From sling@euclid.chem.washington.edu Thu Feb 24 02:02:58 1994 Received: from euclid.chem.washington.edu for sling@euclid.chem.washington.edu by www.ccl.net (8.6.4/930601.1506) id BAA20614; Thu, 24 Feb 1994 01:45:00 -0500 Received: by euclid.chem.washington.edu (AIX 3.2/UCB 5.64/4.03) id AA36308; Wed, 23 Feb 1994 22:48:33 -0800 Date: Wed, 23 Feb 1994 22:48:33 -0800 From: sling@euclid.chem.washington.edu (Song Ling) Message-Id: <9402240648.AA36308@euclid.chem.washington.edu> To: chemistry@ccl.net, noy@tci002.uibk.ac.at, topper@magnum.cooper.edu Subject: Re: CCL:solvation no. from MD & MC I read Prof. Topper's comments with high interest (honestly I don't know where/when the discussion got started. Just want to mention that one might want to try several different random number generators in the Monte Carlo calculations, to my knowledge there are some simple (not tricky) statistical tests and some random number generators pass some, others pass some different tests, hardly they pass a "global" set of tests. In trajectory calculations, the similar problems may arise in generating the initial conditions (random number generators are used). Whether the initial conditions are chosen on the tori (or the energy shell, say) only the phase space knows. If the system is not that chaotic, it will generally take a rather long to acheive the so called ergodicity. I remember what is quoted as said by Arnol'd: The understanding of 4 dimensional phase space is beyond the present mathematics. (Sorry, forget the source, would appreciate if someone let me know.) Song Ling From FLEMMING@dfhvax.nbi.dk Thu Feb 24 09:03:15 1994 Received: from nbivax for FLEMMING@dfhvax.nbi.dk by www.ccl.net (8.6.4/930601.1506) id IAA22804; Thu, 24 Feb 1994 08:28:10 -0500 From: Received: from DECNET-MAIL (FLEMMING@DFHVAX) by nbivax.nbi.dk (PMDF V4.2-13 #5783) id <01H99MFDO3TSAM6F8O@nbivax.nbi.dk>; Thu, 24 Feb 1994 14:28:00 +0100 Date: Thu, 24 Feb 1994 14:28:00 +0100 Subject: Conversion of SHELX output to ORTEP input ? To: chemistry@ccl.net Message-id: <01H99MFDRBKIAM6F8O@nbivax.nbi.dk> X-VMS-To: CCL MIME-version: 1.0 Content-transfer-encoding: 7BIT Dear Netters I'm looking for a program, which convert a SHELX (SHELXL-93) output file to an ORTEP input file. We are running SHELX on a SGI workstation and ORTEP on a Macintosh, so a program on any of those two platforms would be nice. Thank you. Flemming Steen Jorgensen flemming@dfhvax.nbi.dk From bob@bob.usuf2.usuhs.nnmc.navy.mil Thu Feb 24 11:03:23 1994 Received: from bob.usuf2.usuhs.nnmc.navy.mil for bob@bob.usuf2.usuhs.nnmc.navy.mil by www.ccl.net (8.6.4/930601.1506) id KAA24200; Thu, 24 Feb 1994 10:21:57 -0500 Received: by bob.usuf2.usuhs.nnmc.navy.mil; id AA18456; Thu, 24 Feb 1994 10:21:15 -0500 Date: Thu, 24 Feb 1994 10:21:15 -0500 From: Bob Williams Message-Id: <9402241521.AA18456@bob.usuf2.usuhs.nnmc.navy.mil> To: chemistry@ccl.net Subject: Density Functional Theory Dear Chemistry Net, We are interested in the relative merits of Density Functional Theory calculations, but we do not have access to appropriate software. What is the relative speed of DFT optimization and frequency calculations on a large molecule at modest levels of theory (compared to a similar RHF/4-31G job). Also, we would like to know something about the quality of the force matrix and frequencies produced by modest level DFT calculations, and about the transferability of scale factors. That is: how does the "cancelation of errors" produced by DFT compare to that from the 4-31G level. Thankyou in advance, Bob Williams, Dept. of Biochemitry, USUHS From B.S.Halstead@chemistry.hull.ac.uk Thu Feb 24 12:03:08 1994 Received: from sun2.nsfnet-relay.ac.uk for