From chemistry-request@server.ccl.net Tue Apr 27 03:26:56 1999 Received: from alpha.luc.ac.be (alpha.luc.ac.be [193.190.2.30]) by server.ccl.net (8.8.7/8.8.7) with ESMTP id DAA01694 for ; Tue, 27 Apr 1999 03:26:53 -0400 Received: from sbg-ts (sbg-ts.luc.ac.be [193.190.1.15]) by alpha.luc.ac.be (8.9.3/8.9.3) with SMTP id JAA04828 for ; Tue, 27 Apr 1999 09:25:11 +0200 (MET DST) Date: Tue, 27 Apr 1999 09:25:11 +0200 (MET DST) Message-Id: <199904270725.JAA04828@alpha.luc.ac.be> X-Sender: skwasnie@mail.luc.ac.be X-Mailer: Windows Eudora Pro Version 2.1.2 Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" To: chemistry@ccl.net From: sergiusz kwasniewski Subject: Re: CCL:excitation energies Hi, for the semi-empirical techniques, I've been using the whole space (Energy criterium is 1000 eV), while for the ab initio methods the basis set is 6-311G(d,p) within the FC approximation... But I'm concerned about the low energy part of the spectrum, and then the criterium inside the semi-empirical techniques doesn't change much the appearence of the spectrum. Did anyone encounter these inconsistencies? (More information about this, was inside my last mail) Thanks in advance Sergiusz At 11:57 AM 4/26/99 -0300, Sergio Emanuel Galembeck wrote: >Dear Sergiusz, > > What basis are you using? I don't have experience >on RHF/CIS, but the results depends on basis sets >and on the choice of active space. > > Best regards, > > Sergio > >PS: Please, sumarize the answers. > >============================================== >Sergio Emanuel Galembeck >e-mail: segalemb@usp.br >=============================================== _________________________________________________ Sergiusz Kwasniewski LUC SBG/TS Universitaire Campus Gebouw D 3590 Diepenbeek BELGIUM tel(direct): 011/268315 fax : 011/268301 email : sergiusz.kwasniewski@luc.ac.be _________________________________________________ From chemistry-request@server.ccl.net Tue Apr 27 10:07:22 1999 Received: from tigris.klte.hu (tigris.klte.hu [193.6.138.33]) by server.ccl.net (8.8.7/8.8.7) with SMTP id KAA05084 for ; Tue, 27 Apr 1999 10:07:15 -0400 Message-Id: <199904271407.KAA05084@server.ccl.net> Received: from anti02 (anti02.chem.klte.hu) by tigris.klte.hu (MX V4.1 VAX) with SMTP; Tue, 27 Apr 1999 16:03:13 +0100 Comments: Authenticated sender is From: "Tamas Gunda" To: chemistry@ccl.net Date: Tue, 27 Apr 1999 16:04:12 +1 MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Subject: CD spectra Priority: normal X-mailer: Pegasus Mail for Windows (v2.42a) Dear Netters, On probing into the details of calculating CD spectra, I came across a program (package), called BDZDO/MCDSPD, which makes the starting CNDO/S-CI calculations and then the calculation of the rotational strengths etc, and the final spectra. Could anybody tell me about the origin/availability of this application (or a corresponding similar one)? best regards Dr Tamas E. Gunda ************************************************************************ Dr Tamas E. Gunda phone: (+36-52) 316666-2479 Research Group of Antibiotics fax : (+36-52) 310936 L. Kossuth University e-mail: tamasgunda@tigris.klte.hu POBox 36 http://dragon.klte.hu/~gundat H-4010 Debrecen Hungary ************************************************************************ From chemistry-request@server.ccl.net Mon Apr 26 19:58:13 1999 Received: from www.ccl.net (www.ccl.net [192.148.249.5]) by server.ccl.net (8.8.7/8.8.7) with ESMTP id TAA08321 for ; Mon, 26 Apr 1999 19:58:11 -0400 Received: from gate-sl1.mdli.com (ns2.mdli.com [208.200.221.3]) by www.ccl.net (8.8.3/8.8.6/OSC/CCL 1.0) with ESMTP id TAA08829 Mon, 26 Apr 1999 19:53:36 -0400 (EDT) Received: (from smap@localhost) by