From chemistry-request@server.ccl.net Mon Oct 8 05:04:58 2001 Received: from nikias.cc.uoa.gr ([195.134.68.10]) by server.ccl.net (8.11.6/8.11.0) with ESMTP id f9894vB23244 for ; Mon, 8 Oct 2001 05:04:58 -0400 Received: from localhost (jkerkin@localhost) by nikias.cc.uoa.gr (8.9.3/8.9.3) with SMTP id MAA04414; Mon, 8 Oct 2001 12:04:48 +0300 (EET DST) Date: Mon, 8 Oct 2001 12:04:48 +0300 (EET DST) From: John Kerkines To: Denny cc: "chemistry@ccl.net" Subject: Re: CCL:LaO, LaS and LaCL? In-Reply-To: <200110061315.f96DFSB08523@server.ccl.net> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Try the Huber and Herzberg compilation of diatomic molecules at http://webbook.nist.gov/chemistry/ Best Regards, Ioannis Kerkines On Sat, 6 Oct 2001, Denny wrote: > Hi everyone, > > I want to know the experimental values of equilibrium bond length, dissociation energy, spectroscopic contants of LaO, LaS > and LaCl compounds? Can anyone give me some hints where I can find except SCI search? Or Does anyone know if there is > e-print of preprint service of chemistry, just the same as physics: xxx.lanl.gov etc.? > > Thanks a lot! > > Denny Chen > > **************************** > * Denny Chen * > * Center for Astrophysics * > * Tsinghua University * > * Beijing, P.R.China * > * 8610-62792126(phone) * > * 8610-62792125(fax) * > **************************** > Email:dilys98@mails.tsinghua.edu.cn > > > > -= This is automatically added to each message by mailing script =- > CHEMISTRY@ccl.net -- To Everybody | CHEMISTRY-REQUEST@ccl.net -- To Admins > MAILSERV@ccl.net -- HELP CHEMISTRY or HELP SEARCH > CHEMISTRY-SEARCH@ccl.net -- archive search | Gopher: gopher.ccl.net 70 > Ftp: ftp.ccl.net | WWW: http://www.ccl.net/chemistry/ | Jan: jkl@ccl.net > > > > > > From chemistry-request@server.ccl.net Mon Oct 8 07:08:24 2001 Received: from yangtze.hku.hk (IDENT:root@[147.8.148.244]) by server.ccl.net (8.11.6/8.11.0) with ESMTP id f98B8NB29084 for ; Mon, 8 Oct 2001 07:08:23 -0400 Received: from localhost (andy@localhost) by yangtze.hku.hk (8.11.6/8.9.3) with ESMTP id f98BLKc25618 for ; Mon, 8 Oct 2001 19:21:20 +0800 Date: Mon, 8 Oct 2001 19:21:20 +0800 (HKT) From: Ng Man Fai To: Subject: B800 and B850 crystal structure Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Hi everyone, Does anyone know where the whole crystal structure of B800 BChla (8 rings) and B850 BChla (16 rings) of Rs. molischianum can be found? Thanks for every help. Best regards, Andy From chemistry-request@server.ccl.net Mon Oct 8 04:37:56 2001 Received: from orionl0.ccf.auth.gr ([155.207.199.31]) by server.ccl.net (8.11.6/8.11.0) with ESMTP id f988btB22158 for ; Mon, 8 Oct 2001 04:37:56 -0400 Received: from vanpc4 (vanpc4.chem.auth.gr [155.207.64.164]) by orionl0.ccf.auth.gr (8.11.6/8.11.4/8.11.4) with SMTP id f988brR13740 for ; Mon, 8 Oct 2001 11:37:54 +0300 (EET DST) Organization: Message-ID: <003a01c14fd4$78dfabb0$a440cf9b@chem.auth.gr> From: "Tasos V." To: Subject: CCL: Solvent effect problem Date: Mon, 8 Oct 2001 11:37:31 +0300 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0037_01C14FED.9D6DD970" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.50.4522.1200 Disposition-Notification-To: "Tasos V." X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4522.1200 This is a multi-part message in MIME format. ------=_NextPart_000_0037_01C14FED.9D6DD970 Content-Type: text/plain; charset="iso-8859-7" Content-Transfer-Encoding: quoted-printable Dear CCL'ers, I tried to run a calculation to estimate the HF energy value of a = Hydrogen aton in solution. The continuum models I used were: PCM, CPCM, IEFPCM and the Gaussian = version is 98W Revision A.7. The input file was as follows: ------------------------------------------------------------ # B3LYP/6-31+G(d) 5d SCRF(PCM, Solvent=3DWater) SCF=3DTight Test B3LYP/6-31+G(d) 5d SCRF=3DPCM H atom in water 0 2 H 0.000 0.000 0.000 78.39 ------------------------------------------------------------ G98w was unable to complete this calculation, the answer I got was: --------------------------- No nuclei in the second cavity Error termination via Lnk1e in G:\G98W\l502.exe. --------------------------- In an attempt to overcome this problem, I have also run a simple Onsager = model calculation, which, although afforded a HF energy value, = unfortunately, it yielded the same HF value for all different solvents = (n-Heptane, Acetonitrile, Water) I used. I would appreciate very much receiving your kind piece of advice. Thanking you in advance. Anastasios Vafiadis PhD candidate Aristotle University of Thessaloniki School of Chemistry Lab of Applied Quantum Chemistry P.O. Box 135 54-006 Thessaloniki Greece e-mail: vafiad@chem.auth.gr ------=_NextPart_000_0037_01C14FED.9D6DD970 Content-Type: text/html; charset="iso-8859-7" Content-Transfer-Encoding: quoted-printable
Dear CCL’ers,
 
