From owner-chemistry@ccl.net Wed Jan 24 04:59:01 2007
From: "Marcel Swart marcel.swart*icrea.es" <owner-chemistry::server.ccl.net>
To: CCL
Subject: CCL: ONIOM(B3LYP:UFF)=Embed
Message-Id: <-33430-070124042717-1459-KIZgy792kc6ArT6qtAI3HQ::server.ccl.net>
X-Original-From: Marcel Swart <marcel.swart[A]icrea.es>
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Date: Wed, 24 Jan 2007 10:27:00 +0100
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Sent to CCL by: Marcel Swart [marcel.swart++icrea.es]
UFF force field has no electrostatic interactions, therefore the  
charges should be zero.
So this seems correct to me.

See for instance: http://towhee.sourceforge.net/forcefields/uff.html

On Jan 23, 2007, at 11:56 PM, Tianxiao Yang xiaoyang_guelph(~) 
yahoo.com wrote:

>
> Sent to CCL by: "Tianxiao  Yang" [xiaoyang_guelph]-[yahoo.com]
> Dear Colleagues,
>
> I am suffering from the problem running ONIOM with electronic- 
> embedding. The output file shows that the Mulliken atomic charges  
> of Low Level atoms are zero.
>
> Here is a very simple input file:
>
> p ONIOM(TD B3LYP/6-31G(d):UFF)=Embed Geom=Connectivity
>
>  SP test H2O+H2O
>
> 0 1 0 1
>  O
>  H   1   0.96
>  H   1   0.96   2   109.5
>  O   3   3.239  1   54.278   2   0.0,0 L
>  H   4   0.96   3   141.96   1   0.0,0 L
>  H   4   0.96   3   108.54   1 180.0,0 L
>
>  1 2 1.0 3 1.0
>  2
>  3
>  4 5 1.0 6 1.0
>  5
>  6
>
> Part of the output file showing the Mulliken atomic charges of Low  
> Level zero.
>  Mulliken atomic charges:
>      1  O   -0.786748
>      2  H    0.393374
>      3  H    0.393374
>      4  O    0.000000
>      5  H    0.000000
>      6  H    0.000000
>
> Could you please tell me if I missed something in the input file?  
> Thanks a lot.
>
> Xiao Yang
> Department of Chemistry
> University of Guelph
>
>
>
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��������������������������������������������
dr. Marcel Swart

ICREA researcher at
Institut de Qu�mica Computacional
Universitat de Girona

Campus Montilivi
17071 Girona
Catalunya (Spain)

fax
+34-972-418356
e-mail
marcel.swart(~)icrea.es
marcel.swart(~)udg.es
web
http://www.icrea.es/pag.asp?id=Marcel.Swart
http://iqc.udg.es/~marcel
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From owner-chemistry@ccl.net Wed Jan 24 07:15:00 2007
From: "Wai-To Chan chan[*]curl.gkcl.yorku.ca" <owner-chemistry|*|server.ccl.net>
To: CCL
Subject: CCL: How do I compute the symmetry number in a TST calculation of a rate constant
Message-Id: <-33431-070124071328-3929-Vv8/lDI8lg6si7vU9T00wg|*|server.ccl.net>
X-Original-From: Wai-To Chan <chan__curl.gkcl.yorku.ca>
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Date: Wed, 24 Jan 2007 07:29:33 -0500 (EST)
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Sent to CCL by: Wai-To Chan [chan~!~curl.gkcl.yorku.ca]
<<<<<
I'm a little unclear on how the symmetry number is computed in a TST calculation 
of the rate constant. Can anyone recommend a clear discussion of this?
>>>>>>>>


	The second edition of Robinson and Holbrook's 'Unimolecular Reactions' 
explains how the statistical factor for rate constant calculation 
is evaluated in some details in section 3.9 (pg 56--59). 
I could be wrong but I can't see how the reaction symmetry number can be 
computed this way--it has to be done on paper. The easy way out for
computation is merely to account for the reaction
path degeneracy through inclusion of the rotational symmetry number 
in the rotation partition functions of the reactants and the transition
states in the TST expression. This approach according to the text could
result in errors. 

