From chemistry-request@www.ccl.net Tue Aug 11 01:02:09 1998 Received: from mailsrv.rz.fh-merseburg.de (mailsrv.rz.fh-merseburg.de [149.205.18.1]) by www.ccl.net (8.8.3/8.8.6/OSC/CCL 1.0) with ESMTP id BAA18564 Tue, 11 Aug 1998 01:02:09 -0400 (EDT) Received: (from nowak@localhost) by mailsrv.rz.fh-merseburg.de (8.8.8/8.8.7) id HAA00867 for CHEMISTRY@www.ccl.net; Tue, 11 Aug 1998 07:05:08 +0200 (METDST) Date: Tue, 11 Aug 1998 07:05:08 +0200 (METDST) From: Thomas Nowak Message-Id: <199808110505.HAA00867@mailsrv.rz.fh-merseburg.de> To: CHEMISTRY@www.ccl.net Subject: CCL:MM3 parameters dear all, i'm looking for suitable parameters for the mm3 force field to model organophosphourus(iii) ligands, expecially phosphites (f.i. trimethyl -> P(OMe)3, triphenyl -> P(OPh)3), but also phosphines (f.i. trimethyl -> PMe3; triphenyl -> PPh3). Although the latter should be included in the standard parametrization, no suitable set of parameters describing the phosphites are found. I my resarch the TINKER package was used. Is there anybody out there who can give me some pointers to the needed parameters or even better, who has made her/his own set of parameters by hand. best regards Thomas From chemistry-request@www.ccl.net Tue Aug 11 04:20:29 1998 Received: from theo1.theochem.tu-muenchen.de (theo2.theochem.tu-muenchen.de [129.187.191.1]) by www.ccl.net (8.8.3/8.8.6/OSC/CCL 1.0) with SMTP id EAA19200 Tue, 11 Aug 1998 04:20:28 -0400 (EDT) Received: from theo350.theochem.tu-muenchen.de (theo350.theochem.tu-muenchen.de [129.187.157.44]) by theo1.theochem.tu-muenchen.de (950413.SGI.8.6.12/950213.SGI.AUTOCF) via ESMTP id KAA21246 for <@theo1.theochem.tu-muenchen.de:CHEMISTRY@www.ccl.net>; Tue, 11 Aug 1998 10:20:00 +0200 Received: (from gisdakis@localhost) by theo350.theochem.tu-muenchen.de (950413.SGI.8.6.12/950213.SGI.AUTOCF) id KAA09444 for CHEMISTRY@www.ccl.net; Tue, 11 Aug 1998 10:19:59 +0200 From: "Philip Gisdakis" Message-Id: <9808111020.ZM9442@theo350.theochem.tu-muenchen.de> Date: Tue, 11 Aug 1998 10:19:59 -0600 X-Mailer: Z-Mail (3.2.3 08feb96 MediaMail) To: CHEMISTRY@www.ccl.net Subject: Visualize NMR Calculations? Hi everybody, is there a (free?) tool to simulate a NMR spectra from calculated (Gaussian) chemical shifts? We want to use it for educational purposes. Thank you Philip -- Philip Gisdakis o-----------------------------------------------------------------o / Philip Gisdakis gisdakis@theochem.tu-muenchen.de / \ / Theoretical Chemistry Phone: +49 +89 289 13618 (Univ.) / o /Technical University of Munich 67908232 (Privat) / / / Lichtenbergstrasse 4 / / / D - 85747 Garching / / o-----------------------------------------------------------------o / \ \ / o-----------------------------------------------------------------o From chemistry-request@www.ccl.net Tue Aug 11 07:12:22 1998 Received: from cammsg1.caos.kun.nl (cammsg1.caos.kun.nl [131.174.88.1]) by www.ccl.net (8.8.3/8.8.6/OSC/CCL 1.0) with SMTP id HAA19714 Tue, 11 Aug 1998 07:12:21 -0400 (EDT) Received: from schaft by cammsg1.caos.kun.nl with local id 0z6CLl-0007PP-00; Tue, 11 Aug 1998 13:12:21 +0200 Subject: Is there a need for a Calculated Structures Database ? To: chemistry@www.ccl.net Date: Tue, 11 Aug 1998 13:12:21 +0200 (MDT) X-Mailer: ELM [version 2.4 PL25] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Message-Id: From: Gijs Schaftenaar A Calculated Structures Database. --------------------------------- Not more than perhaps a decade ago, Computational Chemistry used to be the realm of Quantum Chemists with access to a supercomputer. Computer resources usually restricted calculations to small molecules. Nowadays this situation has changed drastically. With the continuous speedup of computer hardware, calculations on chemically interesting systems have become tractable to the bench chemist and the study of short lived intermediates and transition states, often inaccessible to experiment, have become common practice. The Computational Chemistry community has steadily grown and broadened and does no longer exist of pure specialists only. The Computational Chemistry List (CCL; URL: http://www.ccl.net/ccl/welcome.html), a Web site and an e-mail exploder which allows computational