From grzesb - at - asp.biogeo.uw.edu.pl Fri Nov 25 05:22:13 1994 Received: from asp.biogeo.uw.edu.pl for grzesb $#at#$ asp.biogeo.uw.edu.pl by www.ccl.net (8.6.9/930601.1506) id EAA18199; Fri, 25 Nov 1994 04:25:38 -0500 Received: by asp.biogeo.uw.edu.pl (5.61/1.34) id AA22132; Fri, 25 Nov 94 10:29:13 +0100 Date: Fri, 25 Nov 94 10:29:13 +0100 From: grzesb { *at * } asp.biogeo.uw.edu.pl (Grzegorz Bakalarski) Message-Id: <9411250929.AA22132(-(at)-)asp.biogeo.uw.edu.pl> To: CHEMISTRY # - at - # ccl.net Subject: SUMMARY: Mulliken Population Analysis and Basis Sets Dear CCLNet, Last Monday I asked a question on how much charges from Mulliken population analysis can depend upon basis set, especially using diffusive functions. Thanks to all you who replied. I think that every suggestion is worth reading. Thank a lot Yours sincerely Grzegorz Bakalarski Warsaw University Poland _________________________________________________________ This is summary of replies I've got until Friday morning: ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Original query: Dear Netters, Maybe this is a very naive question, but .... I'd like to ask you Dear Quantum Chemists, how much charges from Mulliken population analysis can depend upon basis set ? Particular problem is that I and coworkers have calculated Mulliken charges using different programs using different basis sets e.g.. gaussian 6-31G** basis set ( in GAUSSIAN) and double numerical with polarization basis set (DNP in DMol). And of course we've got different Mulliken charges. (As we've expected and as it is well know that Mulliken charges depend on basis sets). But we've noticed that for some atoms differences are quite large. For example when a methyl group is bound to nitrogen atom changes are about 0.7-0.8 e (6-31G** : -0.188 [MP2] ;-0.193 [B3-LYP] and DNP: -0.962 [LDF]; -0.786 [NLDF]). I'd like to ask especially about comparison between DNP and gaussian + diffusive basis sets, because as I know numerical basis sets are "more diffusive" than gaussian ones (they have "good tails"). I'd like to add that we've also calculated ESP charges and they are O.K. (differences less than 0.1 e), that means that electron density is calculated correctly. Any comments, references and hints would be nice. Thanks in advance for anyone who replies. If I get any useful information I'll summarize to the NET. Best wishes and have a nice week. Grzegorz Bakalarski Dept. of Biophys. UW & Interdisciplinary Centre for Modelling (ICM) Warsaw University Poland e-mail: grzesb #*at*# asp.biogeo.uw.edu.pl $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ R E P L I E S $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ From: Ferenc.Molnar "-at-" chemie.uni-regensburg.de (Ferenc Molnar) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ There is a very nice review related to this topic: Reviews in Computational Chemistry, Vol. 5, Libkowitz, Boyd (Eds.). I can't remember by whom it was, right now, but if you look in the book you will surely find it. The author favors Loevdin populations over Mulliken populations and discusses the "atoms in molecules" approach by Baader. The shortcomings of each method are discussed! Hope this helps, Ferenc Molnar Institut fuer Physikalische und Theoretische Chemie - Lehrstuhl Prof. Dick - Tel.: (+49) 941 943-4466 /-4486 Universitaet Regensburg Fax.: (+49) 941 943-4488 Universitaetsstrasse 31 D-93053 Regensburg Deutschland / Germany &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& From: "Erin Duffy" ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Hi - You might want to take a look at the following: (1) Carlson, HA; Nguyen, TB; Orozco, M.; Jorgensen, WL. "Accuracy of Free Energies of Hydration for Organic Molecules from 6-31G(d)-Derived Partial Charges." J. Comput. Chem. (1993) v.14, 1240-1249. (2) Wiberg, KB; Rablen, PR. "Comparison of Atomic Charges Derived via Different Procedures." J. Comput. Chem. (1993) v.14, 1504-1518. Ciao - Erin erin "-at-" lorentz.csb.yale.edu (Erin Duffy) &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& From: "FOUNTAIN, KEN" ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ The answer is "Lots!" In Gaussian computations fluctuations abound, depending on the level of theory. In fact the entire area of populations seems to be murky. &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& From: "Robert K. Szilagyi" indy.mars.vein.hu> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Dear Dr. Grzegorz Bakalarski, we found some systematical changes in Mulliken Population analysis while varying basis sets. Our system contains transition metal and we are utilizing effective core potentials. The magnitude of the