gate-sl1.mdli.com (8.8.8/8.8.8) id QAA18720; Mon, 26 Apr 1999 16:43:14 -0700 (PDT) Received: from puffin.mdli.com(191.254.19.10) by gate-sl1.mdli.com via smap (V2.1) id xma018718; Mon, 26 Apr 99 16:43:13 -0700 Received: from shepherd.mdli.com by puffin.mdli.com (8.8.5/BCH1.0) id QAA01293; Mon, 26 Apr 1999 16:53:22 -0700 (PDT) Received: by shepherd.mdli.com with Internet Mail Service (5.5.2232.9) id ; Mon, 26 Apr 1999 16:55:36 -0700 Message-ID: <8E13FBBA26A9DA119ED400A0C9AB2CE501397656@shepherd.mdli.com> From: Guenter Grethe To: CHMINF-L , Computational Chemistry List , Derwent List , Diversity LIst , Medicinal Chemistry List Cc: "'Guenter Grethe'" , Jacques Weber , Janet Ash , John Blackmore , Rainer Moll , Vincent van Geerestein , Willie Brukx Subject: 5th International Conference on Chemical Structures - Final Program Date: Mon, 26 Apr 1999 16:55:26 -0700 I APOLOGIZE FOR DUPLICATE POSTINGS. The Fifth International Conference on Chemical Structures is only a few weeks away (June 6 - 10). The Organizing Committee has put together an exciting program which is attached to this message. Those of you who participated in one of the earlier conferences know that this is one of the important venues for Chemical Information practitioners. In case you make a last-minute decision to participate please register as soon as possible as we are running out of rooms at the center. You can find information about registration on our web site at http://ChemWeb.com/conference/5iccs/5iccs.html. From chemistry-request@server.ccl.net Mon Apr 26 20:05:25 1999 Received: from serval.noc.ucla.edu (serval.noc.ucla.edu [169.232.10.12]) by server.ccl.net (8.8.7/8.8.7) with ESMTP id UAA08508 for ; Mon, 26 Apr 1999 20:05:25 -0400 Received: from indium (Indium.seas.ucla.edu [128.97.83.8]) by serval.noc.ucla.edu (8.9.1a/8.9.1) with SMTP id RAA23749 for ; Mon, 26 Apr 1999 17:00:50 -0700 (PDT) Message-ID: <000b01be9040$6a3334c0$08536180@indium.seas.ucla.edu> From: "Qiang" To: Subject: G98 Frequency Date: Mon, 26 Apr 1999 16:56:34 -0700 Hi, I am trying to calculate the frquencies of a cluster In7P8H21 with G98W. = The structure was optimized with DFT (PW91PW91) with 6-31G** for P and = H; ECP(LANL2DZ) for In. When it came to frequency calculation, I got an = error message:=20 **** Warning!! The samllest alpha delta epsilon is 0.80370032D-01 The link then died. Could any one (especially the experts from Gaussian, Inc) give me some = suggestion about the problem? Thank you very much Qiang From chemistry-request@server.ccl.net Tue Apr 27 01:09:12 1999 Received: from postoffice.igalaxy.net ([207.126.82.14]) by server.ccl.net (8.8.7/8.8.7) with ESMTP id BAA00635 for ; Tue, 27 Apr 1999 01:09:11 -0400 From: kaynjay@igalaxy.net Received: from kaynjay [207.126.85.219] by postoffice.igalaxy.net (SMTPD32-5.01) id A7599DCF023C; Mon, 26 Apr 1999 22:12:57 PDT Date: Mon, 26 Apr 1999 21:20:05 -0700 To: CCL Subject: Rolling H charges into their heavy atoms? Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===_372545BD_==" X-Mailer: MR/2 Internet Cruiser Edition for OS/2 v1.52 b52 Message-Id: <199904262212.SM00238@kaynjay> This is a MIME encapsulated message. --===_372545BD_== Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Hello people, I wanted some opinions from those well versed in the field about a practice I've seen mentioned in some docking studies with proteins (an area in which I'm interested). Most PDB files have no H's mapped. Since the ESP is important in those studies, having some good estimate for the partial nuclear charges is naturally important. It appears that one can either add the H's onto the existing structure or take a well-calculated amino acid structure (using an ab initio program) and additively "roll" the nonpolar H charges into their respective heavy nuclei. In this case, those which might H-bond seem to be treated separately (added to the structure), which makes sense to me. First, is this a reasonable 1st-level understanding of the approaches to this? Or have I misunderstood things? The second approach (rolling charges into the heavy atoms) would certainly appear to be the easiest to adopt. Is there good reason Not to do either approach? In both I can see an issue of accuracy for a number of obvious reasons from the QM perspective, but wonder about the validity of this concern on the broad scale over which these protein interactions occur. Any references would also be appreciated. My apologies if this seems trivial or mundane ... I'm quite new to all of this, and am learning it near the back of a dark cave ... :) Thanks very much! Kenward Vaughan Professor of Chemistry Bakersfield College Bakersfield, CA 661-395-4243 kvaughan@bc.cc.ca.us (work) -- ----------------------------------------------------------- kaynjay@igalaxy.net ----------------------------------------------------------- --===_372545BD_==-- From chemistry-request@server.ccl.net Tue Apr 27 01:32:39 1999 Received: from www.ccl.net (www.ccl.net [192.148.249.5]) by server.ccl.net (8.8.7/8.8.7) with ESMTP id BAA00865 for ; Tue, 27 Apr 1999 01:32:39 -0400 Received: from office.un.md (root@office.un.md [212.0.211.34]) by www.ccl.net (8.8.3/8.8.6/OSC/CCL 1.0) with SMTP id BAA09103 Tue, 27 Apr 1999 01:29:36 -0400 (EDT) Received: from un.md (ppp235.mldnet.com [212.56.193.235]) by office.un.md (8.6.13/8.6.12xla) with SMTP id IAA19994; Tue, 27 Apr 1999 08:28:53 +0300 Date: Tue, 27 Apr 1999 08:30:32 +0300 From: Mike Peleah X-Mailer: The Bat! (v1.15) S/N B6042885 Reply-To: Mike Peleah X-Priority: 3 (Normal) Message-ID: <10354.990427@mail.ru> To: gamess-users@Glue.umd.edu Subject: PC GAMESS and UV-Vis spectra Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit +======================---------------- --- -- - - - - . | Hello everybody, : . Could anybody provide me examples of input files for calculation UV-Vis spectra using (PC) GAMESS? Also I would be great if somebody point me where could I read more about calculation UV-Vis spectra using GAMESS (Internet on-line and ftp resources are preferable). Best regards, Mike mailto:MikePeleah@mail.ru . ... Bring the power of XT to your Pentium-II: use Windows NT. : | . - - - - -- --- ----------------======================+ From chemistry-request@server.ccl.net Tue Apr 27 04:21:14 1999 Received: from sivka.carrier.kiev.ua (root@sivka.carrier.kiev.ua [193.193.193.101]) by server.ccl.net (8.8.7/8.8.7) with ESMTP id EAA02342 for ; Tue, 27 Apr 1999 04:21:12 -0400 Received: from kozlik.carrier.kiev.ua (kozlik.carrier.kiev.ua [193.193.193.111]) by sivka.carrier.kiev.ua (8.Who.Cares/8.Who.Cares) with ESMTP id LAA03899 for ; Tue, 27 Apr 1999 11:18:24 +0300 (EEST) (envelope-from vkhavr@compchem.kiev.ua) Received: (from uucp@localhost) by kozlik.carrier.kiev.ua (8.Who.Cares/8.Who.Cares) with UUCP id LAA11333 for chemistry@server.ccl.net; Tue, 27 Apr 1999 11:16:28 +0300 (EEST) (envelope-from vkhavr@compchem.kiev.ua) Received: from compchua.UUCP (rmail pid=11332) by kozlik.carrier.kiev.ua with UUCP; Tue, 27 Apr 1999 08:16:28 GMT Received: from compchem.kiev.ua (boss.compchem.kiev.ua [10.0.2.3]) by netmaster.compchem.kiev.ua (8.9.1/8.9.1) with ESMTP id KAA16279 for ; Tue, 27 Apr 1999 10:04:26 +0200 Message-ID: <37257092.F8143ED9@compchem.kiev.ua> Date: Tue, 27 Apr 1999 11:08:51 +0300 From: Khavryutchenko Vladimir D Organization: CompChem X-Mailer: Mozilla 4.06 [en] (WinNT; I) MIME-Version: 