From moshe_o { *at * } VNET.IBM.COM Sun Nov 26 08:53:02 1995 Received: from VNET.IBM.COM for moshe_o $#at#$ VNET.IBM.COM by www.ccl.net (8.6.10/950822.1) id IAA15446; Sun, 26 Nov 1995 08:38:39 -0500 Message-Id: <199511261338.IAA15446()at()www.ccl.net> Received: from HAIFASC3 by VNET.IBM.COM (IBM VM SMTP V2R3) with BSMTP id 2595; Sun, 26 Nov 95 08:38:32 EST Date: Sun, 26 Nov 95 14:45:00 IST From: "Moshe Olshansky" To: chemistry <-at-> www.ccl.net Subject: Combining different basis sets - a summary Dear netters! About 10 days ago I asked the following question: > Dear CCL'ers! > We are working on computational aspects of the Hartree-Fock procedure. > For this purpose we would like to have some f-type basis functions > but not too many of them, while all the basis sets we have either > do not have f functions at all or have too many of them (our trial > molecule contains H C N and O atoms). > Since we are not chemists I would like to ask the following > (possibly very trivial) question: does it make any sense to combine > two different basis sets (for example, take a smaller basis set for > H and C and a larger one - containing d and f functions - for N and O)? First of all, I wish to thank all those who replied to this questions. Basically I got two kinds of responses: some stress the dangers of doing so (talking about Basis Set Superposition Error, etc.), while others say it can (and is being) done, though some caution is needed. Below are the responses I got. Moshe Olshansky IBM Israel Science and Technology vnet.ibm.com> ========================================================================= Date: Tue, 14 Nov 1995 17:46:52 +0100 From: aiba $#at#$ ir.phys.chem.ethz.ch (Ayaz Bakasov, Phys. Chem., ETH Zurich) To: moshe_o "-at-" vnet.ibm.com Subject: Re: CCL:Combining different basis sets Dear Mosche, that naive idea of combining (straightforwardly) arbitrary basis sets is not so harmless as it could seem at first glance. The dangers have been recognized long ago, and have been discussed, for instance, in chapter 18 "Balancing basis sets" (page 333) of the following review: Sigeru HIZINAGA "Basis sets for molecular evaluations" Computer Physics Reports 2 (1985) 279-340. The error caused by an unbalanced basis set is normally called "basis set superposition error". The best, Ayaz Bakasov. P.S. Na pal'tsakh: slishkom bol'shoi basis na kakom-libo atome "otsasyvaet" neproportsional'no bol'shoi ob'em volnovoi funktsii na etot atom. ========================================================================= Date: Tue, 14 Nov 95 12:21:32 EST From: "Janet Del Bene" Subject: Your question - Moshe, You did not state specifically the problem of interest, but I am sure that you are aware that there is a basis-set dependence of computed results. To arbitrarily put a larger basis set on some atoms and smaller sets on others would bias your results. Hope this helps. Janet E. Del Bene ========================================================================= Date: Tue, 14 Nov 1995 18:52:45 +0100 From: mas -AatT- qc.ag-berlin.mpg.de (Marek Sierka) Message-Id: <9511141752.AA18630 \\at// gea.qc.ag-berlin.mpg.de> Subject: Basis Set Dear Moshe, Good basis set has to be properly balanced, otherwise it introduces so called Basis Set Superposition Error. In case of the unbalanced basis set, it leads to the artificial charge transfer, and also gives nonphysical, stabilizing contributions to the enery of molecule. This stabilizing will then occure irrespective of whether there is any genuine binding interaction in the molecule or not. It will give a spurious increase in the binding energy.The choice of proper basis set is kind of art, so you have to be very careful about it. Try this: http://www.emsl.pnl.gov:2080/forms/basisform.html This www server contains several basis sets, so maybe you can find something useful. Marek Sierka Max-Planck Society Quantum Chemistry Group at the Humboldt Univ. Joegerstrasse 10/11 D-10117 Berlin, Germany e-mail: mas -8 at 8- gea.qc.ag-berlin.mpg.de ========================================================================= Date: Tue, 14 Nov 1995 13:23:54 -0500 From: "E. Lewars" Subject: COMBINING BASIS SETS Hello, Yes, you can combine basis sets. For example, the 3-21G* basis has d orbotals on atoms beyond Ne, bot no d's on H--Ne. Some people would call it an "untempered" or uneven basis set, but it works well (see *Practical Strategies for Electron Structure Calculations*, by Warren Hehre, 1995). Also, in papers in on oxirenes, I think Schaefer and coworkers used f and maybe g functions on some atoms but not other: J Phys Chem 98 (1994) 8660 J Am Chem Soc 116 (19940 9311 j aM cHEM sOC 116 (1994) 10159 oF COURSE, THE WIDELY-USED 6-31g* basis has d functions on He, Li, Be, etc, but not on H, and 6-31G** has p's on H but d's on He, Li, etc. Errol Lewars ========================================================================= From: David Heisterberg Date: Tue, 14 Nov 1995 13:35:35 -0500 Subject: Re: CCL:Combining different basis sets There is a school of thought that says that basis sets should be similar for each atom, or at