B.S.Halstead@chemistry.hull.ac.uk by www.ccl.net (8.6.4/930601.1506) id LAA24981; Thu, 24 Feb 1994 11:43:25 -0500 Via: uk.ac.hull; Thu, 24 Feb 1994 16:18:15 +0000 Received: from adelphi-bf0.ucc.hull.ac.uk by gilbert.ucc.hull.ac.uk with SMTP (PP) id <21260-0@gilbert.ucc.hull.ac.uk>; Thu, 24 Feb 1994 15:59:50 +0000 Received: from doshi.ucc.hull.ac.uk by humus.computer-centre.hull.ac.uk with SMTP (PP) id <02963-0@humus.computer-centre.hull.ac.uk>; Thu, 24 Feb 1994 16:19:29 +0000 From: ch4bsh Date: Thu, 24 Feb 94 16:19:09 GMT Message-Id: <14840.9402241619@humus.hull.ac.uk> To: chemistry@ccl.net Subject: AZT Derivatives Dear Netters I am attempting to calculate some properties of AZT derivatices using MINDO3. I will therefore be needing structural, thermodyanmic and biological activity data for various derivatives. If anybody has or knows the location of such data please let me know - This is only a final year project, if I have to find all the data by hand I probably won't have time to run any calculations. Thanks in advance Ben From mckelvey@Kodak.COM Thu Feb 24 12:04:42 1994 Received: from Kodak.COM for mckelvey@Kodak.COM by www.ccl.net (8.6.4/930601.1506) id LAA25005; Thu, 24 Feb 1994 11:45:41 -0500 From: Received: from NTPROF.DECnet MAIL11D_V3 by Kodak.COM (5.61+/2.1-Eastman Kodak) id AA00921; Thu, 24 Feb 94 11:45:47 -0500 Date: Thu, 24 Feb 94 11:45:45 -0500 Reply-To: mckelvey@Kodak.COM Message-Id: <9402241645.AA00921@Kodak.COM> To: osc@Kodak.COM Subject: SAN DIEGO ACS MEETING: SPECIAL TRIBUTE TO QCPE AND RICHARD W. COUNTS SAN DIEGO, CALIFORNIA AMERICAN CHEMICAL SOCIETY MEETING COMPUTERS IN CHEMISTRY SPECIAL SYMPOSIUM THE MORNING OF WEDNESDAY, MARCH 16, 1994 THE MARRIOTT HONORING THE QUANTUM CHEMISTRY PROGRAM EXCHANGE AND MR. RICHARD W. COUNTS "SOFTWARE SUPPORT DILEMMAS" SPEAKERS: "THE QCPE EXPERIMENT" DR. HARRISON SHULL, PROVOST NAVAL GRADUATE SCHOOL MONTEREY, CA 93943 "FUNDING COMPUTATIONAL CHEMISTRY IN THE 80'S AND 90'S" DR. NORMAN L. ALLINGER CHEMISTRY DEPARTMENT UNIVERSITY OF GEORGIA ATHENS, GA 30602 "WHYS AND WHY-NOTS OF COMMERCIALLY DISTRIBUTED SOFTWARE" DR. MICHAEL C. ZERNER QUANTUM THEORY PROJECT UNIVERSITY OF FLORIDA GAINSVILLE, FL 32606 "THIRTY YEARS OF THE SOFTWARE SUPPORT PROBLEM" MR. RICHARD W. COUNTS QUANTUM CHEMISTRY PROGRAM EXCHANGE INDIANA UNIVERSITY BLOOMINGTON, IN 47405 CO-SPONSORS: DIGITAL EQUIPMENT CO., FUJITSU COMPUTER SYSTEMS, EASTMAN KODAK CO., STERLING-WINTHROP PHARMACEUTICALS, AND STEWART COMPUTATIONAL CHEMISTRY From setlik@acsu.buffalo.edu Thu Feb 24 13:06:58 1994 Received: from lictor.acsu.buffalo.edu for setlik@acsu.buffalo.edu by www.ccl.net (8.6.4/930601.1506) id MAA25584; Thu, 24 Feb 1994 12:27:55 -0500 Received: from localhost (setlik@localhost) by lictor.acsu.buffalo.edu (8.6.4/8.6.4) id MAA04295 for CHEMISTRY@ccl.net; Thu, 24 Feb 1994 12:27:54 -0500 Date: Thu, 24 Feb 1994 12:27:54 -0500 From: "Robert F. Setlik" Message-Id: <199402241727.MAA04295@lictor.acsu.buffalo.edu> To: CHEMISTRY@ccl.net Subject: Fe-s charges Hi Netters, Does anyone have charges for a tetrahedral Fe-S complex. That is, something like the Iron cysteine complex found in ferredoxin. Also, has anyone done MD simulations on such a protein system. Any leeds would be appreciated. Rob Setlik .. From 21NBCJ@NPD.UFPE.BR Thu Feb 24 14:03:09 1994 Received: from npd1.npd.ufpe.br for 21NBCJ@NPD.UFPE.BR by www.ccl.net (8.6.4/930601.1506) id NAA26402; Thu, 24 Feb 1994 13:28:06 -0500 Received: from NPD.UFPE.BR by NPD.UFPE.BR (PMDF V4.2-11 #3818) id <01H99O6WKF6890NHPS@NPD.UFPE.BR>; Thu, 24 Feb 1994 15:26:49 -0300 Date: Thu, 24 Feb 1994 15:26:49 -0300 From: Nivan Bezerra <21NBCJ@NPD.UFPE.BR> Subject: He calculation To: Chemistry@ccl.net Message-id: <01H99O6WN3MQ90NHPS@NPD.UFPE.BR> X-VMS-To: IN%"Chemistry@ccl.net" MIME-version: 1.0 Content-type: TEXT/PLAIN; CHARSET=US-ASCII Content-transfer-encoding: 7BIT Hello netters, I am interested in CI calculation for He and isoeletronic series with STO basis sets. Can anyone tell me something about this calculation? Thanks in advance. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Nivan Bezerra da Costa Junior Fone: (081) 271-8440 Universidade Federal de Pernambuco Fax: (081) 271-8442 Centro de Ciencias Exatas e da natureza Departamento de Quimica Fundamental E-mail: Cidade Universitaria HEPNET: NPD1(47909)::21nbcj 50739 - Recife - PE INTERNET: nivan@vaxdqf.ufpe.br 21nbcj@npd1.ufpe.br ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ From yanke@qtp.ufl.edu Thu Feb 24 11:40:10 1994 Received: from qtp.ufl.edu for yanke@qtp.ufl.edu by www.ccl.net (8.6.4/930601.1506) id LAA24946; Thu, 24 Feb 1994 11:40:09 -0500 Received: from orange.qtp.ufl.edu (crunch.qtp.ufl.edu) by qtp.ufl.edu (4.0/4.11) id AA04803; Thu, 24 Feb 94 11:38:51 EST From: "Karen Yanke" Received: by orange.qtp.ufl.edu (4.1/4.11) id AA11684; Thu, 24 Feb 94 11:38:49 EST Date: Thu, 24 Feb 94 11:38:49 EST Message-Id: <9402241638.AA11684@orange.qtp.ufl.edu> To: jkl@ccl.net Cc: chemistry@ccl.net Subject: Applied Molecular Orbital Theory Workshop Ninth Florida Workshop on Applied Molecular Orbital Theory Dear Colleague: In your research, do many questions about molecular structure, spectra and reactivity arise? The Florida Quantum Theory Project offers the ninth edition of their popular one-week short course that will help you to answer the following questions: What is the structure of a proposed novel compound? What is the activation barrier for a potential reaction mechanism? How can I predict where to look for the vibrational or electronic spectra of a molecule to identify it? What are the structures, spectra and energetics of transient reaction intermediates? How can I assess the effect of adding a substituent on the color of a dye molecule without synthesis? Can I inexpensively screen functional molecules, such as drug derivatives, to identify the best prospects for success? How can computer graphics provide a new perspective on chemistry? How can I better understand and evaluate the quantum chemical analysis that accompanies more and more articles in the best chemical journals? If such questions are important to you, we invite you to attend our course on molecular orbital theory. The course is designed for scientists who are active researchers and recognize the potential for applying molecular orbital theory to molecules in order to provide information that is otherwise unavailable and for managers, supervisors and research directors who may be interested in an overview of recent advances in computational quantum chemistry and how they may be employed to enhance the productivity of their research unit. We invite you to learn the current developments in empirical potentials from Nigel Richards; semiempirical molecular orbital methods, such as AM1, SAM1, CNDO and INDO, from Michael Zerner; ab initio SCF theory from Yngve Ohrn; and correlated methods, many-body perturbation theory (MBPT; also known as MP) and coupled-cluster (CC) theory from Rod Bartlett; augmented with computer graphics by George Purvis of CAChe Scientific; and modern density functional theory (DFT). John Watts and Nevin Oliphant will coordinate the laboratory exercises. The staff's expertise spans the range from biomolecular applications, through organic chemistry, to the highest levels of ab initio methods and DFT. Applications are brought to life by employing a wide variety of graphics techniques to visualize the formation