would be greatly appreciated. Other experience in using this force field would also be rather precious. All answers will be summarized. With best wishes for successful calculations Alexander Bagatur'yants ******************************************************************** * Prof. Alexander A. Bagatur'yants Phone: (007)-(095)-9362588 * * Center on Photochemistry Fax: (007)-(095)-9361255 * * Russian Academy of Science (007)-(095)-4335325 * * ul. Novatorov 7a, Moscow E-mail phch@srv-m.mpei.ac.ru * * 117421 RUSSIA sasha@mx.icp.rssi.ru * ******************************************************************** I received the following answers: From: "Yurii Kruglyak" Subject: CCL:MMX for systems with metal ions Dear Alexander, Dr. Victor Kuzmin, Dept of Molecular Electronics, Odessa State University victor@ignet.odessa.ua and his group have developed DISMOL, MMX like soft specially designed for molecular systems with metal ions. Some initial references to this soft may be found in Tim Clark, A handbook of computational chemistry, "Mir", Moscow, 1990, p. 376. Sincerely, -- ======================================================================= Professor Yuri Kruglyak Department of Molecular Electronics kruglyak@qnet.odessa.ua Odessa State University quantum@ignet.odessa.ua Dvoryanskaya St. 2 FaxLine: +380-482-637785 ODESSA 270100 UKRAINE Voice : +380-482-603314 ======================================================================= QuantumNet Public Association: http://www.patriot.net/users/eslone/qnet [QuantumNet U.S. Office] http://194.44.93.1/friends/qnet M http://mos.net/hp/nexus I http://www.cs.wayne.edu/~kjz/ismebc/ResGrps.html R http://freenet.kiev.ua/ciesin/partners.html R Gopher://www.ccl.net:73/1m/info/societies/Quantum-Net O R S ======================================================================= Richard P. Feynman' Foundation Friends of Tuva' FSU Office: www.patriot.net/users/eslone/tuva.htm ======================================================================= From: schlecmf@esvax.dnet.dupont.com Subject: CCL:MMX organometallic implementation Prof. Bagatur'yants: The MMX algorithm for modeling organometallic compounds is described briefly in the documentation to the PCMODEL program, if you have that available, and also in a book chapter which the MMX developers have published: Gajewski, J. J.; Gilbert, K. E.; McKelvey, J. in Advances in Molecular Modeling, Vol. 2, (ed. Liotta, D.), JAI Press, Greenwich, CT (1990), pp 65-92. There is also a very good recent book on the general subject of organometallic force field modeling: Comba, P.; Hambley, T. W. Molecular Modeling of Inorganic Compounds. VCH, New York (1995). Basically, except for a few main group metals such as silicon and aluminum (which have their own parameter sets), MMX has a "generic" metal atom type which can be modified for specific metallic elements by such parameters as charge and covalent radius. Metal-organic interactions can be modeled as "covalent" bonds, in which case a set of force field parameters (bond stretch, angle bend, torsions, etc.) are used, or as "coordination" bonds, in which case MMX uses an electrostatic-based potential which operates upon the metal center and the lone electron pairs of the ligand donor atom(s). There are provisions for invoking the trans effect, and high spin/low spin in different coordination geometries. I hope that this has been of some help to you. My interest in the area comes from the fact that, hopefully, I will soon finish a manuscript for an entry-level book for VCH on force field modeling which uses MMX examples. Regards... ------------------------------ Matthew F. Schlecht DuPont Agricultural Products Newark, DE 19714-0030 USA schlecmf@esvax.dnet.dupont.com ------------------------------ From: Alexandre Hocquet Subject: Re: CCL:MMX Priviet Sasha, The actual description of the MMX forcefield is in a book which i never could obtain : Gajewski, Gilbert, McKelvey, Advances in Molecular Modelling, Liotta Ed, JAI Press, Greenwich, CT, 1990. If, by chance, you encounter it, i am greatly interested in a copy. However, some information about how this forcefield treats inorganics and organometallics can be found in : Mackie, Baird, Organometallics, 1992, 11, 3712-3724 Hope this