charges was changed, the inductive effects, electrophility, etc. remain the same. I will send you a note if this article will accepted by the publisher. Sincerely Yours, Rob Robert K. Szilagyi University of Veszprem METMOD FF research fellow Dept. Org. Chem. L1 Email: szilagyi at.at miat0.vein.hu Veszprem, H-8201 L2 | R1 szilagyi { *at * } indy.mars.vein.hu Egyetem u. 10 >W=C< Phone: +36-(88)-422022/156 P.O.Box 158 L3 | R2 FAX: +36-(88)-426016 HUNGARY L4 &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& From: young \\at// slater.cem.msu.edu (Dave Young) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Hello, There was a question about basis set dependence of the mulliken population analysis. Generally, the answer is that there is a basis set dependence and it is often very large. The arbitrary 50-50 split of overlap populations makes some sense for minimal basis sets and covalent compounds. For ionic compounds, 50-50 split should be suspect immediately. With diffuse basis sets, the diffuse functions may be so far from the nucleus they are centered on that they are describing the other nuclei more than the one they are centered on. Somewhat better results are obtained with the Reid & Weinhold natural orbital analysis. Probably the least basis set dependent results come from the electrostatic analysis in which atomic charges are determined by a least squares fit to the electrostatic potential. Hope this helps. Dave Young young-: at :-slater.cem.msu.edu youngdc[ AT ]msucem &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& From: evaldera \\at// amadeus.ivic.ve (Elmer Valderrama) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Hi, Just in case you haven't check this source, I. Levine in "Quantum Chemistry" (1991) wrote: `One should not put too much reliance on numbers calculated by population analysis. Mulliken's assignment of half the overlap population to each basis function is arbitrary and sometimes leads to unphysical results (see Mulliken & Ermler, Diatomic Molecules, (1977) p. 36-38, 88-89). Moreover, a small change in basis set can produce a large change in the calculated net charges. For example, net charges on each H atom in CH4, NH3, and H2O calculated by the STO-3G and 3-21G basis set are (Hehre et al. Ab Initio Molecular Orbital Theory (1986), Sec. 6.6.2) CH4 NH3 H2O ----------------------- STO-3G 0.06 0.16 0.18 3-21G 0.20 0.28 0.36 Comparison of values calculated with the same basis set correctly shows increasing charge on each H atom as the electronegativity increases from C to N to O, but comparison of the values calculated with different basis sets could erroneously lead one to say that the C-H bond in CH4 is more polar than the O-H bond in H2O." "Many other methods have been proposed to assign charges to atoms in molecules. See P. Polizer et al. Theor.Chim. Acta 38 101 (1975); J. Cioslowsky, J.Am.Chem.Soc 111 8333 (1989); Hehre, Sec. 6.6.2)" -What follows is that you could carry out a detailed analysis of the results from both DNP and n-nnG type calcns but since no unitary transformation connect these wave functions, all would be reduced to just a basis-set-dependent effect. Elmer &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& From: inoue()at()greencross.co.jp (Yoshihisa Inoue) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Dear Dr. Grzegorz Bakalarski, I think Mulliken population analysis is historically important, but actually sometimes perplexes researchers. As you know, the charges are used for molecular dynamics or monte carlo calculations. Then, I think they should have physicochemical meaning. Following two reports might be useful for you. TI Comparison of Atomic Derived via Different Procedures AU Kenneth B. Wiberg and Paul R. Rablen SO J.Comp.Chem.,14(12), 1504-1518 (1993) TI Electron Density Distribution Analysis for Nitromethane, Nitromethide, and Nitramide AU James P. Ritchie SO J.Am.Chem.Soc.,107,1829-1837 (1985) The former examined the charges with physicochemical properties. You seems to use DMol, so I suggest to use Hirshfeld charges. We also reported that Hirshfeld charges are very good at WATOC'93 at Toyohashi, Japan. Dr.Ritchie made Rhosys and it can handle gaussian basis functions. According to the JACS report, he provided the program. And Drs.Wiberg and Rablen wrote that the Hirshfeld charges were obtained using programs written at Yale. Hope this help. ____/ ___/ ___/ Yoshihisa INOUE (^_^) the Green Cross Corp. / / / 2-25-1 Shodai-Ohtani,Hirakata,Osaka 573 JAPAN / _ / / / tel: +81-720-56-9328 / / / / fax: +81-720-68-9597 _____/ _____/_____/ E-mail: inoue(-(at)-)greencross.co.jp $$$$$$$$$$$$$$$$$$$$$$$$$$$$ T H E E N D $$$$$$$$$$$$$$$$$$$$$$$$$$$$$