From maiden@RedBrick.DCU.IE Fri May 9 05:41:57 1997 Received: from tolka.dcu.ie for maiden@RedBrick.DCU.IE by www.ccl.net (8.8.3/950822.1) id EAA16253; Fri, 9 May 1997 04:48:12 -0400 (EDT) Received: from Nurse.RedBrick.DCU.IE by tolka.dcu.ie; (5.65v3.2/1.1.8.2/14Feb96-0535PM) id AA26793; Fri, 9 May 1997 09:46:09 +0100 Received: from localhost (maiden@localhost) by RedBrick.DCU.IE (SomeMTA) with SMTP id JAA00686 for ; Fri, 9 May 1997 09:47:38 +0100 (BST) Organisation: DCU Networking Society X-Disclaimer: The DCUNS is not responsible for the content of this message X-Award: Most Improved Society 1996-7 Date: Fri, 9 May 1997 09:47:38 +0100 (BST) From: Michael Nolan To: chemistry@www.ccl.net Subject: Re: mn and cr complexes (Summary: part 1) Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Hi CCL!! thanks again to all those who replied to my pathetic problems with the aforementioned complexes. I am posting the summary in two parts, because I got a lot of answers. The first is this extremely helpful reply from Prof. Guest. The answer to most of problems was so simple: (i) increase the number of cycles allowed! (ii) changing the LEVEL keyword in GAMESS-UK helped enormously. I also found that starting with a short M-C bond length (1.75 A) helped The replies also opened my eyes to how tough TM complexes can be. I knew that there could be problems because of the d-orbitals, but now I know better. It seems also that a correlated method should be used. Our HF results are giving a different ordering of the HOMO-1, HOMO, LUMO and LUMO+1 orbitals to that from Hoffmann et al (JACS 1976, 98, 7546 i think) and Byers and Hall's work (Organometallics 1987). Anyway, thanks to everyone again. Michael Der Kobold hat gesprochen ****************************************************************************** Michael Nolan (nearly BSc.) Dublin City University (quantum chem.) 41 Woodview Chemistry + German Year 4 Lucan Co. Dublin Ireland / Republic of Ireland / ROI / Eire Email: Maiden@redbrick.dcu.ie ****************************************************************************** Date: Wed, 30 Apr 1997 22:32:14 +0100 From: "M.F.Guest" To: Maiden@RedBrick.DCU.IE Cc: gamess_uk_support@dl.ac.uk, wab@dl.ac.uk Subject: Re: mn complexes Dear Michael, > I am trying to run ab-initio calculations on Mn(CO)3 and Cr(CO)3, using > GAMESS-UK. First, let me say that I am sorry you are having so many problems trying to get these SCF transition metal complexes sorted out. If you email me the associated input data sets and key sections of the O/P files, I will run these for you and help resolve the source of the problems you are encountering. I've run well over 150 TM complexes using the code, and am very confident that I can resolve the matters that are causing grief. First, a couple of general guidelines. Convergence problems of the type you have encountered ("excessive iterations", oscillating energies etc) can arise for a number of different reasons, and with the information to hand its difficult to provide a definitive answer to what is happening, but the following may help: 1. oscillations in the energy can often be resolved by increasing the value of the "level shifter" used in the calculation over and above the defaults. Thus, assuming you are on the correct initial configuration (see below for more on that), then presenting the data sequence level 5 20 2 maxcyc 100 will often help. You need to drive the calculation into the regime where the DIIS convergence scheme is called into play, from which point hopefully progress will be a lot better. 2. Bear in mind that running with "RUNTYPE OPXYZ" will require a stricter convergence of the SCF calculation (10**-7 rather than 10**-5 in the "tester"), and you may just be running out of cycles (the default 50). Without seeing the O/P it is difficult to be more precise on this, although if the energy is oscillating that is clearly not the problem. 