chemistry researchers from around the world to exchange information and experiences is an important commucation channel. With so many structures being calculated, the need for a (comprehensive) database of calculated structures has been voiced a number of times on the Computational Chemistry List. The Carnegie-Mellon Quantum Chemistry Archive, created by Prof. Pople's group for users of the Gaussian package, has been an attempt to set up such a database. However, for a number of reasons this database has never been very successful. Gaussian users could (can) contribute to this database by sending a routinely created archive file by surface mail to the curators of the database, the Chemistry Publishing Unit of Carnegie-Mellon University. Access to the database can only be obtained by purchasing it together with its dedicated software. But for a database to be successful, ease of contributing to it and ease of data retrieval are determing factors. The CAOS/CAMM Center, the Dutch national academic Center for the Application of Information Technology in Chemistry, is exploring the possibility to create, curate and maintain a comprehensive archive of calculated structures at both the ab-initio and semi-empirical level with emphasis on co-ordinate data. Contributions to this database should be submitable via e-mail and/or the World Wide Web. We intend to automate submission by incorporating a submission form into our popular quantum chemistry visualisation tool MOLDEN, which interfaces not only to Gaussian but to a range of other Ab Initio and semi-empirical codes. MOLDEN currently has a distribution of over 800 copies world wide and is freely available to academic researchers making (coordinate) data contibution an easy task. Access to the database will be given via the World Wide Web and added value is intended by linking it to other chemically oriented databases, in particular to the Quantum Chemistry Literature Database (QCLDB). The Gaussian archive file format might serve as a starting point for the definition of a new and richer format which would include semi-empirical calculations and links to literature and other chemical databases. Because the Center maintains the MOLDEN software, adaptions to deal with a new data format can easily be implemented and distributed. With this message we try to measure the potential (mental) support for such an initiative and to determine the willingness among computational chemists to contribute data to the intended database of calculated structures. This will help us to determine if the allocation of computational and human resources to this effort can meet with sufficient enthousiasm to start. For the database to reach the critical mass needed to become a successful operation, in addition to the processing of existing data sources, the active contribution of data from many private sources is necessary. Therefor your answer to the following questions is very much appreciated. 1. Do you think that the proposed initiative is advisable and/or needed ? 2. Would you be willing to contribute data to the proposed database, using either a MOLDEN form or a WEB based form? Your answers are welcomed at the e-mail addresses: schaft@caos.kun.nl (Gijs Schaftenaar, Computational Chemist and MOLDEN author CAOS/CAMM Center.) or noordik@caos.kun.nl (Jan Noordik, Director CAOS/CAMM Center) ------------------+-----------------------+------------------------------ CAOS/CAMM Center Phone: +31(0)24-3653386 University of Nijmegen +31(0)24-3653391(secr.) Toernooiveld 1 Fax: +31(0)24-3652977 6525 ED Nijmegen e-mail: post@caos.kun.nl The Netherlands URL: http://www.caos.kun.nl ------------------+-----------------------+------------------------------ The CAOS/CAMM Center is the Dutch Academic Facility for the Application of Information Technology in: Organic Chemistry: CAOS Computational Chemistry, Molecular Modeling, 3D Databases: CAMM Bioinformatics: CAMMSA It is also the Dutch National Node in EMBnet and GDB. ------------------+-----------------------+------------------------------ From chemistry-request@www.ccl.net Tue Aug 11 10:44:51 1998 Received: from Raven.und.ac.za ([146.230.128.50]) by www.ccl.net (8.8.3/8.8.6/OSC/CCL 