1.0 To: chemistry@server.ccl.net Subject: ZINDO source code Content-Type: text/plain; charset=koi8-r Content-Transfer-Encoding: 7bit Dear CCLers, Does anybody know (or have) ZINDO program source code? I would like to compare this method results with our NDDO program under development. Closed programs like HyperChem may not show some important details of calculation. Regards V.Khavryutchenko CompChem group Kiev Ukraine From chemistry-request@server.ccl.net Tue Apr 27 04:22:39 1999 Received: from wiggum.ruc.dk (wiggum.ruc.dk [130.225.220.118]) by server.ccl.net (8.8.7/8.8.7) with ESMTP id EAA02367 for ; Tue, 27 Apr 1999 04:22:38 -0400 Received: from virgil.ruc.dk (virgil.ruc.dk [130.225.220.110]) by wiggum.ruc.dk (2.1.1/8.9.1/Execmail 2.1) with ESMTP id KAA13773; Tue, 27 Apr 1999 10:19:33 +0200 (MET DST) Received: from VIRGIL/SpoolDir by virgil.ruc.dk (Mercury 1.40); 27 Apr 99 10:21:11 +0100 Received: from SpoolDir by VIRGIL (Mercury 1.40); 27 Apr 99 10:21:07 +0100 From: "Jens Spanget-Larsen" Organization: Roskilde Universitetscenter To: sergiusz kwasniewski Date: Tue, 27 Apr 1999 10:20:45 +0100 Subject: Re: CCL:excitation energies CC: chemistry@ccl.net Priority: normal X-mailer: Pegasus Mail for Windows (v2.23) Message-ID: <162D1281FBD@virgil.ruc.dk> Mon, 26 Apr 1999: sergiusz.kwasniewski@luc.ac.be> CCL:excitation energies > Does anyone know something about the difference between the excitation > energies calculated by RHF CIS and semi-empirical techniques like ZINDO/S > CIS on organic structures? I've done some calculations on aromatic > structures, but the spectra are not comparable at all! Is there a reason for > that behaviour? > BTW: the semi-empirical calculations are in agreement with experiment. Dear Sergiusz, HF CIS calculations are generally in error because of neglect of electronic correlation effects. These effects tend to stabilize excited states more than the ground state, and the result is that HF CIS frequently predicts excitation energies that are much too large. Semiempirical procedures like ZINDO/S are especially parameterized to account for the effects of electron correlation (in particular, by empirical adjustment of the parameters used to estimate electron repulsion terms), and these procedures thus predict transition energies of the right order of magnitude, at least for the class of compunds and types of transition for which they were parameterized. By the way, have you tried to apply Time Dependent Density Functional Theory (TD DFT) as implemented in Gaussian 98? For example, TD B3LYP does a great job for electronic transitions. Yours, Jens >--< =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= JENS SPANGET-LARSEN Phone: +45 4674 2000 (RUC) Department of Chemistry +45 4674 2710 (direct) Roskilde University (RUC) Fax: +45 4674 3011 P.O.Box 260 E-Mail: JSL@virgil.ruc.dk DK-4000 Roskilde, Denmark http://www.rub.ruc.dk/dis/chem/psos/ =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= From chemistry-request@server.ccl.net Tue Apr 27 09:43:37 1999 Received: from www.ccl.net (www.ccl.net [192.148.249.5]) by server.ccl.net (8.8.7/8.8.7) with ESMTP id JAA04882 for ; Tue, 27 Apr 1999 09:43:37 -0400 Received: from galaad.citi2.fr (galaad.citi2.fr [192.70.98.7]) by www.ccl.net (8.8.3/8.8.6/OSC/CCL 1.0) with ESMTP id JAA10164 Tue, 27 Apr 1999 09:40:27 -0400 (EDT) Received: from bisance.citi2.fr (bisance.citi2.fr [192.70.98.30]) by galaad.citi2.fr (8.8.8/jtpda-5.3) with ESMTP id PAA15394 for ; Tue, 27 Apr 1999 15:40:26 +0200 (MET DST) Received: from (kozelka@localhost) by bisance.citi2.fr (8.8.8/jtpda-5.3) id PAA06275 for chemistry@www.ccl.net; Tue, 27 Apr 1999 15:40:25 +0200 (MET DST) From: kozelka@citi2.fr (JirKa Kozelka) Message-Id: <199904271340.PAA06275@bisance.citi2.fr> Subject: Summary:HOMO-LUMO gap in Pt(II) To: chemistry@www.ccl.net Date: Tue, 27 Apr 1999 15:40:24 +0200 (MET DST) X-Mailer: ELM [version 2.4 PL25] MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Some days ago, I sent to CCL a question concerning the HOMO-LUMO gap in Pt(II) complexes. I should perhaps have specified that I was not primarily interested in excitation energies (at least for the moment), but wanted to use the HOMO-LUMO-gap as a check whether the calculations were reasonable. I have obtained a series of quick responses which are given below. I would like to express my thanks to all contributors for their interesting comments. ********************** Initial Question: Dear CCL-members, I have carried out a number of SCF calculations on Pt(II) complexes with chloride, amine, and phosphine ligands, using Gaussian 94 and 98, with different basis sets, and find consistently HOMO-LUMO gaps of 0.3-0.4 Hartrees, i.e., 65000-90000 cm-1. This is roughly 3 times the excitation energies of spin-allowed d-d bands seen in solutions of these species. The difference seems too big to me to be explained by electron relaxation. I would very much appreciate comments and/or explications on/of this apparent discrepancy. We have seen that the bond lengths and dipole moment coming from HF calculations are quite wrong for these compounds, and one has to apply correlated methods to get these quantities right. But can it be that the difference in energies of the HF HOMO/LUMO one-electron orbitals is so far from the excitation energy? I shall summarize the answers. Thanks, Jirka Kozelka ************************** Answers: *************************** Hello, Jirka. Recently we have been involved in the theoretical calculation of band gaps of ionic crystals. They are certainly a type of materials different from those you are considering, but perhaps the main findings could be relevant to you. We have found that inclusion of electron relaxation (by means of a DeltaSCF procedure, that is separate calculations on the ground and excited states an difference of total energies) changes the magnitude of the band gap by more than 3 eV in some cases (aprox. 0.1 hartrees). The effect of correlation on the band gap was also accusated (2-3 eV), and crucial in order to achieve a good agreement with experimental results. If you are interested, you can download copies of our works from http://xxx.lanl.gov/abs/cond-mat/9809176/ http://xxx.lanl.gov/abs/cond-mat/9901145/ best wishes, Andres Aguado. **************************** I would be very much surprised if you (for Pt compounds) would obtain better results. Generally, the IP's (Excitation energies and EA's) in heavy metal compounds are very much influenced by relativistic effects. You probably used RECP's which include the mass-velocity and Darwin terms (being derived on DHF atomic calculations) and thus you could argue that the relativistic effects are partially included. However, the correlation energy in Heavy-Metal systems is by far more important as it is for "regular" organic systems. Especially, the correlation contribution to the relativistic (de)stabilization is usually responsible for more than 50% of the energy (IP, E(ex), BDE, etc.). If you are interested in qualitative numbers and if you are willing to accept errors of ~0.5 eV you may try some of the DFT methods, which are in connection with a proper RECP quite "cheap" and were proven to offer reasonable results. The Kohn-Sham orbitals will give you an estimate (not theoretically justified) for the numbers you are looking for. On the other hand you may suffer from the