3. There is no guarantee that the initial SCF configuration is "correct", particularly for TM complexes where their may be a multitude of low lying excited states, and in cases of high symmetry (as in your examples). In the absence of any better starting point, you should use the default "guess" option (vectors atoms). If you have successfully converged a related compound with similar geometry or basis, then you should use these vectors as a source of input to start the SCF. Thus if you have the Mn(CO)3 vectors on say the dumpfile mnco3.ed3, then use these to start the Cr(CO)3 calculation, using the directive vectors getq ed4 1 1 where I'm assuming that mnco3.ed3 is assigned to the calculation using the LFN ED4 (perhaps via the setenv environment setting setenv ed4 mnco3.ed3 and that the converged Mn(CO)3 vectors reside in section 1. This will definitely help. 4. Note that if you inadvertently "split" the degeneracy of the starting SCF orbitals then you will not recover (you can check this by looking at the final set of eigen values). The energy may well crash below that expected when for example degenerate e orbitals are symmetry broken, and you must try and avoid that by ensuring the starting mos exhibit the correct degeneracies. Looking at the specific points you raised: > 1) RHF/3-21G (3-21G on all atoms) for Mn(CO)3 this is successful, for > Cr(CO)3 I get excessive number of iterations and an oscillation of the > energy. Use the converged Mn(CO)3 vectors as input to the Cr(CO)3 calculation as noted above, using "level 3.0 25 2.0" > 2) RHF, 6-21G on C and O, 3-21G on Mn. for Mn(CO)3, this is successful > 3) RHF with minimal basis ECP on all atoms for Mn(CO)3 and Cr(CO)3. > This gives a ludicrously low energy (about -70a.u.), oscillations in the > energy and excessive number of iterations > I have inputted a z-matrix, cartesian coordinates from X-ray diffraction > studies (using both OPTXYZ keyword and the cartesian coordinates to > z-matrix conversion) and the idealised geometry above and I get the same > result with them all - excessive number of iterations etc.. Again, a no. of reasons why this could happen, with a splitting in degeneracy of the input MOs a likely candidate. You have to damp the oscillations with "level" > 4) RHF as above, but ECP-double zeta (ECPDZ) on all atoms same result > 5) RHF, min. basis ECP and ECPDZ on Mn, 3-21G and 6-31G on C and O > see number 4. > I assume the fact that Mn(CO)3 is positively charged has nothing to do > with it (it is a closed shell). > I know that 3-21G and 6-31G are not good for transition metals, yet I got > reasonable results using these (MOs and charge distribution). > Does anyone have any ideas for how I can use ECPs (we are limited to > about 1.2GB) or anything else to get these calculations to run (we do > not yet have DFT). As I said at the outset, I've run a lot of TM ECP calculations without experiencing the sort of problems you have encountered. You could try just siting the ECP on the TM to start with; are these calculations using the Hay and Wadt ECP's, or those due to Stevens et al. I've found the latter a lot better, and would suggest you try these. > As an aside, I keep getting an error message when > converting from cartesian coordinates to z-matrix. Has anyone else had > this? I seem to remember seeing an example like this posted to the GAMESS-UK support list. If you have not received any feedback let me be the first to apologise; Allan Beveridge, who was appointed to deal with this type of query left his position a month or so ago, and we are a bit thin on the ground in trying to deal with enquiries, installations etc. Again, if you send me a data set where this problem manifests itself, I will try and sort it out. > sorry for bothering you and thank you in advance Hopefully we can get your problems resolved asap. Please send me what you consider to be relevant information (key data sets etc), and we'll progress matters very rapidly. I trust that when all these problems are resolved, that you will broadcast the successful outcome to the CCL. Best regards Martyn ****************************************************************** * Martyn F. Guest * * Computing for Science email: m.f.guest@dl.ac.uk * * c/o CCLRC Daresbury Laboratory FAX : +44 (0)1925 603634 * * Warrington voice: +44 (0)1925 603247 * * Cheshire WA4 4AD * * England, UK * ****************************************************************** From slo1@bnfl.co.uk Fri May 9 07:42:10 1997 Received: from gatekeeper.bnfl.co.uk for slo1@bnfl.co.uk by www.ccl.net (8.8.3/950822.1) id GAA17439; Fri, 9 May 1997 06:48:44 -0400 (EDT) Received: by gatekeeper.bnfl.co.uk; id LAA10473; Fri, 9 May 1997 11:44:32 +0100 Received: from aws004-crl(193.35.4.57) by gatekeeper.bnfl.co.uk via smap (g3.0.3) id xma010471; Fri, 9 May 97 11:44:25 +0100 Received: from APC464 by