of chemical bonds or the potentials that molecules exert upon each other. Computer applications in chemistry are becoming essential. This is an opportunity for your research group to enhance your computational capabilities to provide results to complement the other instrumental techniques at your disposal. In addition to providing lecture material to assist you to select the right methods and to appreciate their limitations, the intent of this course is to provide "hands-on" experience with state-of-the-art computer programs executing on CAChe Scientific workstations and QTP computers. To take advantage of inexpensive plane fares that include a Saturday night stay, the course is scheduled for semester break on the campus of the University of Florida, with arrival on Sunday, May 1, and recommended departure on Sunday, May 8, 1994. Lectures are presented in the morning and early afternoon, with computer lab sessions later in the afternoon. Optionally, the computers are also available to participants in the evenings and all day Saturday, May 7, for additional work on applications. We also devote time to hear about your research problems and try to assist you in using theoretical methods to help solve them. Social events include a welcoming reception Sunday evening and dinners Monday, Wednesday and Friday that are held at the best restaurants in the area. Tuition, which includes room, dinners, coffee and detailed lecture notes, is at an inclusive $1250 per person. Enrollment will be limited to 25 participants, housed in single rooms at the Reitz Union on campus. Companions are invited to accompany a participant by payment of an additional $100 to cover the social affairs and room increment. Registration plus a check or purchase order payable to the University of Florida Research Foundation will be required before April 15, 1994, and should be sent directly to me at the Quantum Theory Project, P.O. Box 118435, University of Florida, Gainesville, FL 32611--8435. Please send your address via e-mail to Mrs. Yanke in my office and she will send you a registration form by mail or fax if you prefer (yanke@qtp.ufl.edu). We hope that you or some of your colleagues will find our course to be of interest. If we can provide any further information, please call us. Sincerely, Rodney J. Bartlett Graduate Research Professor of Chemistry and Physics From pat@mercury.aichem.arizona.edu Thu Feb 24 15:03:11 1994 Received: from mercury.aichem.arizona.edu for pat@mercury.aichem.arizona.edu by www.ccl.net (8.6.4/930601.1506) id OAA27133; Thu, 24 Feb 1994 14:23:46 -0500 Received: by mercury.aichem.arizona.edu (5.57/Ultrix3.0-C) id AA15988; Thu, 24 Feb 94 12:15:07 -0700 Date: Thu, 24 Feb 1994 12:13:07 -0700 (MST) From: Pat Walters Subject: Re: CCL:Collaborative software development To: chemistry@ccl.net In-Reply-To: Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Our file conversion program Babel provides another example of collaborative development via the internet. We designed the program with an open architecture which facilitates the easy inclusion of new file formats. In addition we have provided a "Babel Developer's Guide" which provides step by step instructions on how to add new file formats to the program. Adding a new reader or writer routine typically requires less than 50 lines of C code. When we released the program in December it supported 16 file formats. Now, due to submissions from around the world, Babel supports 35 file formats and the number is still growing. In addition to acting as file conversion program Babel can be compiled into a library which can provide a variety of routines including : - assignment of bonds - assignment of hybridized