From chemistry-request@ccl.net Sat May 31 11:20:47 2003 Received: from web10409.mail.yahoo.com (web10409.mail.yahoo.com [216.136.128.122]) by server.ccl.net (8.12.8/8.12.8) with SMTP id h4VFKlgC018203 for ; Sat, 31 May 2003 11:20:47 -0400 Message-ID: <20030531152046.34245.qmail~at~web10409.mail.yahoo.com> Received: from [172.167.50.162] by web10409.mail.yahoo.com via HTTP; Sat, 31 May 2003 08:20:46 PDT Date: Sat, 31 May 2003 08:20:46 -0700 (PDT) From: Guosheng Wu Subject: Molecular Orbital, QM and beyond (only to those interested) To: chemistry~at~ccl.net MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Since it's in the weekend time for most people around the world, just add a few spices into this "barbecue", without any attempt to challenge anyone else's opinions, and hope everyone who has no any interest in the subject would not have wasted time in reading my emails. (1)The foundation of modern science is mostly composed of the abilities of human being on imagination & creativity, mathematics & observations(physical experiments mainly beginning from Galilee). Imagination & creativity is the unique(?) property of human being; mathematics & observation are the tools for our brain and hands to explore the landscape of the physical world. Any comments on scientifical topics should consider this first. The above sentense also fits the discussion of "molecular orbital". As claimed for many times in this list by many people, molecular orbital or wave function in any sense is not observation, but a mathematical tool. A Simple "veto" to anyone who is still questioning that is: there are real numbers/functions(0,1,-1, pai,e,...) and the complex numbers/functions(i, cos(theta)+i*sin(theta),...) and i is the simplest complex number/function, purely imaginative, so it's not in the scope of an observation, but can be only "observated" in the brain of human. Molecular orbital or wave functions have lots to do with the "i", so... (2)The landscape of our knowledge in science is evolving in a speed beyond the imagination of many people. A simple example is that there was some report on the possibility that a male person may be able to give new birth without any information from a female person, but himself or another man. In some sense this would lead to challenge in various areas, including science, even the practice of such kind of thing will take a while to become feasible. Similarly for the laws on the motions of matter: QM is the current best description, and to my knowledge, it has no conflicts with all of the current experimental observations. If one day new experimental data might find the conflicts, it will be time for a broader theory than the current QM, and this has nothing to do with the truth that "i" is imaginative, not real. (3)Philosophy is good, and it is difficult. This may be beyond the ability or interest to most of the audience in this list, and may attach someone to the scope of religion. (For example, "belif" means "existance"?) Anyway, it's nice to see different views to one of the most useful concept in quantum chemistry, and it's at least good for me to practice English. Cheers. Guosheng Wu (currently a contractor to a pharmaceutical company, to a foreign country and to life; all in the sense of time/dynamics; hopefully people in the pharmaceutical industry sooner or later will help change the dynamics of life significantly, then the contract can extend a little bit for everyone... ) __________________________________ Do you Yahoo!? Yahoo! Calendar - Free online calendar with sync to Outlook(TM). http://calendar.yahoo.com From chemistry-request@ccl.net Sat May 31 08:25:10 2003 Received: from mail-b.bcc.ac.uk (mail-b.bcc.ac.uk [144.82.100.22]) by server.ccl.net (8.12.8/8.12.8) with ESMTP id h4VCP9gC015268 for ; Sat, 31 May 2003 08:25:09 -0400 Received: from socrates-a.ucl.ac.uk by mail-b.bcc.ac.uk with SMTP (Mailer) with ESMTP; Sat, 31 May 2003 13:24:58 +0100 Received: (from uccatvm@localhost) by socrates-a.ucl.ac.uk (8.11.7+Sun/8.9.3) id h4VCOvG18404; Sat, 31 May 2003 13:24:57 +0100 (BST) Message-Id: <200305311224.h4VCOvG18404~at~socrates-a.ucl.ac.uk> Subject: CCL: charge densities To: chemistry~at~ccl.net (CCL) Date: Sat, 31 May 2003 13:24:57 +0100 (BST) Cc: T.vanMourik~at~ucl.ac.uk (Tanja van Mourik) From: Tanja van Mourik X-Mailer: ELM [version 2.5 PL3] MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Hi CCL'ers, I would like to compute highly accurate charge densities for atoms. Gaussian can calculate densities (for population and other analysis procedures), but if I understand the manual correctly, this can only be done for MP2, MP3, MP4(SDQ), QCISD, CCD, CCSD, CID and CISD and SAC-CI methods. I would like to have densities for methods that include triple excitations, like CCSD(T). As far as I am aware, Molpro and NWChem also do not calculate densities for highly correlated methods. Is there a theoretical reason why these programs do not compute densities for, say, CCSD(T) or CCSDT? Would it be at all possible? And if so, does anybody know a program that can compute charge densities for highly correlated methods? Thanks a lot, Tanja -- ===================================================================== Tanja van Mourik Royal Society University Research Fellow Chemistry Department University College London phone: +44 (0)20-7679-4663 20 Gordon Street e-mail: work: T.vanMourik~at~ucl.ac.uk London WC1H 0AJ, UK home: tanja_van_mourik~at~btopenworld.com http://www.chem.ucl.ac.uk/people/vanmourik/index.html =====================================================================