From chemistry-request #at# server.ccl.net Thu Nov 29 03:10:53 2001 Received: from mail2.zrz.tu-berlin.de ([130.149.4.14]) by server.ccl.net (8.11.6/8.11.0) with ESMTP id fAT8ArB05991 for ; Thu, 29 Nov 2001 03:10:53 -0500 Received: from mailszrz.zrz.tu-berlin.de ([130.149.4.11]) by mail2.zrz.tu-berlin.de with esmtp (exim-3.33) id 169MHG-0001PO-00; Thu, 29 Nov 2001 09:10:38 +0100 Received: from natrium.chem.tu-berlin.de ([130.149.169.143]) by mailszrz.zrz.tu-berlin.de with esmtp (exim-3.33) id 169MHG-0006Nr-00; Thu, 29 Nov 2001 09:10:38 +0100 Mime-Version: 1.0 X-Sender: chwu0531 -8 at 8- mailszrz.zrz.tu-berlin.de Message-Id: In-Reply-To: <200111281759.fASHxWV69116-: at :-mail.rpi.edu> References: <200111281759.fASHxWV69116 |-at-| mail.rpi.edu> Date: Thu, 29 Nov 2001 09:10:36 +0100 To: "Dr. N. SUKUMAR" From: Christoph van =?iso-8859-1?Q?W=FCllen?= Subject: Re: CCL:collation of responses on ab initio/first principles Cc: chemistry ":at:" ccl.net Content-Type: text/plain; charset="iso-8859-1" ; format="flowed" Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by server.ccl.net id fAT8ArB05992 > >Even the integrals need NOT be evaluated EXACTLY for a method to be called >ab initio. For instance, Gaussian employs several asymptotic and other >cutoffs to approximate integral evaluation. > This is only partly a valid argument. Are sin(x), cos(x), exp(x) etc. calculated "analytically" on any computer? They are computed with similar methods, so erf(x) or F0(x) (or a two-electron integral) is as analytical as any other transcendental function. +---------------------------------+----------------------------------+ | Prof. Christoph van Wüllen | Tele-Phone (+49) (0)30 314 27870 | | Technische Universität Sekr. C3 | Tele-Fax (+49) (0)30 314 23727 | | Straße des 17. Juni 135 | eMail | | D-10623 Berlin, Germany | Christoph.vanWullen(+ at +)TU-Berlin.De | +---------------------------------+----------------------------------+ --