bnfl.co.uk (5.65/Ultrix4.4-69) id AA09888; Fri, 9 May 1997 11:46:27 +0100 Date: Fri, 9 May 1997 11:46:27 +0100 Posted-Date: Fri, 9 May 1997 11:46:27 +0100 Message-Id: <3.0.16.19970509104425.3647eb3c@aws004> X-Sender: slo1@aws004 X-Mailer: Windows Eudora Pro Version 3.0 (16) To: Fredrik B|kman From: Scott Owens Subject: RSC Modelling group Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Dear all, this message is for members of the Royal Society of Chemistry in the UK. Recently the Industrial Division of the Royal Society of Chemistry has undergone some reorganisation moving from being organised at a regional level to organisation based on subject groups. Several groups such as specialty chemicals and pharmaceuticals are already in existence to represent members interests in those industrial sectors. A group has now been formed to bring together researchers and practitioners in atomistic modelling techniques mostly from an industrial perspective but also welcoming interested academic members. The group is called Molecular Modelling Group and is located within the RSC's industrial division. There will be an inauguration meeting at the RSC's lecture theatre in Burlington Place (off Saville Row) London on Monday 16 June. Speakers will represent a number of industrial companies including ICI, Courtaulds, Unilever and BASF. This will be a one day meeting, with free buffet lunch. Any enquiries about the meeting or the subject group please contact me at one of the addresses below. RSCconf@bnfl.co.uk slo1@bnfl.co.uk ********************************************* The opinions expressed above are those of Scott Owens...... So don't complain to BNFL if you don't like them, because they probably don't like them either. ********************************************** Dr. Scott Owens, Company Research Laboratory, BNFL, B516, Springfields works, Salwick, Preston, PR4 0XJ, UK. Phone: +44 (0)1772 763914 Fax: +44 (0)1772 762470 e-mail slo1@bnfl.co.uk ********************************************* From pis_diez@nahuel.biol.unlp.edu.ar Fri May 9 10:42:00 1997 Received: from biol.unlp.edu.ar for pis_diez@nahuel.biol.unlp.edu.ar by www.ccl.net (8.8.3/950822.1) id KAA20276; Fri, 9 May 1997 10:01:24 -0400 (EDT) Received: from jubert2.biol.unlp.edu.ar (jubert2.biol.unlp.edu.ar [163.10.7.17]) by biol.unlp.edu.ar (8.8.3/8.8.3) with SMTP id LAA06311 for ; Fri, 9 May 1997 11:04:21 -0300 Date: Fri, 9 May 1997 11:04:21 -0300 Message-Id: <199705091404.LAA06311@biol.unlp.edu.ar> X-Sender: pis_diez@nahuel.biol.unlp.edu.ar X-Mailer: Windows Eudora Version 1.4.3 Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" To: chemistry@www.ccl.net From: pis_diez@nahuel.biol.unlp.edu.ar (Reinaldo Pis Diez) Subject: G94, dft, and vshift Dear netters, I've just read the mail sent by Michael Nolan and the answer he received from Martyn Guest concerning convergence problems in TM systems. When one uses dft methods in TM systems the oscillating energy problem is very often found. It is solved by using vshift in G94 calculations for example. But the final electronic configuration doesn't correspond to the true ground state because some empty orbitals have lower energy than some occupied ones. This can be solved by rerunning the calculation using guess=read and eliminating vshift. Now, what does it happen in a geometry optimisation where vshift must be on to achieve convergence, but the orbitals don't correspond to the ground state? Can I trust the optimised geometry and then rerun a single point calculation without vshift to get the correct ground state? I'd appreciate any comments and will summarize to the net. Regards, Reinaldo From chan@uni-muenster.de Fri May 9 10:59:11 1997 Received: from asterix.uni-muenster.de for chan@uni-muenster.de by www.ccl.net (8.8.3/950822.1) id JAA20029; Fri, 9 May 1997 09:42:35 -0400 (EDT) Received: from localhost (chan@localhost) by asterix.uni-muenster.de (8.7.5/8.7.5) with SMTP id PAA140994 for ; Fri, 9 May 1997 15:42:13 +0200 X-Authentication-Warning: asterix.uni-muenster.de: chan owned process doing -bs Date: Fri, 9 May 1997 15:42:13 +0200 (MES) From: "Jerry C.C. Chan" To: chemistry@www.ccl.net Subject: Chemical Softness by DFT 2 Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Hi Netters, Last week I posted a question concerning the determination of chemical hardness (or softness) of the metal centre of a TM complexes. Maybe