least similar for all important atoms, such as those involved in bond breaking/making. This is especially important if you are interested in any basis-set dependent information, such as partial charges. But it might also be important for a purely computational study -- during the SCF, an "unbalanced" basis-set might exhibit changes in the density matrix that are really just artifacts, and wouldn't appear as significant changes in the Fock matrix. I would suggest looking at the basis sets available from PNL, especially the so-called correlation consistent (cc) sets. The cc-pVTZ set for C, N, and O are of the form (4S,3P,2D,1F). They are web-accessible at http://www.emsl.pnl.gov:2080/forms/basisform.html Dave Heisterberg ========================================================================= From: Jiri Czernek Subject: Re: CCL:Combining different basis sets Date: Tue, 14 Nov 1995 20:30:42 +0100 (MET) Hi again ! :-) I think you risc the basis set for your molecule will be ILL-BALANCED. For explanation I'll cite from some book by Huzinaga: "If basis sets of different quality are placed on atomic sites of a molecular system, the calculated electron distribution may show artificial distortion. Improperly balanced basis sets may yield results even worse than basis sets of uniformly poorer quality." Hope this helps :-) Cordially , George ========================================================================= From: bschmitz &$at$& chm.uri.edu Date: Tue, 14 Nov 1995 17:28:00 EST Subject: basis sets Hi Dr. Olshansky, You are apt to get two very different responses to this question. From a purist's point of view differeent basis sets probably shouldn't be combined but from a practical point of view its often necessary. I'm assuming by d and f type functions you mean d and f type gaussians. These are frequently treated as "polarization" functions and are often added to some atoms in a molecule but not others. They are almost always necessary to accurately model the behavior of nitrogen and oxygen atoms. Because we have such a small computer here at URI we often have to combine basis sets. To toot my own horn: A Comparitive Theoretical Study of Hydrazine", Brian K. Schmitz and William B. Euler, Journal of Molecular Structure(Theochem), 257, 1992, 227. Here are some other references I have to hand: Binkley, J. S.; Pople, J.A.; Hehre, W.; Self-Consistent Molecular Orbital Methods. XII. Further Extensions of Gaussian Type Basis Sets for Use in Molecular Orbital Studies of Organic Molecules, Journal of the American Chemical Society, 1980, 102, 939. Boys, S. F.; Electronic-Wave Functions I. A General Method of Calculation for the Stationary States of Any Molecular System, Proceedings of the Royal Society (London), 1950, A200, 542. Defrees, D. J.; Raghavachari, K.; Schlegel, H. B.; Pople, J.A.; Effect of Electron Correlation on Theoretical Equilibrium Geometries. 2. Comparison of Third-Order Perturbation and Configuration Interaction Results with Experiment, Journal of the American Chemical Society, 1982, 104, 5576. Ditchfield, R.; Hehre, W.J.; Pople, J.A.; Self-Consistent Molecular-Orbital Method.IX. An Extended Gaussian-Type Basis for Molecular Orbital Studies of Organic Molecules, Journal of Chemical Physics, 1971, 54, 724. Dunning, T. H.; Gaussian Basis Functions for Use In Molecular Calculations. I. Contraction of Atomic Basis Sets for First Row Atoms, Journal of Chemical Physics, 1970, 53, 2823. Hariharan, P. C.; Pople, J. A.; The influence of polarization Functions on Molecular Orbital hydrogenation Energies, Theoretica Chimica Acta, 1973, 28, 213. Hinchliffe, A.; Ab Initio Determination of Molecular Properties, IOP Pub., ltd., England , 1987, 9. Huzinaga, S.; Gaussian-Type Functions for Polyatomic Systems.I., Journal of Chemical Physics, 1965, 2, 1293. Jensen, J. H.; Gordon, M. S.; Splicing I. Using Mixed Basis Sets in ab initio Calculations, Journal of Computational Chemistry, 1991, 12, 421. Klopper, W.; Kutzelnigg, W.; Gaussian Basis Sets and the Nuclear Cusp Problem, Jorunal of Molecular Structure(Theochem), 1986, 28, 339. Krishnan, R.; Binkley, J.S.; Seeger, R.; Pople, J.A.; Self-consistent Molecular Orbital Methods. XX. A Basis Set for Correlated Functions, Journal of Chemical Physics, 1980, 72, 650. Ohta, K.; Nahatsuji, H.; Hirao, K.; Yonezawa, T.; Ab initio Calculation of Hyperfine Splitting Constants of Molecules, Journal of Chemical Physics, 1980, 73, 1770. Poirier, R.; Kari, R.; Csizmadia, I. G.; Handbook of Gaussian Basis Sets, 1985, Elsevier, New York, Appendix F. Pulay, P.; Fogarasi, G.; Pang, F.; Boggs, J. E.; Molecular Geometries, Force Constants, and Dipole Moment Derivatives, Journal of the American Chemical Society, 1979, 101, 2550. Pulay, P.; Fogarsi, G.; Pongor, G.; Boggs, J.; Varga, A.; Journal of the American Chemical Society, 1983, 105, 7037. Riggs, N. V.; Radom, L.; The 3-21G(N*) Basis Set: An Economical Polarized Basis set for ab initio Studies on Nitrogen Containing Molecules, International Journal of Quantum Chemistry, 1987, 31, 93. Riggs, N. V.; Radom, L.; An ab initio Investigation of the Equilibrium