I tried to run a calculation to estimate the HF energy value of a = Hydrogen=20 aton in solution.
The continuum models I used were: PCM, CPCM, IEFPCM and the = Gaussian=20 version is 98W Revision A.7.
The input file was as follows:
 
------------------------------------------------------------
# B3LYP/6-31+G(d) 5d SCRF(PCM, Solvent=3DWater) SCF=3DTight = Test
B3LYP/6-31+G(d) 5d SCRF=3DPCM H atom in water
0 2
H 0.000 0.000 0.000
78.39
------------------------------------------------------------
 
G98w was unable to complete this calculation, the answer I got = was:
 
---------------------------
No nuclei in the second cavity
Error termination via Lnk1e in G:\G98W\l502.exe.
---------------------------
 
In an attempt to overcome this problem, I have also = run a=20 simple Onsager model calculation, which, although afforded a HF energy = value,=20 unfortunately, it yielded the same HF value for all different solvents=20 (n-Heptane, Acetonitrile, Water) I used.
I would appreciate very much receiving your kind piece of = advice.
 
Thanking you in advance.
 
 
Anastasios Vafiadis
PhD candidate
Aristotle University of Thessaloniki
School of Chemistry
Lab of Applied Quantum Chemistry
P.O. Box 135
54-006 Thessaloniki
Greece
 
