From peon@medchem.dfh.dk Thu Oct 16 06:30:58 1997 Received: from danpost.uni-c.dk for peon@medchem.dfh.dk by www.ccl.net (8.8.3/950822.1) id GAA21661; Thu, 16 Oct 1997 06:30:09 -0400 (EDT) Received: from medchem.dfh.dk (medchem.dfh.dk [130.225.177.15]) by danpost.uni-c.dk (8.8.6/8.6) with SMTP id MAA26403; Thu, 16 Oct 1997 12:30:08 +0200 (METDST) Received: from [130.225.177.59] (compmac2 [130.225.177.59]) by medchem.dfh.dk (950413.SGI.8.6.12/950213.SGI.AUTOCF) via ESMTP id NAA01946; Thu, 16 Oct 1997 13:53:51 +0200 Message-Id: In-Reply-To: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Thu, 16 Oct 1997 12:30:11 +0200 To: Marc.Prosenc@uni-konstanz.de (Marc-Heinrich.Prosenc) From: Per-Ola Norrby Subject: Re: CCL:vibration spectras from force-field calculations Cc: CHEMISTRY@www.ccl.net Dear Marc, >it would be kind if anyone could tell me if there exist a program that >calculates >vibrational spectras from forcefields like MM2 or DISCOVER or HYPERCHEM >.... for free ? > >do there any public domain routines exist, which are able to refine >existing forcefields >like mm2 or amber when the IR-spectrum is given ? You should look up Tinker, from Jay Ponders lab. Check it out at: http://dasher.wustl.edu/tinker It's pretty hard to use IR spectra in the parameterization, and anyway, MM2 and AMBER aren't built to reproduce IR spectra. A few molecular mechanics force fields are, for example MM3 (available in Tinker) and CFF. In any case, I recommend parameterizing from a quantum chemical Hessian directly, not from the actual spectrum (a bit hard to do if what you have is the experimental spectrum :-). In most cases, it's almost hopeless to match normal modes between calculated and experimental spectrum, whereas the Hessian elements are well defined. Look up the work of Lifson & Warshel (CFF), Rasmussen (CFF-Lyngby), Hagler (CFF9x), Halgren (MMFF), ... Best Regards, Per-Ola Norrby ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ * Per-Ola Norrby, Associate Professor * The Royal Danish School of Pharmacy, Dept. of Med. Chem. * Universitetsparken 2, DK 2100 Copenhagen, Denmark * tel. +45-35376777-506, +45-35370850 fax +45-35372209 * Internet: peon@medchem.dfh.dk, http://compchem.dfh.dk/