atom types - assignment of bond orders - determination of interatomic distances, bond angles and torsion angles - conversion between internal, fractional and Cartesian coordinates. - addition and deletion of hydrogens - a number of routines for vector manipulation The program runs under Unix, MS-DOS, and the Mac. I've heard that there are also ports to Atari and Open VMS, but I haven't seen them. We are currently using the Babel library as the core for our development efforts, and we plan to release additions to Babel and the library in the coming months. There will be two presentations on Babel (#36 and #37 in the Division of Chemical Information) at the San Diego ACS meeting. For more information on babel finger babel@mercury.aichem.arizona.edu or send mail to babel@mercury.aichem.arizona.edu _________________________________________________________________________ Pat Walters pat@mercury.aichem.arizona.edu Graduate Student Laboratory for Artificial Intelligence in Chemistry * Dept of Chemistry * * * University of Arizona, Tucson AZ 85721 * * * Voice : 602-621-6334 FAX : 602-621-8407 *** "At least it's a dry heat" * _______________________________________________________*__________________ From st-amant@theory.chem.uottawa.ca Thu Feb 24 16:04:30 1994 Received: from theory.chem.uottawa.ca for st-amant@theory.chem.uottawa.ca by www.ccl.net (8.6.4/930601.1506) id QAA28403; Thu, 24 Feb 1994 16:00:44 -0500 Received: by theory.chem.uottawa.ca (AIX 3.2/UCB 5.64/4.03) id AA18394; Thu, 24 Feb 1994 15:59:57 -0500 Date: Thu, 24 Feb 1994 15:59:57 -0500 From: st-amant@theory.chem.uottawa.ca (alain st-amant) Message-Id: <9402242059.AA18394@theory.chem.uottawa.ca> To: CHEMISTRY@ccl.net Subject: DFT software Dear Netters, As I mentioned a while back, I was working on some DFT code that I'd make available to other computational chemists free of charge. Well, it's finally ready now. The program, DeFT, can be obtained via ftp. However, it is NOT public domain software, and we'd ask you to observe the copyright and license agreement that come with the source code. All we ask in return is that all improvements be sent back to me so that we can make your improvements freely available to others. Such contributors will of course be appropriately recognized. The code can basically locate local minima, locate transition states, perform vibrational analyses, with the use of analytic first derivatives. Sorry, no analytic second derivatives. DeFT uses gaussian functions and is therefore quite similar to DGauss. Both LSDA and NLSDA calculations can be performed. The code can be obtained by ftp'ing theory.chem.uottawa.ca (137.122.43.156) with the username "DeFT_ftp". The filename is "DeFT_tarfile.Z", and it will be there in your home directory. However, to add an extra level of security, and to help me keep track of how many people are using the code, a password is required. People can obtain the password by e-mailing the following address: request@theory.chem.uottawa.ca I will try to e-mail the password back as promptly as possible (hopefully, this should be within an hour or two, at worst, overnight if the request is sent late in the day). The password will remain valid for several days. The code, documentation, and sample inputs and outputs, once tar'ed and compressed, come out to about 800 kilobytes. Hopefully, the code will be of use to some, and improvements can be added by its new users. Alain St-Amant Department of Chemistry University of Ottawa From JFO555F%SMSVMA.BITNET@phem3.acs.ohio-state.edu Thu Feb 24 17:03:30 1994 Received: from phem3 for JFO555F%SMSVMA.BITNET@phem3.acs.ohio-state.edu by www.ccl.net (8.6.4/930601.1506) id QAA28514; Thu, 24 Feb 1994 