the way I asked the question was not specific enough, I just received two mails asking for the summary. So I try to write down my thinking explicitly and hope that someone in the net, who could not tolerate the naiveness or even mistakes of my post, would kindly comment on it. I will summarize. I want to determine the chemical hardness of the metal centre of a charged TM complexes. The method that comes to my mind is to do a HF calculation and get the MO spectrum. Based on the Koopmans' theorem the hardness of the complexes would be (E_LUMO - E_HOMO)/2. Even my thinking is correct, HF calculation seems to be unreliable for TM complexes and correlated methods are usually very expensive. Therefore last time I enquired the possibility of using DFT methods as an alternative although Koopman's theorem does not hold for KS orbitals. By the way, I have heard that Fukui function is somehow related to the chemical hardness but I don't have the recipe. Many thanks, Jerry ****************************************************************** * Universitaet Muenster phone: 0049-251-83-29156 * * Institut fuer Physikalische Chemie fax: 0049-251-83-29159 * * Schlossplatz 4-7 * * D-48149 Muenster * * Germany * ****************************************************************** From Y0H8797@ACS.TAMU.EDU Fri May 9 12:42:01 1997 Received: from VMS2.TAMU.EDU for Y0H8797@ACS.TAMU.EDU by www.ccl.net (8.8.3/950822.1) id MAA23105; Fri, 9 May 1997 12:08:09 -0400 (EDT) Date: Fri, 9 May 1997 11:08:10 -0500 (CDT) From: YONG HUANG To: CHEMISTRY@www.ccl.net Message-Id: <970509110810.20497cf1@ACS.TAMU.EDU> Subject: Question to think about during a break Here's a simple question. Is a NaCl molecule (yes, molecule, maybe in gas phase or in a computational chemist's space) a radical? How's the spin density distribution look like if it is? This has nothing to do with my research. Just a question. Yong From cmartin@curie.syr.edu Fri May 9 15:42:07 1997 Received: from curie.syr.edu for cmartin@curie.syr.edu by www.ccl.net (8.8.3/950822.1) id OAA26394; Fri, 9 May 1997 14:51:52 -0400 (EDT) Received: by curie.syr.edu (950413.SGI.8.6.12/940406.SGI.AUTO) id OAA25234; Fri, 9 May 1997 14:09:33 -0700 Date: Fri, 9 May 1997 14:09:33 -0700 Message-Id: <199705092109.OAA25234@curie.syr.edu> From: Charles Martin To: YONG HUANG Cc: CHEMISTRY@www.ccl.net Subject: CCL:Question to think about during a break In-Reply-To: <970509110810.20497cf1@ACS.TAMU.EDU> References: <970509110810.20497cf1@ACS.TAMU.EDU> > Here's a simple question. Is a NaCl molecule (yes, molecule, maybe in gas phase > or in a computational chemist's space) a radical? How's the spin density > distribution look like if it is? This has nothing to do with my research. Just > a question. > Similar question has been addressed by Steve Berry at the University of Chicago a long time ago (at least on some Halide molecules). The ground state changes character from covalent to ionic as the bond is stretched (i.e the typical problem addressed in Landau-Zener hopping). This is a very difficult problem with traditional ab initio methods because most ab initio methods can not treat curve crossings like this properly. Chuck Martin -- ======================================================== || Charles H. Martin || || 2-004 Center for Science and Technology || || W. M. Keck Center for Molecular Electronics || || Department of Chemistry || || Syracuse University || || Syracuse, NY 13244 || -------------------------------------------------------- || cmartin@cat.syr.edu || || cmartin@rainbow.uchicago.edu || || CELL (315) 415-2093 || || OFFICE (315) 443-3754 || || LAB (315) 443-5928 || || FAX (315) 443-4070 || ======================================================== From Y0H8797@ACS.TAMU.EDU Fri May 9 22:42:07 1997 Received: from VMS2.TAMU.EDU for Y0H8797@ACS.TAMU.EDU by www.ccl.net (8.8.3/950822.1) id VAA01236; Fri, 9 May 1997 21:46:08 -0400 (EDT) Date: Fri, 9 May 1997 20:46:10 -0500 (CDT) From: YONG HUANG To: CHEMISTRY@www.ccl.net Message-Id: <970509204610.204a086b@ACS.TAMU.EDU> Subject: NaCl a radical? I guess I didn't make it clear why this is a legitimate question. The reason I ask wheather NaCl is a radical is because a Na atom is closed shell, so Na+ is open shell. Na+Cl- is open shell. If you think NaCl is a Na atom plus a Cl atom without electron transfer, then a Cl atom is open shell so NaCl is still open shell. Yong