From chemistry-request;at;ccl.net Mon Jun 27 14:02:12 2005 Received: from smtpgw.sud-chemieinc.com (smtpgw.sud-chemieinc.com [208.23.162.5]) by server.ccl.net (8.13.1/8.13.1) with ESMTP id j5RI2Bk3024756 for >ccl.net>; Mon, 27 Jun 2005 14:02:11 -0400 Received: from localhost (localhost.localdomain [127.0.0.1]) by localhost.sud-chemieinc.com (Postfix) with ESMTP id 8D3A1324078 for >ccl.net>; Mon, 27 Jun 2005 13:47:23 -0400 (EDT) Received: from smtpgw.sud-chemieinc.com ([127.0.0.1]) by localhost (smtpgw.sud-chemieinc.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 32050-05 for >ccl.net>; Mon, 27 Jun 2005 13:47:20 -0400 (EDT) Received: from srvkyec1.americas.sc-world.com (srvkyec1.americas.sc-world.com [10.16.100.11]) by smtpgw.sud-chemieinc.com (Postfix) with ESMTP id EA0AF3240D5 for >ccl.net>; Mon, 27 Jun 2005 13:47:19 -0400 (EDT) Received: from srvkyem1.americas.sc-world.com ([10.16.100.68]) by srvkyec1.americas.sc-world.com with Microsoft SMTPSVC(5.0.2195.6713); Mon, 27 Jun 2005 14:01:29 -0400 content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01C57B42.3DFAEB96" X-MimeOLE: Produced By Microsoft Exchange V6.0.6556.0 Subject: RE: Modeling a chemical reactivity Date: Mon, 27 Jun 2005 14:01:28 -0400 Message-ID: <9DD56492790889439F731F5BD6DACA0007D78B2A<>srvkyem1.americas.sc-world.com> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: Modeling a chemical reactivity Thread-Index: AcV4Jhz8gmByPPG3SqKLJ1lzL5swpwDGs2zw From: "Shobe, David" >sud-chemieinc.com> To: >ccl.net> X-OriginalArrivalTime: 27 Jun 2005 18:01:29.0820 (UTC) FILETIME=[3E9901C0:01C57B42] X-Spam-Status: No, score=0.0 required=5.0 tests=HTML_60_70,HTML_MESSAGE autolearn=failed version=3.0.4 X-Spam-Checker-Version: SpamAssassin 3.0.4 (2005-06-05) on server.ccl.net This is a multi-part message in MIME format. ------_=_NextPart_001_01C57B42.3DFAEB96 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable One thing I would add to Phil's reply is that there is often a "van der = Waals" minimum for A + B (the molecules are "next to" one another but = have not reacted), and that the optimized geometry of this complex can = be used in the QST2 or QST3 method. Finding the TS is still tricky = though. :-) =20 Occasionally a bimolecular reaction will NOT have a transition state, = but the energy is downhill monotonic from infinitely separated reactants = to products. Generally this will only happen when bonds are formed = without other bonds having to break. =20 --David Shobe, Ph.D., M.L.S.=20 S=FCd-Chemie, Inc.=20 phone (502) 634-7409=20 fax (502) 634-7724=20 Don't bother flaming me: I'm behind a firewall.=20 _____ =20 From: Computational Chemistry List [mailto:chemistry-request<>ccl.net] On = Behalf Of may abdelghani Sent: Thursday, June 23, 2005 6:18 AM To: chemistry<>ccl.net Subject: CCL:Modeling a chemical reactivity Hello, CCLers = =20 Can, some body tell me how I can model this reaction: A+ B \\\\.>C (not, = A\\\\\ >B, I know how I do), with computational chemistry software, like = spartan, hyperchem, G98/03 ext Best regards _____ =20 Appel audio GRATUIT partout dans le monde avec le nouveau Yahoo! = Messenger Tilichargez le ici ! = =20 ------_=_NextPart_001_01C57B42.3DFAEB96 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

One thing I would add to Phil's reply is that = there is=20 often a "van der Waals" minimum for A + B (the molecules are "next to" = one=20 another but have not reacted), and that the optimized geometry of this = complex=20 can be used in the QST2 or QST3 method. Finding the TS is still = tricky=20 though. :-)

Occasionally a bimolecular reaction will NOT have a transition = state, but=20 the energy is downhill monotonic from infinitely separated reactants to=20 products. Generally this will only happen when bonds are formed = without=20 other bonds having to break.

--David Shobe, Ph.D., M.L.S. =
S=FCd-Chemie, Inc.
phone=20 (502) 634-7409
fax (502) = 634-7724

Don't bother flaming me: I'm behind a=20 firewall.

From: Computational Chemistry List=20 [mailto:chemistry-request<>ccl.net] On Behalf Of may=20 abdelghani
Sent: Thursday, June 23, 2005 6:18 AM
To: = chemistry<>ccl.net
Subject: CCL:Modeling a chemical=20 reactivity

Hello, CCLers

Can, some body tell me how I can model this = reaction: A+=20 B \\\\.>C=20 (not, A\\\\\ >B, I know how I do), with computational chemistry = software,=20 like spartan, hyperchem, G98/03 = ext

Best=20 regards

Appel audio GRATUIT partout dans le = monde avec=20 le nouveau Yahoo! Messenger
Tilichargez=20 le ici ! ------_=_NextPart_001_01C57B42.3DFAEB96--