16:09:26 -0500 Received: from SMSVMA.BITNET (MAILER@SMSVMA) by phem3.acs.ohio-state.edu (PMDF V4.2-13 #3557) id <01H99PYOXBF49EF148@phem3.acs.ohio-state.edu>; Thu, 24 Feb 1994 16:09:17 EST Received: from SMSVMA (JFO555F) by SMSVMA.BITNET (Mailer R2.08 R208004) with BSMTP id 0817; Thu, 24 Feb 94 14:44:31 CST Date: Thu, 24 Feb 1994 14:43:35 -0600 (CST) From: "Jim O'Brien" Subject: Energies in Td Complexes To: chemistry@ccl.net Message-id: <01H99PYQR84E9EF148@phem3.acs.ohio-state.edu> Content-transfer-encoding: 7BIT To read about energies in Td complexes you might try Chapter 9 in the third edition of F. A. Cotton, Chemical Applications of Group Theory. From leboeuf@CERCA.UMontreal.CA Thu Feb 24 17:07:37 1994 Received: from condor.CC.UMontreal.CA for leboeuf@CERCA.UMontreal.CA by www.ccl.net (8.6.4/930601.1506) id QAA28613; Thu, 24 Feb 1994 16:26:11 -0500 From: Received: from proust.CERCA.UMontreal.CA by condor.CC.UMontreal.CA with SMTP id AA29128 (5.65c/IDA-1.4.4 for chemistry@ccl.net); Thu, 24 Feb 1994 16:23:17 -0500 Received: from pellan.CERCA.UMontreal.CA by proust.CERCA.UMontreal.CA (920330.SGI/5.17) id AA21085; Thu, 24 Feb 94 16:24:01 -0500 Received: by pellan.CERCA.UMontreal.CA (920330.SGI/5.17) id AA12350; Thu, 24 Feb 94 16:24:00 -0500 Message-Id: <9402242124.AA12350@pellan.CERCA.UMontreal.CA> Subject: optimal distribution of charges on sphere To: chemistry@ccl.net Date: Thu, 24 Feb 1994 16:24:00 -0500 (EST) Cc: leboeuf@CERCA.UMontreal.CA (Martin Leboeuf), salahub@ERE.UMontreal.CA X-Mailer: ELM [version 2.4 PL23] Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Length: 1078 Dear CCLers, A computational fluid dynamics friend has asked if we chemists know anything about the distribution of points (charges) on a sphere. (He is interested in bubbles) I remember seeing some papers on this question but can't place them. There is some work in theoretical inorganic chemistry and some demonstrations of the optimal configurations for quite high N (the number of points). Any clues? Please reply to leboeuf@cerca.umontreal.ca and Martin Leboeuf or I will summarize to the net, if it seems appropriate. Dennis Salahub -- ************************************************************ * Dennis Salahub SALAHUB@ERE.UMONTREAL.CA * * Departement de chimie Tel. (514) 343-6755 * * Universite de Montreal Fax (514) 343-2468 * * C.P. 6128, Succ. A * * Montreal, Quebec H3C 3J7 * * Canada * ************************************************************ From JSMCM@jazz.ucc.uno.edu Thu Feb 24 17:12:08 1994 Received: from jazz.ucc.uno.edu for JSMCM@jazz.ucc.uno.edu by www.ccl.net (8.6.4/930601.1506) id QAA28828; Thu, 24 Feb 1994 16:52:54 -0500 Received: from jazz.ucc.uno.edu by jazz.ucc.uno.edu (PMDF #2820 ) id <01H99P1IM1KC8X4FIS@jazz.ucc.uno.edu>; Thu, 24 Feb 1994 15:51:40 CST Date: 24 Feb 1994 15:51:40 -0600 (CST) From: JORGE Subject: Density Functional Theory To: chemistry@ccl.net Cc: bob@bob.usuf2.usuhs.nnmc.navy.mil Message-id: <01H99P1IM1KE8X4FIS@jazz.ucc.uno.edu> X-VMS-To: IN%"chemistry@ccl.net" X-VMS-Cc: IN%"bob@bob.usuf2.usuhs.nnmc.navy.mil",JSMCM MIME-version: 1.0 Content-type: TEXT/PLAIN; CHARSET=US-ASCII Content-transfer-encoding: 7BIT Here my answers to Bob Williams. Enjoy! >We are interested in the relative merits of >Density Functional Theory calculations, >but we do not have access to appropriate software. The best merit, as our group is concerned, is that we can get better energetics (atomization energies) than MP4SDTQ/6-311+G** or QCISD(T)/6-311G**. The lowest level of theory that improves the DFT is MP4SDTQ/6-311(2df,p). I don't mean by this that we should not continue developing sophisticated ab initio methods. We certainly need then to continue the development of better functionals. We used Perdew-Wang functionals for this particular comparison with a basis set with double zeta valence plus polarization functions on all atoms (like 6-31G**).