From chemistry-request -x- at -x- server.ccl.net Sun Dec 17 14:42:35 2000 Received: from Mercury.acs.unt.edu (mercury.acs.unt.edu [129.120.220.1]) by server.ccl.net (8.8.7/8.8.7) with ESMTP id OAA13513 for ; Sun, 17 Dec 2000 14:42:34 -0500 Received: from jove.acs.unt.edu (10759%!at!%jove.acs.unt.edu [129.120.220.41]) by Mercury.acs.unt.edu (8.8.8/8.8.8) with ESMTP id NAA13923 for ; Sun, 17 Dec 2000 13:42:31 -0600 (CST) Received: from localhost (tdp0006%!at!%localhost) by jove.acs.unt.edu (8.8.8/8.8.8) with ESMTP id NAA01265 for ; Sun, 17 Dec 2000 13:42:27 -0600 (CST) Date: Sun, 17 Dec 2000 13:42:26 -0600 (CST) From: TREVOR D POWER To: chemistry {*at*} ccl.net Subject: Re: CCL:Final structure in terms of initial Z-matrix Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Namazian, What version of Gaussian are you using? 94? Are you employing dummy atoms in the construction of you input file? I am not really sure what "Final structure in terms of initial Z-matrix" implies. If you specify a geometry in the input.file as a Z-matrix in either Gaussian 94 or Gaussian 98 without using opt=z-matrix the input geometry with be converted to redundant internal coordinates and the output parameters of the optimized geometry will not necessarily correspond to those in the input z-matrix. By default, Gaussian 92 interpreted opt (in the route card) as opt=z-matrix. You should note that opt=z-matrix is a very poor manner in which to obtain an optimized geometry because 1) the program will take forever to optimize the geometry based on just those parameters you specify in the input.file and 2) you have a very good chance of obtaining a local minumum as a result of inherent constrainst this technique employs. What I would do is specify opt=addredun (Gaussian 94) or opt=modredun (Gaussian 98) and at the end of the geometry input section of the input file explicity list those redundant coordinates you wish to see (in addition to those the program selects) in the output file. You will, of course, need to know what the approximate values are for these parameters so as to not perturb your initial geometry too much: 1 2 1.43 (for bond length) 1 2 3 120.0 (for angle) 1 2 3 4 34.0 (for dihedral angle) where 1, 2, 3 and 4 are atoms specified. If you use dummy atoms in the input, you cannot use these to construct these coordinates as dummy atoms are deleted once the geometry is read into the program and the molecule is transulated into redundant internal coordinates. You can get additional bond lengths from the distance matrix in the output.file. Also there is a way to print all angles and all dihedrals. If you are interested in that I can dig this up later. Hope this helped, David Power Department of Chemistry Univerity of North Texas NT Staion, Box 305070 Denton, Texas 76203-5070 tdp0006-: at :-unt.edu On Sat, 16 Dec 2000, Mansoor Namazian wrote: > Dear Sir, > > When I optimize a molecule using Gaussian, sometimes I get > the "Final structure in terms of initial Z-matrix:" at the > end of output file and sometimes I don't, no matter what > I specify in the route section. > I'd like to get always "Final structure in terms of initial > Z-matrix" at the end of output file. Can anyone help please? > > Many thanks in advance. > Namazian > > _________________________________________________________________________ > Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. > > > > -= This is automatically added to each message by mailing script =- > CHEMISTRY:~at~:ccl.net -- To Everybody | CHEMISTRY-REQUEST:~at~:ccl.net -- To Admins > MAILSERV _-at-_)ccl.net -- HELP CHEMISTRY or HELP SEARCH > CHEMISTRY-SEARCH-: at :-ccl.net -- archive search | Gopher: gopher.ccl.net 70 > Ftp: ftp.ccl.net | WWW: http://www.ccl.net/chemistry/ | Jan: jkl.,at,.ccl.net > > > > > >