From chemistry-request@server.ccl.net Sun Oct 1 08:29:05 2000 Received: from panic.csc.cuhk.edu.hk (root@panic.csc.cuhk.edu.hk [137.189.6.35]) by server.ccl.net (8.8.7/8.8.7) with ESMTP id IAA26539 for ; Sun, 1 Oct 2000 08:29:03 -0400 Received: from l (dialup2-154.csc.cuhk.edu.hk [137.189.209.154]) by panic.csc.cuhk.edu.hk (8.9.3/8.9.3) with SMTP id UAA00477 for ; Sun, 1 Oct 2000 20:28:50 +0800 (HKT) Message-ID: <005e01c02ba3$3cd92020$27d3bd89@l> Reply-To: "Kiniu WONG Kin-Yiu" From: "Kiniu WONG Kin-Yiu" To: Subject: How to calculate excitation energy in high accuracy by Gaussian? Date: Sun, 1 Oct 2000 20:26:35 +0800 Organization: Physics CUHK MIME-Version: 1.0 Content-Type: text/plain; charset="big5" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.50.4133.2400 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4133.2400 Hi all, I couldn't get an accurate excitation energy by Gaussian, even a simple atom such as Hydrogen and Beryllium. The excitation energy of H is 10.2eV, but by UCIS(50-50)/6-31+G(d), it gives the excitation energy = 26.1eV: CIS wavefunction symmetry could not be determined. Excited State 1: ?Spin -?Sym 26.1001 eV 47.50 nm f=0.0000 1A -> 2A 1.00000 This state for optimization and/or second-order correction. Total Energy, E(Cis) = .460934644427 The excitation energy of Be is 2.7eV, but by UCIS(50-50)/6-31+G(d), the excitation energy = 1.69eV: CIS wavefunction symmetry could not be determined. Excited State 1: Triplet-?Sym 1.6892 eV 733.98 nm f=0.0000 2A -> 3A .47494 2A -> 5A .15415 2A -> 7A -.26459 2A -> 9A .40156 2B -> 3B -.47494 2B -> 5B -.15415 2B -> 7B .26459 2B -> 9B -.40156 This state for optimization and/or second-order correction. Total Energy, E(Cis) = -14.5076545141 What's wrong? Have I made some mistakes? Thanks for any help in advance! Regards, Kiniu ------ Kiniu WONG Kin-Yiu Undergraduate student Department of Physics The Chinese University of Hong Kong Email: kiniu@cuhk.edu.hk or kyiwong@phy.cuhk.edu.hk From chemistry-request@server.ccl.net Sun Oct 1 04:53:25 2000 Received: from mta4.263.net ([202.96.44.46]) by server.ccl.net (8.8.7/8.8.7) with ESMTP id EAA24926 for ; Sun, 1 Oct 2000 04:53:25 -0400 Received: by mta4.263.net (Postfix, from userid 60001) id 73DDC1C73407B; Sun, 1 Oct 2000 16:57:37 +0800 (CST) MIME-Version: 1.0 Message-Id: <39D6FC81.15535@mta4> Date: Sun, 1 Oct 2000 16:57:37 +0800 (CST) From: "张 科春" To: chemistry@ccl.net Subject: bsse procedure using Gaussian 98 X-Priority: 3 X-Originating-IP: [159.226.49.157] Dear cclers: Can you tell me if this process is coerrect?Sincerely need your help. Take it for example we use hf/6-31g* Basis Set Superposition Error (BSSE) Correct the dimerization energy for BSSE using the Counterpoise (CP) method. 1.Etot Dimer (opt. geom.) the energy from the hf/6-31g* optimized supramolecule 2.Etot 2*Monomer (opt. geom.) the energy from hf/6-31g* optimized monomer 3.EtotDonor (opt. geom. of dimer, with ghost basis at the acceptor) hf/6-31g* using Massage 4.Etot Acceptor (opt. geom. of dimer, with ghost basis at the donor) hf/6-31g* using Massage 5.Etot Donor (opt. geom. of dimer,without any ghost basis) 6.EtotAcceptor (opt. geom .of dimer, without any ghost basis) using hf /6-31g* to do single point calculation on the monomer with the deletion of other monomers in Suparmolecule BEuncorr = 1 - 2 BEcorr = BEuncorr - (3 - 5) - (4 - 6) _____________________________________________ 首都在线--中国人的网上家园 http://www.263.net @263.net中国最大的在线邮局 http://freemail.263.net 中国人的在线购物乐园——263商城 http://shopping.263.net 网上留学咨询-中国教育服务网 http://edu.263.net/ From chemistry-request@server.ccl.net Sun Oct 1 08:56:05 2000 Received: from panic.csc.cuhk.edu.hk (root@panic.csc.cuhk.edu.hk [137.189.6.35]) by server.ccl.net (8.8.7/8.8.7) with ESMTP id IAA26670 for ; Sun, 1 Oct 2000 08:56:03 -0400 Received: from l (dialup2-154.csc.cuhk.edu.hk [137.189.209.154]) by panic.csc.cuhk.edu.hk (8.9.3/8.9.3) with SMTP id UAA03042 for ; Sun, 1 Oct 2000 20:55:50 +0800 (HKT) Message-ID: <006b01c02ba7$02b93980$27d3bd89@l> Reply-To: "Kiniu WONG Kin-Yiu" From: "Kiniu WONG Kin-Yiu" To: Subject: How to compute LUMO eighen energy value by Gaussian or other programs in high accuracy? Date: Sun, 1 Oct 2000 20:56:26 +0800 Organization: Physics CUHK MIME-Version: 1.0 Content-Type: text/plain; charset="big5" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.50.4133.2400 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4133.2400 Dear all CCLers, By Gaussian, we could get HOMO energy and LUMO energy by just looking at the computed occupied eighen value and virtual unoccupied eighen value respectively. In order to get values in higher accuracy, we could equate HOMO to be E(cation) - E(neutral). Since HOMO energy means the minimum input energy to the system in order to remove an electron from the system. So during this