inappropriate description of the "exchange-correlation" which quite often leads to larger errors (wrong ground states of the atoms) and for sure you miss the important spin-orbit effect. Best regards Jan Hrusak **************************** If one examines excited states using CI theory one sees that the diagonal of the CI matrix is E(lumo)-E(homo) - [exchange and coulombic terms expressed in an Molecular Orbital basis]... A decent theory book would probably tell you exactly what the correction terms are. John McKelvey ************************* Hi ! I just read your message on the CCL-list. Unfortunately I am no expert in HOMO-LUMO gaps, but I would be curious if you also tried to use completely uncontracted basis functions for you calculations too ? If your compounds are closed shell systems, we could try to recompute it with my own HF-code for comparitive purposes only. Best greetings Siegfried *************************** Jirka, With any SCF method, the LUMO energy of a gas phase molecule will always be exactly 0.0 hartree at the basis set limit. Thus, in effect, you can obtain the LUMO energy that you desire by "wisely" choosing your basis set. Only the total energies (kinetic, e-N, N-N, e-e) have physical significance. Preston MacDougall *************************** Dear Jirka, the HOMO/LUMO gap can not be directly correlated with the excitation energies! In case of close shell molecule, the excitation energy E* from HOMO to LUMO is expressed by E*= E(LUMO) - E(HOMO) - J(HOMO,LUMO) + 2 K(HOMO,LUMO) where J and K are coulomb and exchange integrals and E's are eigenvalues. (no CI is also assumed) Since for d orbitals J(HOMO,LUMO) is quite large (~10 eV), the excitation energies are significantly lower than HOMO/LUMO gap. Serge Gorelsky ****************************** Hi Jirka, as a method I would recommend LDA (SVWN) rather than HF or MP2. LDA (no gradient corrections) gives much better geometries. Concerning the HOMO-LUMO gap, I assume you will get very good and sound comments to it - much better than I can give. But I recall that HOMO-LUMO gap does correspond to transitions and the HOMO-LUMO gap is by a factor of about 2 larger. If you do not get other answers I will look up the reference for you. Generally I am very interested in what kind of Pt complexes you are interested in and what properties you investigate. Our homepage is just under constructions, but do give you a feel of what we doing you might want to have a look at our test-version. http://nitrogen.cem.uct.ac.za/achim/indexpgm.htm (no WWW !!) Best regards Achim *************************** I'm not sure if this helps much, but HF theory tends to yeild a HOMO-LUMO which is too big. LDA on the other hand yeilds a HOMO-LUMO which is too small. And B3LYP tends to yeild a HOMO-LUMO which is just right. I'd give it a try. All the best, Matt Matt Challacombe ************************* Jirka: Many years ago I did all the excitation energies for the chloride systems by appropriatly populating the d orbitals and the excitation energies are in reasonable accord with the experiments. Mo Krauss ********************* Dear Jirka, modeling a complex in solution by SCF calculations in the gas phase contains two errors: You neglect correlation and solvent effects. Normally reaction energies are more sensitive to correlation than the geometry. I would not be surprised if this holds for HOMO-LUMO gaps too. By the way, DFT methods include correlation effects and are only slightly more expensive than HF calculations. The HOMO -> LUMO transition is accompanied by a change of the charge distribution. Since the solvent can be polarized by the solute, your ground and excited state energies are