(preprints on request) >What is the relative speed of DFT optimization >and frequency calculations on a large molecule >at modest levels of theory >(compared to a similar RHF/4-31G job). The problem (actually advantage) is that DFT calculations contain almost all of the correlation portion missing in HF; therefore, it requires of polarization functions for its correct calculation. Calculations without polarization functions yield qualitatively wrong results (similar situation would happen doing MP4/4-31G). Basically DFT scales as N**3 as opposed to HF who scales as N**4. For large systems both exponents decrease. For small systems, it is commom that the N**3 is not that advantage because the numerical integrations involved in DFT codes. When you have ten or more heavy atoms DFT is the only choice for good energetics. With respect to second derivatives, until G92/DFT we (in UNO) did not have an analytical procedure to calculate second derivatives. The programs I used have numerical second derivatives and they were really slow, as they are also with other ab initio methods using numerical second derivatives. We hope that analytical second derivatives for DFT methods became common very soon. >Also, we would like to know something about >the quality of the force matrix and frequencies >produced by modest level DFT calculations, There is no problem in the quality of results but the strong limiting fact was that the numerical second derivatives were too slow. (as I told you I have not tried yet G92/DFT for frequency calculations). Finally, the modest DFT calculation you want to try have to use a 6-31G** basis set or equivalent. The advantage is that you don't need a bigger basis because the quality of the calculation at that point is given by the functional you choose any further improvement would have to done to the functional. >and about the transferability of scale factors. >That is: how does the "cancelation of errors" produced by >DFT compare to that from the 4-31G level. Being DFT a more precise tool than [HF/]4-31 level, the errors are much smaller, therefore DFT do not require of such an (big) error cancellation. However, I am not very sure to what error cancellations you referring to. Hope this help Jorge M. Seminario jsmcm@uno.edu From billys@chmboy.srl.ford.com Thu Feb 24 19:03:14 1994 Received: from smail.srl.ford.com for billys@chmboy.srl.ford.com by www.ccl.net (8.6.4/930601.1506) id SAA00378; Thu, 24 Feb 1994 18:19:48 -0500 Received: from chmboy.srl.ford.com by smail.srl.ford.com with SMTP ; Thu, 24 Feb 94 18:18:53 EST Received: by chmboy.srl.ford.com (AIX 3.2/UCB 5.64/4.03) id AA15611; Thu, 24 Feb 1994 18:08:38 -0500 From: billys@chmboy.srl.ford.com (Bill Schneider) Message-Id: <9402242308.AA15611@chmboy.srl.ford.com> To: chemistry@ccl.net Subject: Re: CCL:Symmetry label for molecular states In-Reply-To: (Your message of Wed, 23 Feb 94 11:57:39 N.) <350*/RFC-822=pis(u)diez(a)cpd.uva.es/OU=cpd/O=uva/PRMD=iris/ADMD=mensatex/C=es/@MHS> Date: Thu, 24 Feb 94 11:59:28 -0500 Sorry for replying to the net, but direct mail failed. There is only one triplet state that arises from the configuration (t2)^2. It is 3T_1. The other states are 1A_1, 1E, and 1T_2. From Hund's rules the 3T_1 would be the lowest energy. When coupling two equivalent electrons, you must use the antisymmetric direct product to obtain the triplet functions, and the symmetric direct product to obtain the singlet. Landau and Lifshitz has more details. Bill Schneider Ford Motor Co.