process, the final state is just the cation of initial state. With this approach, I could get a much better HOMO when compared with the experimental value of the molecule (Alq3) in my project. However, on the other hand, it seems to be unreasonable to equate LUMO to be E(neutral) - E(anion). If LUMO = E(neutral) - E(anion), then it implies that LUMO energy means the minimum energy required to remove an electron from the anion (the initial state). In other words, if LUMO = E(neutral) - E(anion) then HOMO of anion = LUMO of neutral. We could imagine it's the energy of the system loss to attract a free electron to the NEUTRAL system. But, we also could imagine the HOMO-LUMO band gap in this way. Let E equals net energy required to remove an electron from the system to infinity then bring back this electron again to the system. However, this time the electron should not be in the initial orbit. So the minimum of E is equal to HOMO-LUMO band gap. If it's correct, LUMO is equal to the energy loss to attract a free electron to the CATION of the system in an orbit other than the initial one, such that E is the minimum. If it's right, then LUMO is not E(neutral) - E(anion). It also could explain why the computed LUMO energies are unreasonable in my project. So, my question is just that how to calculate LUMO accurately? Besides just looking at the given eighen values, could we compute higher accuracy of LUMO by Gaussian or other programs such as Jaguar? Thanks for any suggestions and helps!! Regards, Kiniu ------ Kiniu WONG Kin-Yiu Undergraduate student Department of Physics The Chinese University of Hong Kong Email: kiniu@cuhk.edu.hk or kyiwong@phy.cuhk.edu.hk From chemistry-request@server.ccl.net Sun Oct 1 09:24:02 2000 Received: from c012.sfo.cp.net (c012-h015.c012.sfo.cp.net [209.228.13.219]) by server.ccl.net (8.8.7/8.8.7) with SMTP id JAA26775 for ; Sun, 1 Oct 2000 09:24:01 -0400 Received: (cpmta 5638 invoked from network); 1 Oct 2000 06:21:50 -0700 Date: 1 Oct 2000 06:21:50 -0700 Message-ID: <20001001132150.5637.cpmta@c012.sfo.cp.net> X-Sent: 1 Oct 2000 13:21:50 GMT Received: from [194.249.5.41] by mail.altavista.com with HTTP; 01 Oct 2000 06:21:50 PDT Content-Type: text/plain Content-Disposition: inline Mime-Version: 1.0 To: chemistry@ccl.net From: Marina Ros X-Mailer: Web Mail 3.8.0.10 Subject: excluded volume Dear CCLers, I'm interested in calculating the excluded volume for the active site of an enzyme. Do you any program (free or not) for do that? Many thanks. Marina _______________________________________________________________________ Free Unlimited Internet Access! Try it now! http://www.zdnet.com/downloads/altavista/index.html _______________________________________________________________________ From chemistry-request@server.ccl.net Sun Oct 1 14:24:29 2000 Received: from mail-c.bcc.ac.uk (mail-c.bcc.ac.uk [144.82.100.23]) by server.ccl.net (8.8.7/8.8.7) with ESMTP id OAA28028 for ; Sun, 1 Oct 2000 14:24:28 -0400 Received: from socrates-a.ucl.ac.uk by mail-c.bcc.ac.uk with SMTP (Mailer); Sun, 1 Oct 2000 19:23:48 +0100 From: uccatvm Message-Id: <368.200010011824@socrates-a.ucl.ac.uk> Subject: Re: CCL:bsse procedure using Gaussian 98 To: chemistry@ccl.net (CCL) Date: Sun, 1 Oct 2000 19:24:27 +0100 (BST) In-Reply-To: <39D6FC81.15535@mta4> from " " at Oct 01, 2000 04:57:37 PM X-Mailer: ELM [version 2.5 PL3] MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit > Can you tell me if this process is coerrect?Sincerely need your hel= > p.=20 > Take it for example we use hf/6-31g*=20 > > Basis Set Superposition Error (BSSE)=20 > Correct the dimerization energy for BSSE using the Counterp= > oise (CP) method. =20 Your procedure is in principle correct; it is the correct way of computing the counterpoise-corrected interaction energy at a particular geometry. You have probably optimized the dimer geometry without counterpoise corrections, and in that case, this geometry may still be contaminated with BSSE (because the counterpoise-corrected and uncorrected potential energy surfaces will be shaped differently. How much, that depends on the particular molecular system you are investigating). In principle, you'd have to optimize the dimer geometry on the counterpoise-corrected potential energy surface (see for example S. Simon, M. Duran, J.J. Dannenberg, J. Chem. Phys. 105, 1996), but this is computationally more complicated, and more expensive as well. Hope this helps, Tanja -- ==================================================================== Tanja van Mourik phone University College London work: +44 (0)20-7679-4665 Christopher Ingold Laboratories home: +44 (0)1895-259-312 20 Gordon Street e-mail London WC1H 0AJ work: T.vanMourik@ucl.ac.uk United Kingdom home: tanja@netcomuk.co.uk ====================================================================