From chemistry-request@ccl.net Mon May 26 12:34:01 2003 Received: from guanin.uni-konstanz.de (guanin.uni-konstanz.de [134.34.240.5]) by server.ccl.net (8.12.8/8.12.8) with ESMTP id h4QGY1KY013614 for ; Mon, 26 May 2003 12:34:01 -0400 Received: from charlie (charlie.chemie.uni-konstanz.de [134.34.110.118]) by guanin.uni-konstanz.de (Postfix) with ESMTP id 9079326A46D for ; Mon, 26 May 2003 18:33:47 +0200 (MEST) Message-ID: <200305261833590671.0F6D9487|at|mailhub.uni-konstanz.de> X-Mailer: Calypso Version 3.30.00.00 (1) Date: Mon, 26 May 2003 18:33:59 +0200 Reply-To: eike.huebner|at|uni-konstanz.de From: "pop14848" To: "CCL" Subject: CCL: HOMO/LUMO gap Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by server.ccl.net id h4QGY1KY013615 Hi, I did some DFT calculations on transition metal complexes using the 6-31G* basis set, Hay-Wadt effective core potential on the transition metal (mainly Ru) and the BP86 functional. The HOMO-LUMO energy gaps are too small (e.g. 1000nm instead of 460nm) in comparison to HF calculations where the predicted HOMO-LUMO gaps are far too large. Can someone point me to quotable papers where the reasons for the too small gaps are discussed? I really need published papers and not a list of reasons. Thanks in advance Eike Huebner From chemistry-request@ccl.net Mon May 26 15:02:09 2003 Received: from soul.helsinki.fi (soul.helsinki.fi [128.214.3.1]) by server.ccl.net (8.12.8/8.12.8) with ESMTP id h4QJ27KY016951 for ; Mon, 26 May 2003 15:02:08 -0400 Received: from localhost (mpjohans@localhost) by soul.helsinki.fi (8.9.3p2/8.9.3) with ESMTP id WAA332068; Mon, 26 May 2003 22:02:05 +0300 (EEST) X-Authentication-Warning: soul.helsinki.fi: mpjohans owned process doing -bs Date: Mon, 26 May 2003 22:02:05 +0300 (EEST) From: Mikael Johansson X-X-Sender: mpjohans*at*soul.helsinki.fi To: pop14848 cc: CCL Subject: Re: CCL:HOMO/LUMO gap In-Reply-To: <200305261833590671.0F6D9487*at*mailhub.uni-konstanz.de> Message-ID: References: <200305261833590671.0F6D9487*at*mailhub.uni-konstanz.de> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Hello Eike and All! On Mon, 26 May 2003, pop14848 wrote: > I did some DFT calculations on transition metal complexes using the > 6-31G* basis set, Hay-Wadt effective core potential on the transition > metal (mainly Ru) and the BP86 functional. The HOMO-LUMO energy gaps are > too small (e.g. 1000nm instead of 460nm) in comparison to HF > calculations > where the predicted HOMO-LUMO gaps are far too large. Can someone point > me to quotable papers where the reasons for the too small gaps are > discussed? I really need published papers and not a list of reasons. I don't know what would be a proper "first reference" to the problem, but more recent ones are easier to find (as people try to cure the disease). Two examples: J. Garza et.al., J.Chem.Phys. 114 (2001) 639-651. C-G. Zhan et.al, J.Phys.Chem A 107 (2003) 4184-4195. Have a nice day, Mikael J. http://www.helsinki.fi/~mpjohans/ From chemistry-request@ccl.net Mon May 26 20:39:03 2003 Received: from cascara.uvic.ca (cascara.uvic.ca [142.104.5.28]) by server.ccl.net (8.12.8/8.12.8) with ESMTP id h4R0d3KY024241 for ; Mon, 26 May 2003 20:39:03 -0400 Received: from [24.68.208.249] ([24.68.208.249]) by cascara.uvic.ca (8.12.9/8.12.9) with ESMTP id h4R0csMq655958 for ; Mon, 26 May 2003 17:38:55 -0700 From: Roy Jensen To: chemistry|at|ccl.net Subject: 'electron density' vs 'electronic configurations'... Date: Mon, 26 May 2003 17:40:05 -0700 Message-ID: <1vc5dvsgb9me1hhadkauvah18q291sjst4|at|4ax.com> X-Mailer: Forte Agent 1.91/32.564 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-UVic-Virus-Scanned: OK - Passed virus scan by Sophos (sophie) on cascara X-UVic-Spam-Status: No X-UVic-Spam-Score: -2.9 USER_AGENT_FORTE X-UVic-Spam-Level: Spam-Level X-Scanned-By: MIMEDefang 2.33 (www . roaringpenguin . com / mimedefang) Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by server.ccl.net id h4R0d3KY024242 All The following came up recently and we could not come to a conclusion. One premise behind DFT is that a _single_ electron density completely describes each electronic state of a system. In ab initio systems, _all_ electronic configurations contribute to the wavefunction for each electronic state of a system. Is this an artifact of the approximations in ab initio calculations? Alternatively, if described exactly, is an exact ab initio wavefunction still composed of all the electronic configurations? On a second point, would it be correct to say that DFT _variationally_ optimizes the electron density to determine the minimum energy of the system? Thanks, Roy Jensen From chemistry-request@ccl.net Mon May 26 03:47:01 