e-mail: vafiad@chem.auth.gr
------=_NextPart_000_0037_01C14FED.9D6DD970-- From chemistry-request@server.ccl.net Mon Oct 8 10:06:08 2001 Received: from ivory.trentu.ca ([192.75.12.103]) by server.ccl.net (8.11.6/8.11.0) with ESMTP id f98E68B00505 for ; Mon, 8 Oct 2001 10:06:08 -0400 Received: from trentu.ca ([204.225.12.60]) by trentu.ca (PMDF V5.2-32 #37862) with ESMTP id <01K9969OJK7E000FLO@trentu.ca> for chemistry@ccl.net; Mon, 8 Oct 2001 10:04:33 EDT Date: Mon, 08 Oct 2001 10:05:39 -0400 From: elewars Subject: charges on sphere, summary To: chemistry@ccl.net Message-id: <3BC1B2B2.16B8B3A6@trentu.ca> MIME-version: 1.0 X-Mailer: Mozilla 4.7 [en] (WinNT; I) Content-type: text/plain; charset=us-ascii Content-transfer-encoding: 7bit X-Accept-Language: en 2001 Oct 8 Hello, Here is the summary of replies I got to the question about the energy of a set of charges confined on/in a sphere. I thank all who responded, and hope I have not overlooked any reply. All the answers were intereresting and helpful. E. Lewars === The question: 2001 Oct 3 Hello, A colleague posed this question. Suppose you have two like point charges (e.g. two protons, considered dimensionless), which must be on or inside a sphere. The minimum energy geometry (MEG) is that they be on the surface, at the ends of a diameter of the sphere. For three charges, the MEG is on the surface, at the corners of an equilateral triangle. And so on for 4, 5, ...? charges, the MEG having all of them on the surface. Question: is there a number or numbers _n_ of charges for which migration of one or more charges _into_ the sphere would lower the energy? Is there some theorem in math or physics that deals with this? Thanks E. Lewars ============= #1 Prof. Lewars, I enjoy this type of problem. I know it is a theorem that there is no arrangement of (pos and neg) charges in space that is a local minimum. I suspect that the same is true of charges in an environment where there are some fixed charges about, which would mean that the charges in the interior can always move in some direction so as to lower the total energy. Then the MEG would have to have all charges on the surface. David Anick MD PhD David.Anick@gte.net Dear Prof. Lewars, Ignore previous response. The proof is easy. Suppose you have n point charges in fixed positions and you want to add the (n+1)st. Let F be the electric field generated by the original n. Then div(F) = 0 (Gauss's law). The divergence theorem says that the surface integral of Fn^ over a small bubble enclosing the new charge, equals the volume integral of div(F), which we know is zero. Make the bubble very small. Fn^ is positive in some direction(s) and negative in others. If the position of the new charge were a local min, F would point inward everywhere on the bubble, i.e. Fn^ would be negative on the entire bubble surface. This contradiction shows that there cannot be any local min for the energy as a function of the position of the new charge (with the other n positions fixed), except on the boundary. Once that charge moves to the boundary, the others may lower the energy further by moving around on the boundary, but that's not your question. NOTE: there can be saddle points for the potential energy in the interior, i.e. an interior charge might experience a force of zero, but they would be unstable stationary points. In the limit where there are thousands of charges spread out on the surface in a uniform distribution, as you know, the potential inside becomes constant. David Anick MD PhD David.Anick@gte,net ============== #2 Use the variational procedure to maximize the distance between points with the constraint that they lie on a sphere of radius R. The constraint is a lagrange multiplier and you simply work though the Ritz variational method. Alternatively, argue from simple geometry. In two dimensions, if you have a n-point polygon with all points on a circle of radius R, then the configuration which maximizes the distance (and hence minimizes the energy or cost function) between all points is a regular polygon. So, again, it's a result of the variational theorem. ERB -- Prof. Eric R. Bittner Department of Chemistry Univ. of Houston ph: 713-743-2775 fax: 713-743-2709 bittner@uh.edu http://k2.chem.uh.edu/bittner/ Actually, I didn't read your question carefully enough, but you could still use the variational method followed by classical perturbation theory to check this. But, geometry seems to argue that if you have n points distributed evenly over a sphere at the vertices of a regular polyhedron, the lowest energy configuration for the addition of one charge *inside* the sphere is at the center. The issue of whether perturbing one vertex of the polyhedron keeping the rest fixed is simple as well. From the point of view of the one charge being deflected, moving closer to any of the (n-1) charges must increase its potential energy. So the minimal energy configuration for the deflected charge is at r-> + infinity. This must be true for all n> 1. -- Prof. Eric R. Bittner Department of Chemistry Univ. of Houston ph: 713-743-2775 fax: 713-743-2709 bittner@uh.edu http://k2.chem.uh.edu/bittner/ ------------------------------------------------------------------------------------------- The sun, with all those planets revolving around it and dependent upon it, can still ripen a bunch of grapes as if it had nothing else in the universe to do. -Galileo Galilei, physicist and astronomer (1564-1642) ================= #3 Dear Prof. Lewars, I can't cite any theorems with respect to your colleague's question. However, since