1.0) with ESMTP id KAA21154 Tue, 11 Aug 1998 10:44:23 -0400 (EDT) Received: from gwise-smtp.und.ac.za (GWise-SMTP.und.ac.za [146.230.128.63]) by Raven.und.ac.za (8.8.3/8.7.3) with SMTP id QAB16474 for ; Tue, 11 Aug 1998 16:38:22 +0200 (SAT) Received: from UND-Message_Server by gwise-smtp.und.ac.za with Novell_GroupWise; Tue, 11 Aug 1998 09:42:02 +0300 Message-Id: X-Mailer: Novell GroupWise 5.2 Date: Tue, 11 Aug 1998 09:46:58 +0300 From: "Gert Kruger" To: chemistry@www.ccl.net Subject: CCL:G94W on DEC Alpha for NT Dear CCL, We are investigating buying either a Digital Personal Workstation for Windows NT or a the equivalent in Unix (www.dec.com). The NT version is considerably cheaper and the suppliers claim that the two machines perform equal. Gaussian however, does not supply a version for Alpa NT machines, and one would have to use additional software (which is standard with NT 5) in order to run normal NT software. I would appreciate any comments on: 1. The performance of the 2 machines. 2. The use of Gaussian for Windows software on the DEC Alpha machine. How does it compare with the Unix software. 3. Any other hints. I will summarise the info. Best wishes Gert Kruger ___________________________________ Dr HG Kruger, Chemistry, University of Natal P.O. box 18091, Dalbridge 4014 Durban, South Africa. tel: +27-31-2603090 fax: +27-31-2603091 email: kruger@scifs1.und.ac.za ___________________________________ From chemistry-request@www.ccl.net Tue Aug 11 13:32:27 1998 Received: from alchemy.chem.utoronto.ca (alchemy.chem.utoronto.ca [142.150.224.224]) by www.ccl.net (8.8.3/8.8.6/OSC/CCL 1.0) with ESMTP id NAA22811 Tue, 11 Aug 1998 13:32:26 -0400 (EDT) Received: (from elewars@localhost) by alchemy.chem.utoronto.ca (8.7.4/8.7.3) id NAA26595 for chemistry@www.ccl.net; Tue, 11 Aug 1998 13:32:26 -0400 (EDT) Date: Tue, 11 Aug 1998 13:32:26 -0400 (EDT) From: "E. Lewars" Message-Id: <199808111732.NAA26595@alchemy.chem.utoronto.ca> To: chemistry@www.ccl.net Subject: NEG ACTIV E: SUMMARY Tuesday 1998 August 11 Hello, Thanks to all who replied to my question about negative activation energies: P-O Norby, A. Korkin, S. Abrash, M. Hohmann, J. Vill'ai Fre, l. Burke, A. Shusterman and J. Perry (I hope I haven't missed any one). The question was: Sometimes one gets a _negative_ value for an activation E. For example O O \\ \\... C---O C---O | | -----> . . transition state --> CO2 + N2 N===N . . ..... N====N -297.56194 h -297.56281 h activ E = -0.00087 h = -2.28 kJ/mol G2(MP2) energies Sometimes one gets a negative value with and without the ZPE corection. Is there any special theoretical significance to such "impossible" activation E's? Or can one just say that (since not much below zero) they are compatible with a low positive barrier? Thanks E. Lewars ============== I now see that -ve activation E's can easily be obtained if the barrier is low; they are essentially just errors caused by errors in the ZPE, or, in the case of single-point calcs on a structure optimized at a lower level (which is what G2-type calcs are), errors can arise from the fact that the lower-level statonary points will not be exactly the max and min on the higher-level PES. . . . . .x . x . . | . | .. . | . .~. | -ve ~ . | . ./|\ . | /|\ . \|/ . .| . \|/ | . ----------- x . x | +ve . . |. . | . . ________|_. . | ~ . ~ . I think this is the cause in this case; as others pointed out (SUMMARY BELOW), there can be other causes of neg activ E's, like precomplexation (van der Waals complexes) and etc (J Chem Phys, 1997, 107, 7266), and when the Arrhenius A factor dominates the exponential factor (deltaE ~- 0). ------------ SUMMARY OF RESPONSES: 3-AUG-1998 17:36:45.52 >From: IN%"peon@medchem.dfh.dk" "Per-Ola Norrby" To: IN%"elewars@alchemy.chem.utoronto.ca" "E. Lewars" Subj: CCL:NEGATIVE ACTIVATION E's Well, in this case, it just means you use an improper method... The G2 methods are extrapolation methods that depend on the geometry being well represented by a low level method. In this case, you are using HF/6-31G* to locate the TS geometry, I guess this is the source of your problem. If you use a method where you calculate the energy at the same level as your geometry, this type of