lowered (by different amounts) in the presence of a solvent. There are two methods for inclusion of solvents, explicitly including the solvent molecules into the calculation (expensive!) and using a polarizable continuum as a model for the solvent (cheaper). Stefan ______________________________________________________________________ Dr. Stefan Fau ****************************** Dear Jirka The HOMO-LUMO gap calculated with the HF method, is almost allways far from the observed excitation energy.. There are several other methods which are suitable for this kind of calculations e.g CIS (C.I. sinnglets calculations). Even semiempirical methods (suitably parametrized) usually give HOMO-LUMO gaps which are closer to the observed ones. C. Garoufalis University of Patras, Dept of Physics **************** Dear Jirka, Have you compared the experimental excitation energies to those came from CIS calculations? They should be much more precise since CIS is developed for this aim, and in fact, this is the cheepest ab initio tool to perform such a calculation. Using Gaussian, you may even take the solvent effects into account. I would suggest to try this. Also, in the former days of spectroscopy, semiempirical methods were used for predicting electron excitation and ionisation energies. If everything else fails, i would -at least- try some of them. Most of them is parametrized on experimental data (IPs, etc.) Many programs that are dealing with semiempirical calculations allows you to carry out CIS calculations on semiempirical SCF, as well. For very large systems -in my opinion- this is the only way. Hope this helps. Best wishes, Tamas Karpati Technical University of Budapest, Hungary ******************** I sent a reply to Serge: Dear Serge, >From Jorgensen's book "Absorption Spectra and Chemical Bonding in Complexes", I once calculated the change in interelectron repulsion for the d-d transitions in square-planar complexes. For the spin-allowed dz2 to dx2-y2 transition, for instance, I obtained E* = E(LUMO) - E(HOMO) - 4B -C. Taking for the Racah parameter B Jorgensen's value of 600 cm-1 and C = 4B, I get a correction term 4B + C = 4800 cm-1 which is somewhat more than 0.5 eV. Even if I take larger estimates for B, like , e.g., 822 cm-1 obtained by Vanquickenborne & Ceulemans (Inorg.Chem.,20, 796,1981), I do not obtain more than 1 eV. That is why I neglected the interelectron repulsion while posing my question. Your estimate is perhaps valid for some metal ions with more contracted orbitals? I would like to know how you have obtained it. Thank you anyway for responding so quickly. Greetings, Jirka ****************** ...and got the following comment back: well, this expression is not valid if E(LUMO) and E(HOMO) are "true" HF eigenvalues. Racah papameters are small because they characterize "nonspherical" effects in interelectronic repulsion. J(d,d) integral is much bigger than B and C and in 8-15 eV for practically all transition metals. Serge Gorelsky ******************* From chemistry-request@server.ccl.net Tue Apr 27 09:56:21 1999 Received: from www.ccl.net (www.ccl.net [192.148.249.5]) by server.ccl.net (8.8.7/8.8.7) with ESMTP id JAA05001 for ; Tue, 27 Apr 1999 09:56:20 -0400 Received: from hotmail.com (wya-oe7.hotmail.com [207.82.253.72]) by www.ccl.net (8.8.3/8.8.6/OSC/CCL 1.0) with SMTP id JAA10205 Tue, 27 Apr 1999 09:53:02 -0400 (EDT) Received: (qmail 83129 invoked by uid 0); 27 Apr 1999 13:47:11 -0000 Message-ID: <19990427134711.83128.qmail@hotmail.com> Received: from 207.176.233.24 by wy1lg.hotmail.com with HTTP; Tue, 27 Apr 1999 06:47:10 PDT X-Originating-IP: [207.176.233.24] From: "Mike McBrien" To: msj@fskru5.hre.hydro.com, chemistry@www.ccl.net