same-charge repulsion diminishes with the square of the distance, a good rule of thumb would be to make the smallest distance between charges as large as possible. This is related to the question of how many spheres of a given radius can be fitted into a sphere of unit- radius. The topic of densest packing might be a good starting point for searching the mathematical literature. Borane or metal clusters might also provide examples. Since the boundary conditions are different (no penetration of packed spheres vs. minimum repulsive energy), the packing problem is probably not the definitive answer but still a good starting point. >From a more practical point of view, I think that charges inside the sphere become competitive when the smallest distance d between charges on the surface of the sphere is smaller than the radius of the sphere. In a regular octahedron, d=sqrt(2)*r. In a cube, d=2r/sqrt(3). In a 4-sided antiprism the ratio d/r would be somewhat smaller (but still larger than 1, I believe). Therefore my guess is that with 8 charges one should be inside the sphere. The other 7 charges might be in an arrangement derived from a capped octahedron. Yours, Stefan Fau ______________________________________________________________________ Dr. Stefan Fau | fau@qtp.ufl.edu Quantum Theory Project | (352) 392-6714 University of Florida Gainesville, FL 32611-8435 =============== #4 Just a quick comment which I think shows that at some point you will want to put charge inside the sphere: if you consider a uniform charge density smeared over the sphere surface (approximating the situation where there are already many protons), the energy to add a new charge q on the surface comes out (in my hands) as 8 pi q sigma while the energy to put it at the center of the sphere is 4 pi q sigma, ie it is smaller. If you find a sophisticated exact result I'd be interested to hear about it... Cheers,simonson@schlitz.u-strasbg.fr Organization: CNRS Tom Simonson ========== #5 Dear Dr. Lewars ! If the charges are mobile within the sphere they will always accumulate on the surface - that's just Faraday's principle. If you have a charged piece of metal (i.e. "real life" equivalent of a system in which charges are freely mobile within a certain volume) any addiditonal charges will always accumulate on the surface (that's actually independent of the shape of the piece of metal. regards, egbert Egbert Zojer =================== ============= From chemistry-request@server.ccl.net Mon Oct 8 11:16:33 2001 Received: from mail.etang.com ([202.101.42.207]) by server.ccl.net (8.11.6/8.11.0) with ESMTP id f98FGWB05085 for ; Mon, 8 Oct 2001 11:16:32 -0400 Received: from lizhenhua (unknown [202.108.240.3]) by mail.etang.com (Postfix) with ESMTP id D5D611CB2DAC4 for ; Mon, 8 Oct 2001 23:17:29 +0800 (CST) Message-ID: <003d01c1500c$8bf1bdf0$de0a150a@lizhenhua> From: "Zhenhua Li" To: "CCL" Subject: exact energy of atoms or small poly-atoms Date: Mon, 8 Oct 2001 23:18:55 +0800 Organization: Chem. Dept. Fudan Univ. Shanghai, China MIME-Version: 1.0 Content-Type: text/plain; charset="gb2312" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2600.0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 Dear listers, Have you any idea how to find energies of exact or close to exact (either SCF or correlation level) one-particle basis set limit for atoms or small poly-atoms? Are there any exact energies of atoms or small poly-atoms (exact solution of Schrodinger equation)? Li Zhenhua From chemistry-request@server.ccl.net Mon Oct 8 23:57:12 2001 Received: from ce.fis.unam.mx ([132.248.33.1]) by server.ccl.net (8.11.6/8.11.0) with ESMTP id f993uKB27471 for ; Mon, 8 Oct 2001 23:56:32 -0400 Received: (from ramon@localhost) by ce.fis.unam.mx (8.9.3/8.9.3) id VAA09873 for chemistry@ccl.net; Mon, 8 Oct 2001 21:51:23 -0700 (PDT) From: Ramon Garduno Message-Id: <200110090451.VAA09873@ce.fis.unam.mx> Subject: Video Cards for Chemistry To: chemistry@ccl.net (CCL POST MSG) Date: Mon, 08 Oct 2001 21:51:22 PDT X-Mailer: Elm [revision: 212.2] Dear CCLers: This time I need a few words of advice from those of you working with PC's with either Windows or Linux OS and that have some OpenGL visualizers. I am about to purchase a video card that will allow me to see 3D pictures via stereo shutter glasses. In my quest I narrowed down my choices to: 1) ASUS 7700 NVidia GeForce2 GTS video card + 3D glasses, 2) ASUS V8200 GeForce3 64MB video card + 3D glasses, and 3) ELSA Gladiac Ultra GeForce2 64 MB + 3D Revelator glasses. In my readings I found out that ASUS boards have good cooling, and that ASUS shutter glasses are better than ELSA's. Nevertheless, my major concern is which one of these video cards will work best under OpenGL, and under Linux. I know that all of them seem to work well under Windows. I need an honest point of view, since I am planning to use the stereo options of HYPERCHEM, GOPENMOL, VMD and other visualizers. Looking forward to hearing from you, I thank you in advance. Cheers, Ramon Garduno -- "There are so many ways.... There is so little time...." "Hay tantos caminos..... Pero, hay tan poco tiempo....." ___________________________________________________________________________ Dr. Ramon Garduno-Juarez Research Professor in Biophysics CENTRO DE CIENCIAS FISICAS | EMAIL: ramon@ce.fis.unam.mx UNIVERSIDAD NAL. AUTONOMA DE MEXICO | Apdo. Postal 48-3 | VOICE: +52(5)6227749 ; +52(7)3291749 62251 Cuernavaca, Morelos | MEXICO | FAX: +52(5)6227775 & +52(7)3291775 ___________________________________EOF ____________________________________