problem should disappear (there are other possible sources of apparent negative TS energies, like precomplexing, but that should not apply in your case). For some good possible choices for geometry optimization levels, I'd suggest MP2/6-311G**, or B3LYP/6-31G* (depending on your computational resources and/or theological leaning). The G2 methods were developed to calculate VERY accurate heats of formation, but in general, I wouldn't recommend them for TS calculations (just a personal opinion, I'd like to hear if there is a concensus on this). Regards, Per-Ola Norrby ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Per-Ola Norrby, peon@medchem.dfh.dk Royal Danish School of Pharmacy, Dept. of Med. Chem. Universitetsparken 2, DK-2100 Copenhagen, Denmark Tel: +45-35376777-506, +45-35370850, fax +45-35372209 ============= >From: IN%"r40757@email.mot.com" "Anatoli Korkin" To: IN%"elewars@alchemy.chem.utoronto.ca" "E. Lewars", IN%"chemistry@infome ister.ccl.net" "chemistry@www.ccl.net", IN%"bartlett@qtp.ufl.edu" "Rod Bartlett" Subj: CCL:NEGATIVE ACTIVATION E's Negative activition energies you may get in two cases (may be someone knows more): 1) There is an intermediate complex between reagents and a TS. In this case everything is "normal". Some SN2 gas phase reactions have "negative" activitations energies. This led first to a suspecion among experimentalists, who studied these reactions in solutions, that theory was wrong, but later this result has been confirmed for gas phase reactions. 2) For very low barriers you may get negative activation energies, if you do (higher level) single point calculations using geometries optimized at another (lower correlation) approach. If you optimize a TS and reagents at the same level and there is no an intemediate mimimum on a reaction pathway you should not get your electronic energy for TS lower than that one for reagents. Of course, zero point energy correction may change the sign of the barrier, if it is very small (e.g. 1 kcal/mol or lower). Anyway at such low barriers a conventional transition state theory is hardly applicable, and a dynamical treatment is required. Regards, Anatoli P.S. We have a paper on CN2O2 species including the complex below. An activation energy we got at CCSD(T)/TZP//MBPT(3)/6-31G* was 0.5 kcal/mol before and -0.3 kcal/mol after ZPE correction. ----------- ****************************************************************** Anatoli A. Korkin, Ph.D Predictive Engineering Lab Computational Chemist Semiconductor Products Sector Motorola Inc., MD M360 Tel: (602) 655-3171 2200 W. Broadway Road Fax: (602) 655-5013 Mesa AZ 85202 E.mail: r40757@email.mot.com ******************************************************************* X-Sender: sabrash@facstaff.richmond.edu Subject: Re: CCL:NEGATIVE ACTIVATION E's Dear Professor Lewars, I cannot give you the answer for the theoretical case, but can explain t he significance for experimentally determined negative activation energies. The rate constant for a reaction in the Arrhenius model is given by k = A(T) exp (-Ea/RT). Because the activation energy temperature dependence typically swamps that due to the preexponential factor, typical Arrhenius analyses ignore the temperature dependence of the A term. However when Ea is for all practical purposes zero, then the temperature dependence is that of the A factor which tends to increase with decreasing temperature. This therefore appears as a negative activation energy. Such reactions are better fit by the equation k = AT^m exp(-E0/RT), where E0 is equivalent to the zero k activation energy. Best regards, Sam Abrash >============== Sam Abrash Associate Professor Department of Chemistry University of Richmond Richmond, VA 23174 (804) 289-8248 Fax: (804)289-8482 sabrash@richmond.edu "I believe in the open mind, but not so open your brain falls out." ================== Subject: neg. E act To: elewars@alchemy.chem.utoronto.ca Date: Mon, 3 Aug 1998 15:10:42 -0500 (EDT) X-Mailer: ELM [version 2.4 PL20] Hi! Negative activation energies can result - from ZPE corrections or - if you derive your relative energies from single point calculations and the geometries used are not good enough (i.e. the geometries