From chemistry-request@www.ccl.net Sat Jan 30 10:32:23 1999 Received: from carpincho.overnet.com.ar (carpincho.overnet.com.ar [200.10.96.19]) by www.ccl.net (8.8.3/8.8.6/OSC/CCL 1.0) with ESMTP id KAA28511 Sat, 30 Jan 1999 10:32:20 -0500 (EST) Received: from nppp156.overnet.com.ar (nppp156.overnet.com.ar [200.16.162.164]) by carpincho.overnet.com.ar (8.9.1/8.9.1) with SMTP id MAA21402 for ; Sat, 30 Jan 1999 12:35:47 -0300 Message-Id: <3.0.6.16.19990130122935.37b7e62c@pop.overnet.com.ar> X-Sender: dfa953uo@pop.overnet.com.ar X-Mailer: QUALCOMM Windows Eudora Light Version 3.0.6 (16) Date: Sat, 30 Jan 1999 12:29:35 To: chemistry@www.ccl.net From: "Dr. Daniel Glossman" Subject: Pop=Bonding calculation Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Dear netters: A while ago I've posted a message related to bond orders calculations and the POP=Bonding keyword in Gaussian 94. As I received several requests for summaries but no answers at all, I am (hopefully) posting this again: I have been doing some G94W calculations on several molecules with the POP=Bonding keyword, but I don't know how to do an interpretation of the results and the Gaussian 94 manual is not very informative in this respect. For example, after the title "... Condensed to atoms (all electrons..." I got a symmetric matrix with diagonal elements equal to zero. 1) What do the numbers mean? 2) Where do they come from? 3) Are they related to the so called bond order analysis? 4) Are there any bibliographic references for the calculation of these numbers? After that I got the total atomic charges. These charges are different from those coming from a traditional Mulliken population analysis in that they are not summed up to the charge of the molecule under study. Again, 1) What do these charges mean? 2) What's the meaning of the summation? 3) Where do these numbers come from? 4) which are the bibliographic references? Thanks in advance for a kind consideration of this request. Best regards Dr. Daniel Glossman ***************************************************************************** Universidad Nacional de Lujan Departamento de Ciencias Basicas e-mail: glossman@overnet.com.ar Casilla de Correo 221 phone: (+54) 11 45533797 (6700) Lujan fax: (+54) 11 45539824 Republica Argentina **************************************************************************** ** From chemistry-request@www.ccl.net Sat Jan 30 12:29:42 1999 Received: from harfang.CC.UMontreal.CA (harfang.CC.UMontreal.CA [132.204.2.102]) by www.ccl.net (8.8.3/8.8.6/OSC/CCL 1.0) with ESMTP id MAA28884 Sat, 30 Jan 1999 12:29:41 -0500 (EST) Received: from esi21.ESI.UMontreal.CA (esi21.ESI.UMontreal.CA [132.204.2.91]) by harfang.CC.UMontreal.CA (8.8.8/8.8.8) with ESMTP id MAA17431; Sat, 30 Jan 1999 12:29:42 -0500 (EST) Received: from localhost (proynov@localhost) by esi21.ESI.UMontreal.CA with SMTP id MAA12490 (8.8.7/IDA-1.6); Sat, 30 Jan 1999 12:29:41 -0500 (EST) X-Authentication-Warning: esi21.ESI.UMontreal.CA: proynov owned process doing -bs Date: Sat, 30 Jan 1999 12:29:41 -0500 (EST) From: Proynov Emil X-Sender: proynov@esi21.ESI.UMontreal.CA To: Didier MATHIEU cc: chemistry@www.ccl.net Subject: Re: CCL:SUMMARY: DFT & H-bonds ADDENDUM In-Reply-To: <36B05FE5.183C8837@ripault.cea.fr> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Dear netters, On Thu, 28 Jan 1999, Didier MATHIEU wrote: > Hi, > > Many people asked me to summarize the replies to my question concerning > the performance of DFT, and especially early functionals such as > Becke-Perdew86, with regard to the description of the energetic of > H-bonds. > Clearly, everybody agree that hybrid functionals are better than GGA > functionals, the latter being themselves much better than LDA. Recently, > the team by Salahub has developped a LAP functional which performs well. > Somebody also pointed to the need for extended basis sets for > convergence. I would like just to add here some references about the LAP functionals mentioned above: I would recommend examining particularly refs. [4-6] enclosed below, from which it can be envisaged that the hybrid methods may not alwas be a panacea as far as intra-molecular hydrogen bonds concern and perform a bit worse than the Lap Exc schemes. Moreover, while the hybrid methods seems to be indeed more demanding towards basis set convergence (keeping in mind that in Gaussian the basis set used is HF-based optimized not DFT-base optimized), the pure DFT codes like deMon deMol and Dgauss use basis sets that are specially optimized and adapted to DFT numerics (which leads to less convergence demands and smaller bsse errors on average) I particularly find that the old good GGA BP is not that bad for systems like H2O dimer and HF dimer as far as energetics concern (it just gives a bit shorter O...H and F...H distances) LAP references: [1]. E.I. Proynov and D.R. Salahub, Phys.Rev.B v.49, 7874 (1994) ; Erratum, ibid. v.57, 12616 (1998). [2] E. Proynov, A. Vela and D. R. Salahub, Chem.Phys.Lett. vol.230, 419 (1994); Erratum, ibid., vol 234, 462 (1995). [3] E.I. Proynov, E. Ruiz, A. Vela, and D.R. Salahub, Int. J. Quant. Chem.(Symp.) vol 29, 61 (1995); [4] E. I. Proynov, S. Sirois and D. R. Salahub, Int. J. Quant. Chem.vol.64, 427, (1997). [5] S. Sirois, E. Proynov, D. Nguyen and D.R. Salahub, J.Chem.Phys. v107, 6770 (1997). [6] H. Guo, S. Sirois, E. Proynov, and D.R. Salahub, in: "Density Functional Theory and Its Applications to Hydrogen Bonded Systems" Theoretical treatment of Hydrogen Bondings}, H; Hadzi ed. John Willey (1997). Best wishes to all, Emil Proynov +-----------------------------+ | Dr Emil Proynov | | Post-doc | | proynov@chimie.umontreal.ca | | eproynov@scf.fundp.ac.be | +-----------------------------+ > > With regard to the performance of early functionals, I retain from the > answers that the results provided by functonals such as BP for weak > bonds are fairly erratic. > > Finally, in view of the wealth of answers pointing to new functionals, > especially hybrid ones, BP appears old-fashioned. > In fact, we used this functional for the sake of comparison with > previous work, where we replaced BP geometries with molecular mechanics > MMFF structures. > > Regards > > -- > Didier MATHIEU > CEA - Le Ripault, BP 16 > 37260 Monts (France) > Tel. 33(0)2.47.34.41.85 > > -------This is added Automatically by the Software-------- > -- Original Sender Envelope Address: chemistry-request@www.ccl.net > -- Original Sender From: Address: mathieu@ripault.cea.fr > CHEMISTRY@www.ccl.net: Everybody | CHEMISTRY-REQUEST@www.ccl.net: Coordinator > MAILSERV@www.ccl.net: HELP CHEMISTRY or HELP SEARCH | Gopher: www.ccl.net 73 > Anon. ftp: www.ccl.net | CHEMISTRY-SEARCH@www.ccl.net -- archive search > Web: http://www.ccl.net/chemistry.html > +-----------------------------+ | Emil Proynov | | proynov@chimie.umontreal.ca | +-----------------------------+