helps... Alexandre Hocquet Laboratorio de Cristalografia Facultad de Ciencias Fisicas Universidad de Chile Blanco Encalada, 2008 Santiago Centro Chile fono : 56 2 678 45 19 fax : 56 2 696 73 59 email : ahocquet@cec.uchile.cl From: Lars Hemmingsen Hi Alexander ! Concerning your question about MMX and metal ions. The review by Benjamin P. Hay (in Coordination Chemistry Reviews, 1993, 126, 177-236) is a good place to start - among other things it contains a listing of published molecular mechanical calculations on coordination compounds, where also some MM2 calculations are referenced. good luck, yours Lars Hemmingsen I am very grateful to all who responded to my question! Being a rather poor lover of these topics, I kindly ask all who knows to point to a freeware with MMX implemented. Best Luck to everybody! Yours Alexander A. Bagatur'yants ******************************************************************** * Prof. Alexander A. Bagatur'yants Phone: (007)-(095)-9362588 * * Center on Photochemistry Fax: (007)-(095)-9361255 * * Russian Academy of Science (007)-(095)-4335325 * * ul. Novatorov 7a, Moscow E-mail phch@srv-m.mpei.ac.ru * * 117421 RUSSIA sasha@mx.icp.rssi.ru * ******************************************************************** From buyong@ibmnla.chem.uga.edu Sun Apr 13 21:36:02 1997 Received: from dns1.uga.edu for buyong@ibmnla.chem.uga.edu by www.ccl.net (8.8.3/950822.1) id VAA15976; Sun, 13 Apr 1997 21:08:52 -0400 (EDT) From: Received: from ibmnla.chem.uga.edu (ibmnla.chem.uga.edu [128.192.5.8]) by dns1.uga.edu (8.8.5/8.8.3) with SMTP id VAA20108; Sun, 13 Apr 1997 21:08:53 -0400 Received: from localhost by ibmnla.chem.uga.edu (AIX 3.2/UCB 5.64/4.03) id AA10209; Sun, 13 Apr 1997 21:08:16 -0400 Date: Sun, 13 Apr 1997 21:08:14 -0400 (EDT) To: michael nolan Cc: chemistry@www.ccl.net Subject: Re: CCL:G:symmetry. In-Reply-To: Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Dear Michael: Your problem comes from that most quantum mechanical package can not deal with degenerated orbitals. Therefore,the highest undegenrated subgroup (C2v in your case, for example) is used in calculation. You may force your molecule in right symmetry by constructing z-matrix or cartesian coordinates with constrain symetry related variables. For example, constraning all bond lengths and angles the same for your molecule. Thus, even though (G94) indicates that working group is C2v, you still get what you want. If you want the information about MOs, you have to transform the MO symmetry in subgroup presentation back to actual symmetry, sometimes. Good luck ================================================================= Dr. Buyong Ma buyong@ibmnla.chem.uga.edu Computational Center for Molecular Structure and Design Department of Chemistry University of Georgia Athens, Georgia 30602 USA Voice (706) 542-2044 ================================================================= On Sat, 12 Apr 1997, michael nolan wrote: > > Dia dhit CCL. > > I'm carrying out a geometry optimisation of the cyclopentadienyl anion, > but there seems to be a slight problem. Using what little infomration I > could find on the geomtry of this molecules (Dewar et al JACS 1973) I get > either C2v or Cs symmetry. What I want is D5h symmetry, as this provides > the correct designation of the MOs to be used in interacting with a > transition metal carbonyl. > Is there any way, using GAMESS-UK or Gaussian94 to somehow force D5h > symmetry on this molecule or does anyone know of any previous claculations > on the geometry of Cp-. > > Any answers are gratefully recieved. > > yours > michael > > > > Der Kobold hat gesprochen > ****************************************************************************** > Michael Nolan (nearly BSc.) Dublin City University (quantum chem.) > 41 Woodview Chemistry + German Year 4 > Lucan > Co. Dublin > Ireland / Republic of Ireland / ROI / Eire > > Email: Maiden@redbrick.dcu.ie > ****************************************************************************** > > > > > > > > > -------This is added Automatically by the Software-------- > -- Original Sender Envelope Address: maiden@RedBrick.DCU.IE > -- Original Sender From: Address: maiden@RedBrick.DCU.IE > 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 > >