at the level of opt and at the level of single points deviate considerably) If you get a "neg. activation energy" at the level of geometry opt., something is wrong. I suggest to look at the vector of the imaginary frequency first. If it seems to be ok check the transition state with an IRC (intrinsic reaction coordinate) calculation. Good luck, Matthias M. Hohmann ============ Jordi Villa i Freixa Department of Chemistry University of Southern California Los Angeles, CA, USA, 90089-1062 Tlf: 1-(213)-740 7671 Fax: 1-(213)-740 2701 villa@mutant.usc.edu http://t1.chem.umn.edu/~villa -What you call "activation energy" is, in fact, an energy barrier. Activation energy is a kinetic concept that comes from the Arrhenius equation. -Probably the small negative value you obtain is due to the G2 method, where you are not exploring exactly a concrete potential energy surface, but adding the contributions of several corrections to the initial energy surface. -The example you are posting is really interesting because of the low barrier (in your case is negative, but I guess that using only the non-G2-corrected surface the barrier would be positive or zero). This means that considering the barrier to be the given value could lend you to an error when trying to understand kinetic experimental results, for example. The location of only the saddle point on this reaction will not be enough to understand the dynamics of the system, and a treatment with variational transition state theory could be necessary. If you want more information about the dynamic treatment of this kind of barrierless or almost barrierless reactions take a look to: J. Chem. Phys. 1997, 107, 7266 J. Am. Chem. Soc. 1998, 120, 5559. I hope this will help Yours Jordi =========== Aug 3 Luke A. Burke (31) impos tsCommand: Read MessageMessage 5/17 from Luke A. Burke Aug 3 '98 at 6:59 pm Date: Mon, 3 Aug 1998 18:59:03 -0400 X-Mailer: Z-Mail (3.2.3 08feb96 MediaMail) To: elewars@alchemy.chem.utoronto.ca Subject: impos ts Mime-Version: 1.0 ............... If your structure is indeed a ts, then there must be a minimum and another ts between your drawn structures. You did not give the geometry of the ts but I suspect that there is the involvement of van der Waals complexes. BTW, in the history of ts oddities, I found a reaction (rotation) where the Ea >0, but Ha<0 and Ga<0. Salut, de koste en de wind van achter, en de steenweg tot huis toe (plat Leuvense) Luke -- Luke Anthony Burke tel:609-225-6158 (-6142) Professor and Chair, fax:609-225-6506 Rutgers University burke@camden.rutgers.edu Camden, NJ 08102, USA http://camchem.rutgers.edu/~burke ============== Alan Shusterman Date: 03 Aug 98 13:42:35 PDT Subject: Re: CCL:NEGATIVE ACTIVATION E's I noticed that your negative barrier results from comparison of = G2(MP2) energies. I'm not very familiar with the G2 model, but I = was wondering what model was used to identify the reactant minimum = and transition state, and did this model give a negative or = positive barrier? Alan ---------------- Alan Shusterman Department of Chemistry Reed College Portland, OR www.reed.edu/~alan ============================== Aug 3 Jason K. Perry (31) Re: CCL:NEGATIVE ACTIVATION E'sCommand: Read MessageMessage 8/17 from Jason K. Perry Aug 3 '98 at 1:53 pm Date: Mon, 3 Aug 1998 13:53:36 -0700 (PDT) To: "E. Lewars" Subject: Re: CCL:NEGATIVE ACTIVATION E's > Sometimes one gets a negative value with and without the ZPE corection. The reason you're seeing negative activation energies is because with the G2 method you are calculating the geometry at one level and reporting an energy at a different level. At the level that the geometry was determined it is most certainly the case that the activation barrier is positive. For example, if I calculate geometries for reactant, product and transition state at the HF/6-31G** level, the transition state will be correct for that level and show a positive barrier. If I then do single point B3LYP/6-31G** calculations using those HF/6-31G** geometries the transition state will not be correct for the new level, and thus there is no guarantee that the barrier will be positive. Jason Perry First Principles Research, Inc. ================ From chemistry-request@www.ccl.net Tue Aug 11 17:51:40 1998 Received: from chad.scs.uiuc.edu (chad.scs.uiuc.edu [130.126.224.241]) by www.ccl.net (8.8.3/8.8.6/OSC/CCL 1.0) with ESMTP id RAA26228 Tue, 11 Aug 1998 17:51:39 -0400 (EDT) Received: from localhost (godbout@localhost) by chad.scs.uiuc.edu (AIX4.2/UCB 8.7/8.7) with SMTP id QAA17170; Tue, 11 Aug 1998 16:38:27 -0500 (CDT) Date: Tue, 11 Aug 1998 16:38:27 -0500 (CDT) From: Nathalie Godbout To: chemistry@www.ccl.net cc: "Prof. Eric Oldfield" Subject: G94 cube file units and Cerius2 Message-ID: Dear computational chemists, I have a question concerning electron density surfaces calculated with G94 (cube=density), the use of Cerius2 to display these surfaces and units. According to the cube file I have calculated, the density values range from 0 to 27 electrons/bohr^3 (I think). When I use the Gaussian interface in Cerius2 to display the surface, the property range displayed is 0 to 182. Using the conversion factor between electrons/bohr^3 and electrons/angstrom^3 (6.75), I get the the property range displayed in Cerius2. To make sure this was correct, I created a 3X3X3 cube with only one non-zero value, namely 1.0. When I display this cube in Cerius2, I expected the property to range from 0 to 6.75 e/A^3. I get that the range is 0 to 1.0. Further, I am able to display electron density values between 0.0 and 1.0. Are the values in the cube file multiplied by a conversion factor or are values extra/intrapolated? I have also the same question for the electrostatic potential for which there is also a difference the cube file values and the displayed values. I will summarize. Thank you for your help. Nathalie -------------------------------------------- | Nathalie Godbout | | University of Illinois at Urbana-Champaign | | 600 S. Goodwin Av. Box 23.6 | | Urbana, IL 61801 | -------------------------------------------- From chemistry-request@www.ccl.net Tue Aug 11 18:36:49 1998 Received: from hotmail.com (f128.hotmail.com [207.82.251.7]) by www.ccl.net (8.8.3/8.8.6/OSC/CCL 1.0) with SMTP id SAA26410 Tue, 11 Aug 1998 18:36:48 -0400 (EDT) Received: (qmail 17790 invoked by uid 0); 11 Aug 1998 22:36:20 -0000 Message-ID: <19980811223620.17789.qmail@hotmail.com> Received: from 128.102.199.140 by www.hotmail.com with HTTP; Tue, 11 Aug 1998 15:36:19 PDT X-Originating-IP: [128.102.199.140] From: "Artiben Taylor" To: chemistry@www.ccl.net Subject: Optimization problem Date: Tue, 11 Aug 1998 15:36:19 PDT I am trying to optimize a structure with opt=(tight,maxcyc=100). But the geometry is not converging. After 4 converging point it comes back to the original point. Item Value Threshold Converged? Maximum Force .000018 .000015 NO RMS Force .000008 .000010 YES Maximum Displacement .009113 .000060 NO RMS Displacement .003305 .000040 NO Kind of trapped in a loop. I tried to reoptimize the geometry by changing little. But it doesnt help. In another probelm, I am getting YES flags for the optimization but in the frequency calculation I am getting the RMS as NO. I would appreciate to receive your comments. Thanks. Artiben. ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com From chemistry-request@www.ccl.net Tue Aug 11 21:45:46 1998 Received: from sable.nus.edu.sg (sable.nus.edu.sg [137.132.1.21]) by www.ccl.net (8.8.3/8.8.6/OSC/CCL 1.0) with ESMTP id VAA27205 Tue, 11 Aug 1998 21:45:45 -0400 (EDT) Received: from leonis.nus.edu.sg (chmcws@leonis.nus.edu.sg [137.132.1.18]) by sable.nus.edu.sg (8.8.8/8.6.9) with ESMTP id JAA25175 for ; Wed, 12 Aug 1998 09:45:45 +0800 (SST) Received: (from chmcws@localhost) by leonis.nus.edu.sg (8.8.8/8.6.9/CNS-3.5) id JAA05786; Wed, 12 Aug 1998 09:45:43 +0800 (SST) Message-Id: <199808120145.JAA05786@leonis.nus.edu.sg> Subject: CCL:Valence DOS calculations To: chemistry@www.ccl.net Date: Wed, 12 Aug 1998 09:45:43 +0800 (SST) From: "Chin Wee Shong" Cc: chmcws@leonis.nus.edu.sg (W S Chin) Dear CCLers, I am looking at ways/programmes to calculate the density of states for some simple organic molecules in order to correlate that to their valence electronic structures. Can someone please give your kind advice or pointers ? Regards, Lim S L e-mail:scip4160 @ leonis.nus.edu.sg