2003 Received: from cascara.uvic.ca (cascara.uvic.ca [142.104.5.28]) by server.ccl.net (8.12.8/8.12.8) with ESMTP id h4Q7l1KY000847 for ; Mon, 26 May 2003 03:47:01 -0400 Received: from [24.68.208.249] ([24.68.208.249]) by cascara.uvic.ca (8.12.9/8.12.9) with ESMTP id h4Q7ksY7337824 for ; Mon, 26 May 2003 00:46:54 -0700 From: Roy Jensen To: chemistry/at/ccl.net Subject: 'electron density' vs 'electronic configurations'... Date: Mon, 26 May 2003 00:47:58 -0700 Message-ID: X-Mailer: Forte Agent 1.91/32.564 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-UVic-Virus-Scanned: OK - Passed virus scan by Sophos (sophie) on cascara X-UVic-Spam-Status: No X-UVic-Spam-Score: -2.9 USER_AGENT_FORTE X-UVic-Spam-Level: Spam-Level X-Scanned-By: MIMEDefang 2.33 (www . roaringpenguin . com / mimedefang) Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by server.ccl.net id h4Q7l1KY000848 All The following came up recently and we could not come to a conclusion. One premise behind DFT is that a _single_ electron density completely describes each electronic state of a system. In ab initio systems, _all_ electronic configurations contribute to the wavefunction for each electronic state of a system. Is this an artifact of the approximations in ab initio calculations? Alternatively, if described exactly, is an exact ab initio wavefunction still composed of all the electronic configurations? On a second point, would it be correct to say that DFT _variationally_ optimizes the electron density to determine the minimum energy of the system? Thanks, Roy Jensen From chemistry-request@ccl.net Mon May 26 14:01:22 2003 Received: from mx3.trentu.ca (mx3.trentu.ca [192.75.12.4]) by server.ccl.net (8.12.8/8.12.8) with SMTP id h4QI1MKY015760 for ; Mon, 26 May 2003 14:01:22 -0400 Received: (qmail 30909 invoked by uid 504); 26 May 2003 18:01:21 -0000 Received: from elewars/at/trentu.ca by mx3.trentu.ca by uid 501 with qmail-scanner-1.14 (fsecure: 4.15/4370/2003-05-23/2003-05-23. 2003-05-22/ Clear:. Processed in 0.297828 secs); 26 May 2003 18:01:21 -0000 X-Qmail-Scanner-Mail-From: elewars/at/trentu.ca via mx3.trentu.ca X-Qmail-Scanner: 1.14 (Clear:. Processed in 0.297828 secs) Received: from unknown (HELO trentu.ca) (209.42.101.30) by mx3.trentu.ca with SMTP; 26 May 2003 18:01:20 -0000 Message-ID: <3ED25732.3396BA1C/at/trentu.ca> Date: Mon, 26 May 2003 14:04:35 -0400 From: elewars X-Mailer: Mozilla 4.79 [en] (WinNT; U) X-Accept-Language: en MIME-Version: 1.0 To: pop14848 , chemistry/at/ccl.net Subject: Re: CCL:HOMO/LUMO gap, response References: <200305261833590671.0F6D9487/at/mailhub.uni-konstanz.de> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit 2003 May 26 Hello, I don't have a specific ref to your H/L gap problem, but you may find a ref in one of the following: 1) Visit the CCL archives and find 11 Feb 2002, Summary by Per-Ola Norrby "High level for TMs" 2) Visit the CCL archives and find 27 Nov 2001, Summary by Meike Reinhold "B3LYP vs B3P86" 3) G. Frenking et al, Rev in Comp Chem, 8, 63-143 (1996) 4) P. E. M. Siegbahn, "Electronic Structure Calculations for Molecules Containing Transition Metals", Advances in Chemical Physics, vol XCIII, Wiley, New York, 1996. (he says ab in. is not as bad as had been thought). 5) "Comparison of DFT with ab in. ...first transition row metals..." Theor Chem Acta, 92, 123-131 (1995). Note that the orbitals (and thus the gap) are not quite the same _thing_ for DFT as for ab in.: R. Stowasser and R. Hoffmann, JACS, 121, 3414 (1999) and refs therein. This ref may have a clue to your problem. E. Lewars ===== pop14848 wrote: > Hi, > > I did some DFT calculations on transition metal complexes using the 6-31G* basis set, Hay-Wadt effective core potential on the transition metal (mainly Ru) and the BP86 functional. The HOMO-LUMO energy gaps are too small (e.g. 1000nm instead of 460nm) in comparison to HF calculations where the predicted HOMO-LUMO gaps are far too large. Can someone point me to quotable papers where the reasons for the too small gaps are discussed? I really need published papers and not a list of reasons. > > Thanks in advance > > Eike Huebner > > -= This is automatically added to each message by mailing script =- > To send e-mail to subscribers of CCL put the string CCL: on your Subject: line > and send your message to: CHEMISTRY/at/ccl.net > > Send your subscription/unsubscription requests to: CHEMISTRY-REQUEST/at/ccl.net > HOME Page: http://www.ccl.net | Jobs Page: http://www.ccl.net/jobs > > If your mail is bouncing from CCL.NET domain send it to the maintainer: > Jan Labanowski, jkl/at/ccl.net (read about it on CCL Home Page) > -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+