From chemistry-request -A_T- server.ccl.net Tue May 7 12:11:08 2002 Received: from hotmail.com ([64.4.37.220]) by server.ccl.net (8.11.6/8.11.0) with ESMTP id g47GB8V27153 for ; Tue, 7 May 2002 12:11:08 -0400 Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Tue, 7 May 2002 09:11:02 -0700 Received: from 171.64.127.133 by pv2fd.pav2.hotmail.msn.com with HTTP; Tue, 07 May 2002 16:11:02 GMT X-Originating-IP: [171.64.127.133] From: "Bin Shan" To: chemistry-: at :-ccl.net Subject: How to place a charge using CHARGE keyword in Gaussian98 Date: Tue, 07 May 2002 16:11:02 +0000 Mime-Version: 1.0 Content-Type: text/plain; format=flowed Message-ID: X-OriginalArrivalTime: 07 May 2002 16:11:02.0891 (UTC) FILETIME=[C8D4A3B0:01C1F5E1] I am trying to simulate the electric field by point charge and need to place the charge in an appropriate position relative to the molecule.I have difficulty trying to do this. # hf/6-31G(d) Charge Title section 0 1 molecule specification ... -10.000000 0.000000 17.320508 7.0 It is the last line that arises the difficulty.As my specification for the molecule is always in Z-matrix format,I do not know whether there is a convenient way to place the charge relative to my molecule(say,I want to it be 4.0A from atom1 and makes an angle 90 with atom1 and atom2 and a dihydral angle of 90 with atom1 and atom2 and atom3) > From Gaussian website: By default, the charges are read from the input stream, one per line, in this format: x y z charge point charge format So if I specify the molecule in Z-matrix format,I do not know how it is converted to cartesian coordinate and how the charge is placed relative to the molecule.If I were to use cartesian coordinate for the molecule,it is not very easy to specify the charge position relative to some certain atoms.I am wondering if there is a good way of doing that.Hope someone can help me out. _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp.