From r.ragno@mail.caspur.it Fri Jul 25 03:22:07 1997 Received: from mail.caspur.it for r.ragno@mail.caspur.it by www.ccl.net (8.8.3/950822.1) id CAA00947; Fri, 25 Jul 1997 02:31:56 -0400 (EDT) Received: from naxos.caspur.it (naxos.caspur.it [193.204.5.8]) by mail.caspur.it (8.8.6/8.8.6) with ESMTP id IAA24256 for ; Fri, 25 Jul 1997 08:31:48 +0200 Received: from localhost (ragno@localhost) by naxos.caspur.it (8.8.6/8.8.6) with SMTP id IAA08984 for ; Fri, 25 Jul 1997 08:31:43 +0200 (MET DST) Date: Fri, 25 Jul 1997 08:31:43 +0200 (MET DST) From: Antonello Mai and Gianluca Sbardella To: chemistry@www.ccl.net Subject: chemistry@www.ccl.net (fwd) Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII *************************************************************** * * * Dr. Antonello Mai, Ph.D. Dr. Gianluca Sbardella, Ph.D. * * "The Wizard of Oz" "Merlino" * * * * Dip. Studi Farmaceutici E-mail: r.ragno@caspur.it * * Universita' "La Sapienza" Phone: 39-6-49913814 * * P.le A. Moro, 5 Fax: 39-6-491491 * * 00185 Roma * * ITALY * * * * "Il destino e' quel che e', non c'e' scampo piu' per me.." * * (Gene Wilder, "Frankenstein Junior") * * * * "Destiny, destiny, no escaping that for me..." * * (Gene Wilder, "Young Frankenstein") * * * *************************************************************** ---------- Forwarded message ---------- Date: Thu, 24 Jul 1997 00:38:42 +0200 From: Shu-Kun Lin To: r.ragno@caspur.it Subject: chemistry@www.ccl.net Dear colleague, Can you please tell me how can I subscribe to chemistry@www.ccl.net? Please do me a favour by forwarding the following message to it: Dear colleagues: The First Electronic Conference on Synthetic Organic Chemistry (ECSOC-1) will be held on the Internet and Web during September 1- 30, 1997. The conference website is http://mdpi.org/ecsoc-1.htm in the US and http://www.unibas.ch/mdpi/ecsoc-1.htm in Europe To register as a participant, send by e-mail a one-line message: Subscribe ecsoc Your-first-name Your-last-name to: listserv@listserv.arizona.edu Part of the papers are listed at http://mdpi.org/ecsoc/posters/postersn.htm or http://www.unibas.ch/mdpi/ecsoc/posters/postersn.htm The deadline for sending abstracts for consideration is extended to 30 July 1997. The Deadline for sending posters will be 15 August 1997. Sincerely, Shu-Kun Lin ecsoc-1@mdpi.org From c72463@s06subz2.uibk.ac.at Fri Jul 25 11:13:29 1997 Received: from ms1.uibk.ac.at for c72463@s06subz2.uibk.ac.at by www.ccl.net (8.8.3/950822.1) id KAA03140; Fri, 25 Jul 1997 10:33:48 -0400 (EDT) Received: from s06subz2.uibk.ac.at (s06subz2.uibk.ac.at [138.232.10.13]) by ms1.uibk.ac.at (8.8.5a) with ESMTP id QAA14343; Fri, 25 Jul 1997 16:33:47 +0200 (CEST); from c72463@s06subz2.uibk.ac.at for Received: from S06SUBZ2/SpoolDir by s06subz2.uibk.ac.at (Mercury 1.31); 25 Jul 97 16:34:00 +0100 Received: from SpoolDir by S06SUBZ2 (Mercury 1.31); 25 Jul 97 16:33:46 +0100 From: "GERHARD BISCHOF" Organization: University of Innsbruck, Austria To: chemistry@www.ccl.net Date: Fri, 25 Jul 1997 16:33:38 +0100 Subject: tungsten parameters for semi-empirical calculations X-Confirm-Reading-To: "GERHARD BISCHOF" X-pmrqc: 1 Priority: normal X-mailer: Pegasus Mail for Windows (v2.54) Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=unknown-8bit Content-Transfer-Encoding: 8bit Hallo, I would be grateful to receive any information concerning parameter set for the tungsten atoms available for INDO ( ZINDO/1) quantum chemical calculations. Thank you in advance ! Dr. Renat Nazmutdinov (University of Innsbruck) ************************************************************************** Gerhard Bischof E-mail:Gerhard.Bischof@uibk.ac.at Tel:<0043>512-507-5154 Fax:<0043>512-507-2934 Universit„t Innsbruck Inst. f. Allg., Anorg. und Theor. Chemie Innrain 52 A-6020 Innsbruck Austria *************************************************************************** From support@mathtrek.com