Subject: Re: CCL:Estimation of vapour pressure of organic liquids and solids Date: Tue, 27 Apr 1999 06:47:10 PDT Mime-Version: 1.0 Content-type: text/plain Hello, Merethe. Advanced Chemistry Development makes a BP/Vapour Pressure/Flash Point Calculation product. It bases the calculation of these values on: - an internal database of about 10000 compounds - estimated Molar Volume of the compound - a proprietary algorithm that estimates the value of BP/VP/Flash Point/ Enthalpy of Vapourisation. There is more information at: http://www.acdlabs.com/products/bp/ Best regards, Mike. >From: "Merethe Sjovoll" >To: chemistry@www.ccl.net >Subject: CCL:Estimation of vapour pressure of organic liquids and solids >Date: Thu, 22 Apr 1999 10:14:29 -0600 > >Hi everybody, > >is there a way of estimating in a crude way the vapour pressure of organic >liquids and solids? I have a whole bunch of molecules and I don't need absolute >values, just look for tendencies. So I imagine some calculation formula which >perhaps contains temperature, possibly boiling point and melting point, or >perhaps dipole moment, molecular weight etc. (easily accessible quanities). > >Is this wishful thinking? > >Best regards > >Merethe Sjovoll > >-- > >******************************************************** >Merethe Sjovoll, Ph.D. * * >Senior Research Scientist * * >Norsk Hydro a.s Research Center * * > * * >P.O.Box 2560 * HYDRO * >N-3907 Porsgrunn, * RESEARCH * >Norway * * > * ((( * >email: Merethe.Sjovoll@hre.hydro.com * (=====) * >Phone:+47 35 56 48 97 * * >Fax :+47 35 56 27 22 * * >******************************************************** >-= This is automatically added to each message by mailing script =- >CHEMISTRY@ccl.net -- To Everybody | CHEMISTRY-REQUEST@ccl.net -- To Admins >MAILSERV@ccl.net -- HELP CHEMISTRY or HELP SEARCH >CHEMISTRY-SEARCH@ccl.net -- archive search | Gopher: gopher.ccl.net 70 >Ftp: ftp.ccl.net | WWW: http://www.ccl.net/chemistry/ | Jan: jkl@ccl.net > > > > > ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com From chemistry-request@server.ccl.net Tue Apr 27 13:05:57 1999 Received: from ludwig.psc.edu (ludwig.psc.edu [128.182.62.192]) by server.ccl.net (8.8.7/8.8.7) with ESMTP id NAA07888 for ; Tue, 27 Apr 1999 13:05:57 -0400 Received: (from nystrom@localhost) by ludwig.psc.edu (8.8.5/8.8.2) id NAA29480 for chemistry@ccl.net; Tue, 27 Apr 1999 13:02:50 -0400 From: "N.A. Nystrom" Message-Id: <199904271702.NAA29480@ludwig.psc.edu> Subject: Workshop: DEVELOPING AND USING PC CLUSTERS AS A BIOMEDICAL RESEARCH TOOL To: chemistry@ccl.net Date: Tue, 27 Apr 1999 13:02:48 -0400 (EDT) X-Mailer: ELM [version 2.4 PL17] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit DEVELOPING AND USING PC CLUSTERS AS A BIOMEDICAL RESEARCH TOOL Workshop Dates: June 17-19, 1999. Application deadline: May 20, 1999 This workshop is designed to assist biomedical researchers who are interested in establishing a PC cluster for use by their laboratory. The workshop will address software and hardware topics encountered in the process of building, operating and managing a PC cluster. In addition, software development issues will also be described. Topics of discussion will include: "What do you need to consider when creating an operating environment?" "How to select System Software?" "How to Administer the Cluster?" "What applications are appropriate?" and "How to get the best performance for your money?" Full details, including on-line applications and financial support, may be found on the PSC Web site: http://www.psc.edu/biomed/workshops/workshops.html The Pittsburgh Supercomputing Center's Biomedical Initiative is an NIH Supported Resource Center.