Structures of Hydrazine and the Transition Structures Connecting Them, Australian Journal of Chemistry, 1986, 39, 1917. Shavitt, I.; Methods in Computational Physics, Vol. 2, eds. Alder, B.; Fernbach, S.; Rothenburg, M; Academic Press, New York, NY, 1963, 3. Yours truly, Brian Schmitz e-mail: BSchmitz -8 at 8- chm.uri.edu ========================================================================= Date: Tue, 14 Nov 95 19:02:39 -0330 From: cory(-(at)-)bohr.chem.mun.ca (Cory C. Pye) Subject: Basis sets For molecules containing only H, C, N, and O atoms, for a Hartree-Fock calculation you probably don't need d or f-functions for C, since C is (usually) in a fairly symmetric environment (especially sp3 carbons). They might come in handy for an sp2 or sp carbon to help describe the pi-bonds. Oxygen and Nitrogen should definitely have d-functions, and in some of my work on BSSE (C. C. Pye, R. A. Poirier, D. Yu and P. R. Surjan, {\em J. Mol. Struct. (Theochem)}, {\bf 307} (1994) 239 ), they were somewhat important for Nitrogen (f-functions, that is). I think as long as the occupied s & p functions are consistent for different atoms, you probably won't have to worry about unbalanced basis sets too much. So from best to worst: C df, N df, O df H p C d , N df, O df H p C d , N df, O d H p C d , N d , O d H p C d , N d , O d N d , O d (probably) Hope this helps a bit. -Cory ************* ***************** ! Cory C. Pye *** ** ** ** ! Graduate Student ** * **** ! Unpaid Sys Admin ** * * ! Theoretical and ** * * ! Computational Chemistry *** * * ** ! ***************** ! Les Hartree-Focks ************* ! (Apologies to Montreal Canadien Fans) ========================================================================= From: Christopher J Cramer Subject: Re: CCL:Combining different basis sets Date: Tue, 14 Nov 1995 17:06:51 -0600 (CST) Moshe, > > We are working on computational aspects of the Hartree-Fock procedure. > For this purpose we would like to have some f-type basis functions > but not too many of them, while all the basis sets we have either > do not have f functions at all or have too many of them (our trial > molecule contains H C N and O atoms). > Since we are not chemists I would like to ask the following > (possibly very trivial) question: does it make any sense to combine > two different basis sets (for example, take a smaller basis set for > H and C and a larger one - containing d and f functions - for N and O)? > Particularly with respect to polarization functions, I believe that you are correct in your assumption that they may be more important on some atoms than on others. This is in fact widely accepted (if not necessarily consciously) when one refers to atoms from different rows (e.g., 6-31G* puts polarization functions on C but not H, 3-21G(*) puts polarization functions on P but not C, etc.) It is much less common to discriminate between atoms within the same row. However, we ourselves have recently optimized a variation of the MIDI basis set (we call it MIDI! "midi-bang") with the goal of developing a small basis set that gives high quality geometries and atomic partial charges from HF calculations. In that process, we discovered that d functions on C were unimportant even though they were critical for N and O (this for a test set spanning a wide range of organic functionalities). Of course, we are interested in properties other than the total energy, where we have not tested the utility of the basis set (mind you, it will probably perform no more poorly than any other small basis set). So, with some judicious comparisons made first, I would say that you can legitimately tailor your polarization space to suit your needs without fear of catastrophic consequences. Chris -- Christopher J. Cramer University of Minnesota Department of Chemistry 207 Pleasant St. SE Minneapolis, MN 55455-0431 -------------------------- Phone: (612) 624-0859 || FAX: (612) 626-7541 cramer -8 at 8- maroon.tc.umn.edu http://dionysus.chem.umn.edu/ ========================================================================= From: Marcelo Giordan Santos Subject: Combinning Different Basis Sets. Date: Wed, 15 Nov 1995 12:34:21 -0200 (EDT) Dear Mosche, There are many examples in the literature, that combine different kinds of basis sets, even among the same element. In my opinion there is no problem in mixing different basis sets of different degree of quality for the same molecule. But, you should examine your results in the light of this apporach. I've an article about pyrrolizidine alkaloids in which i mix different kinds of basis sets, utilizing pseudopotential and all-electrons approach. It will appear in the fortcomming numbers of J. Comp. Chem. Best regards, Marcelo Giordan. -- &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& & Marcelo Giordan & EDM - Faculdade de Educacao - USP & Av. da Universidade 309, & Cid. Universitaria, Sao Paulo, S.P. & CEP: 05508-900 , Brazil & & ##################################### & e-mail: giordan -x- at -x- usp.br & voice: 55-11-8150297 & fax: 55-11-8183149 & & &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&