Fri Jul 25 12:30:17 1997 Received: from granite.sentex.net for support@mathtrek.com by www.ccl.net (8.8.3/950822.1) id LAA03461; Fri, 25 Jul 1997 11:33:33 -0400 (EDT) Received: from p12a.silicon.sentex.ca (p12a.silicon.sentex.ca [207.245.212.45]) by granite.sentex.net (8.8.6/8.6.9) with SMTP id LAA19664; Fri, 25 Jul 1997 11:42:40 -0400 (EDT) Message-Id: <3.0.16.19970725113112.2dcfd082@mathtrek.com> X-Sender: mathtrek@mathtrek.com (Unverified) X-Mailer: Windows Eudora Pro Version 3.0 (16) Date: Fri, 25 Jul 1997 11:31:17 -0400 To: "Paul G. Tratnyek" , chemistry@www.ccl.net From: "W. R. Smith" Subject: Re: CCL:mac program for solving chemical equilibria Cc: i1s@psu.edu (Inge Schuster) Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Hello, At last, a "computational chemistry" issue that has nothing too do with QM! >At 09:14 PM 7/24/97 -0800, Paul G. Tratnyek wrote: >>Hi! Does anyone know of any program for the Mac which can do calculations >>associated with simultaneous chemical equilibria, titrations, etc. in >>non-aqueous media ( where pH is not a factor)? > [The most sophisticated speciation programs] >I have seen are for >geochemistry. They can handle lots of species, speciation at solid >surfaces, etc. > >Of course, the concern of geochemists is exclusively with aqueous systems. > >The most recent one I have seen running on a Mac is ChemEQL 2.0. Info at: > > http://www.eawag.ch/soft/chemeql.html I must respond to the comment in [brackets] concerning "sophistication". IMHO, most existing "speciation programs", the one mentioned being an example (the name itself even implies that such calculations are special to the domain of geochemistry) are based on 30-year-old thermodynamic and numerical analysis technology. Lots has happened since then! There abound DOS-based geochemistry programs for aqueous systems dating from the 60's and early 70's. They generally contain tightly integrated computational algorithms and aqueous-system databases (the latter of which one must usually accept as realistic thermodynamic descriptions of the system). The program mentioned by Tratnyek, although it runs on a Mac (using a little better hardware technology than DOS :-)), appears to one of the more advanced in its class, in that it can accept user thermodynamic data. However, it is still very specific to aqueous systems - and it is likely based on the old numerical analysis technology (but one can't tell from its description). Most geochemists continue to believe that the computational technology originally developed in the 60's and early 70's for aqueous systems (equilibrium constant equations + Newton-Raphson numerical analysis technology) is the best (and only) appropriate approach for such problems. In reality, aquatic speciation problems are only a special case of general reaction equilibrium problems. Apart from appropriate thermodyamic models, the non-domain-specific technology, in terms of the computational kernel that is central to such calculations, has advanced considerably. This fact is not generally realized in the geochemical community. For example, on page 517 of "Thermodynamics in Geochemistry", G. M. Anderson and D. A. Crerar, Oxford university Press, 1993, there is the following sentences: "There is an important fundamental distinction between the free energy based programs and those using equilibrium constants, and this often determines which method to use in specific applications. The free energy programs actually require much more fundamental thermodynamic information, and this can restrict their usefulness" And on p. 400 of "Geochemical Thermodynamics", 2nd edition, D. K. Nordstrom and J. l. Munoz, Blackwell, 1994: "The only difference worth underscoring here is that a program that accepts only free energy values for the operating database makes it far more difficult to obtain reliable values for aqueous species than it is with a program that uses equilibrium constants. Some free energy values of aqueous species do not exist because the measurements have not been made, whereas the equilibrium constants typically are available:. Both the above statements are widely believed in the geochemistry community - and both are DEAD WRONG. The technology to utilize either type of data (species-specifc free energies or reaction sets with their associated equilibroum constants) has been available since 1982 (section 9.4 of "Chemical reaction Equilibrium Analysis: Theory and Algorithms", W. R. Smith and R. W. Missen, Wiley-Interscience, 1982; Krieger, 1991). An algorithm based on simple linear algebra can be used to convert back and forth between species and reaction data, (This algorithm is incorporated within Mathtrek System's EQS4WIN software - URL below). Comments/discussion on these points are most welcome - any geochemists lurking on the list? How about physical chemists - does anyone like the NASA chemical equilibrium algorithms? -- W. R. Smith, PhD, P. Eng., Senior Scientist, Mathtrek Systems -- 3-304 Stone Road West, Suite 165, Guelph, Ontario CANADA N1G 4W4 EMail: support@mathtrek.com Tel:519-763-1356,FAX:519-763-4525 --------------------- http://www.mathtrek.com --------------------- -Mathtrek Systems - Home of EQS4WIN Chemical Equilibrium Software - From ccl@www.ccl.net Fri Jul 25 15:13:33 1997 Received: from bedrock.ccl.net for ccl@www.ccl.net by www.ccl.net (8.8.3/950822.1) id PAA04972; Fri, 25 Jul 1997 15:10:42 -0400 (EDT) Received: from destille.chemie.de for claessen@chemie.de by bedrock.ccl.net (8.8.6/950822.1) id PAA08113; Fri, 25 Jul 1997 15:10:39 -0400 (EDT) Received: by destille.chemie.de (Smail3.2.0.90) from claessen (132.187.248.145) with smtp id ; Fri, 25 Jul 1997 21:10:21 +0200 (MET DST) Message-Id: Comments: Authenticated sender is From: "Rolf Claessen" Organization: University of Wuerzburg, Dept. of Chemistry To: chemconf@umdd.umd.edu, CHEMED-L@UWF.EDU, chemistry@ccl.net, CICOURSE@IUBVM.INDIANA.EDU, orgchem@extreme.chem.rpi.edu, pharm@dmu.ac.uk, ysn@crow-t-robot.stanford.edu Date: Fri, 25 Jul 1997 21:08:04 +0000 MIME-Version: 1.0 Content-type: text/plain; charset=US-ASCII Content-transfer-encoding: 7BIT Subject: Top 5% Chemistry Sites Reply-to: claessen@chemie.de Priority: normal X-mailer: Pegasus Mail for Win32 (v2.52) Top 5% Chemistry Sites Apply for this award, if you maintain a chemistry related site. It should be easy to navigate, highly informative and well designed. http://www.geocities.com/Tokyo/5243/home_en.htm You can aslo review the winners of the last months at the address. Yours Rolf Claessen __________________________ claessen@chemie.de http://www.geocities.com/Tokyo/5243/home_en.htm ____________ Rolf Claessen's Chemistry Index http://www.chemie.de/~claessen claessen@chemie.de From dew01@xray5.chem.louisville.edu Fri Jul 25 16:13:34 1997 Received: from xray5.chem.louisville.edu for dew01@xray5.chem.louisville.edu by www.ccl.net (8.8.3/950822.1) id PAA05319; Fri, 25 Jul 1997 15:41:43 -0400 (EDT) Received: (from dew01@localhost) by xray5.chem.louisville.edu (950413.SGI.8.6.12/950213.SGI.AUTOCF) id PAA04445 for CHEMISTRY@www.ccl.net; Fri, 25 Jul 1997 15:45:09 -0400 From: "Donald E. Williams" Message-Id: <9707251545.ZM4443@xray5.chem.louisville.edu> Date: Fri, 25 Jul 1997 15:45:09 -0400 X-Mailer: Z-Mail (3.2.3 08feb96 MediaMail) To: CHEMISTRY@www.ccl.net Subject: Nature of the hydrogen bond Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii > > >Merethe.Sjovoll@hre.hydro.com writes: >I am interesting in sharing any experience people have with mimicing hydrogen >bonds in forcefields. The main contribution to an O...H bond is obviously the >coulombic interaction. The other thing is dispersion. >The coulombic interaction is usually represented by two point charges and >dispersion by a -C/R**6 term in a forcefield - I have also seen the term >R/R**10 >used. > However, the hydrogen bonds also have a directional character which is not >described by this simple model. >Are really forcefields of the form described above generally able to describe >structures with hydrogen bonds? >I would very much like to know the view of my colleagues on what a hydrogen >bond really is made of and what it takes to describe it. >Best wishes >Merethe Perhaps the most commonly used force field model for the hydrogen bond, especially O-H...O, is the "disappearing hydrogen" model. This intermolecular force field is based on (12-6-1) functional form, representing repulsion, dispersion, and coulombic interaction. This model is non-directional, and assigns *zero* dispersion and *zero* repulsion. Now many say that the main component of h-bond energy is electrostatic. However, in the disappearing hydrogen model, by far the main component is the reduction of hydrogen repulsion. You can test this against crystal structure data. If you restore normal (i.e., hydrocarbon H) repulsion, keeping the electrostatic part, the model fails completely. On the other hand, is you delete the electrostatic part, keeping the zero repulsion, the fit to crystal data become only a little worse. What prevents the h-bond model from collapsing? Of course, it is the repulsion between the oxygens (in an O-H...O bond). What is the significance of the reduced H repulsion in the h-bond? Well this is what always happens when a bond forms. However, there normally is some residual repulsion, say K shell electrons, which prevents the bond from collapsing. Of course, H doesn't have an inner shell to prevent collapse, so maybe the zero repulsion can be rationalized. But there still is a proton there which needs to be considered. I believe that many elementary textbooks give a misleading picture when they describe the h-bond as primarily electrostatic, something akin to an ionic bond. Really the h-bond is more closely related to covalency, with reduced repulsion normally associated with the covalent bond. -Donald Williams -- Dr. Donald E. Williams email:dew01@xray5.chem.louisville.edu Department of Chemistry University of Louisville phone:502-852-5975 Louisville, KY 40292 fax: 502-852-8149 From bdavis@yorku.ca Fri Jul 25 22:13:30 1997 Received: from sungod.ccs.yorku.ca for bdavis@yorku.ca by www.ccl.net (8.8.3/950822.1) id VAA06367; Fri, 25 Jul 1997 21:30:53 -0400 (EDT) Received: from angel.phoenix.yorku.ca (y6JYuITMY9J7m/pFwd/t+IDJG6rto5ly@angel.phoenix.yorku.ca [130.63.236.44]) by sungod.ccs.yorku.ca (8.8.5/8.6.11) with ESMTP id VAA07174; Fri, 25 Jul 1997 21:30:53 -0400 (EDT) Received: from localhost (bdavis@localhost) by angel.phoenix.yorku.ca (8.8.5/8.6.12) with SMTP id VAA34509; Fri, 25 Jul 1997 21:30:53 -0400 X-Authentication-Warning: angel.phoenix.yorku.ca: bdavis owned process doing -bs Date: Fri, 25 Jul 1997 21:30:53 -0400 (EDT) From: Bill Davis X-Sender: bdavis@angel.phoenix.yorku.ca To: Lin Ping cc: CHEMISTRY@www.ccl.net Subject: Re: CCL:basis set of DFT calculation In-Reply-To: <33D93210.167E@chemvx.tamu.edu> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Ping: As part of my Ph.D. thesis, I reoptimized the Stevens-Basch-Krauss ECP basis sets for the main group elements boron to iodine. The results indicated that, while it is more "theoretically sound" to use a basis set optimized for a particular method (DFT, HF etc.), the results really do not change all that significantly. It is much more important in DFT to chose a good combination of exchange and correlation functionals to improve your predictions. I hope this helps! Regards, ************************************************************************* Dr. William M. Davis Phone: (416) 736-2100 ext. 77767 Dept. Of Chemistry Fax: (416) 736-5936 York University Email: bdavis@yorku.ca 4700 Keele St. North York, Ontario CANADA M3J 1P3 *************************************************************************