Wai-To Chan


From owner-chemistry@ccl.net Wed Jan 24 14:27:01 2007
From: "Rick Muller rpmuller[#]gmail.com" <owner-chemistry(-)server.ccl.net>
To: CCL
Subject: CCL: How do I compute the symmetry number in a TST calculation of a rate constant
Message-Id: <-33432-070124142538-31271-1gqW3Ig8vBDcKX5RS527Mg(-)server.ccl.net>
X-Original-From: "Rick Muller" <rpmuller::gmail.com>
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Date: Wed, 24 Jan 2007 12:25:29 -0700
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Sent to CCL by: "Rick Muller" [rpmuller**gmail.com]
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Thanks very much for all of the great responses.

On 1/24/07, Wai-To Chan chan[*]curl.gkcl.yorku.ca <owner-chemistry++ccl.net>
wrote:
>
>
> Sent to CCL by: Wai-To Chan [chan~!~curl.gkcl.yorku.ca]
> <<<<<
> I'm a little unclear on how the symmetry number is computed in a TST
> calculation
> of the rate constant. Can anyone recommend a clear discussion of this?
> >>>>>>>>
>
>
>         The second edition of Robinson and Holbrook's 'Unimolecular
> Reactions'
> explains how the statistical factor for rate constant calculation
> is evaluated in some details in section 3.9 (pg 56--59).
> I could be wrong but I can't see how the reaction symmetry number can be
> computed this way--it has to be done on paper. The easy way out for
> computation is merely to account for the reaction
> path degeneracy through inclusion of the rotational symmetry number
> in the rotation partition functions of the reactants and the transition
> states in the TST expression. This approach according to the text could
> result in errors.
>
> Wai-To Chan>
>
>
>


-- 
Rick Muller
rpmuller++gmail.com

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Thanks very much for all of the great responses.<br><br><div><span class="gmail_quote">On 1/24/07, <b class="gmail_sendername">Wai-To Chan chan[*]curl.gkcl.yorku.ca</b> &lt;<a href="mailto:owner-chemistry++ccl.net">owner-chemistry++ccl.net
</a>&gt; wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><br>Sent to CCL by: Wai-To Chan [chan~!~curl.gkcl.yorku.ca]<br>&lt;&lt;&lt;&lt;&lt;
<br>I&#39;m a little unclear on how the symmetry number is computed in a TST calculation<br>of the rate constant. Can anyone recommend a clear discussion of this?<br>&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;<br><br><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;The second edition of Robinson and Holbrook&#39;s &#39;Unimolecular Reactions&#39;
<br>explains how the statistical factor for rate constant calculation<br>is evaluated in some details in section 3.9 (pg 56--59).<br>I could be wrong but I can&#39;t see how the reaction symmetry number can be<br>computed this way--it has to be done on paper. The easy way out for
<br>computation is merely to account for the reaction<br>path degeneracy through inclusion of the rotational symmetry number<br>in the rotation partition functions of the reactants and the transition<br>states in the TST expression. This approach according to the text could
<br>result in errors.<br><br>Wai-To Chan<br><br><br><br<br<br<br<br><br>E-mail to subscribers: <a href="mailto:CHEMISTRY++ccl.net">CHEMISTRY++ccl.net</a> or use:<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="http://www.ccl.net/cgi-bin/ccl/send_ccl_message">http://www.ccl.net/cgi-bin/ccl/send_ccl_message
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</a><br><br>Subscribe/Unsubscribe:<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="http://www.ccl.net/chemistry/sub_unsub.shtml">http://www.ccl.net/chemistry/sub_unsub.shtml</a><br><br>Before posting, check wait time at: <a href="http://www.ccl.net">http://www.ccl.net
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</a><br><br>Search Messages: <a href="http://www.ccl.net/htdig">http://www.ccl.net/htdig</a>&nbsp;&nbsp;(login: ccl, Password: search)<br><br<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="http://www.ccl.net/spammers.txt"</a><br><br>RTFI: <a href="http://www.ccl.net/chemistry/aboutccl/instructions/">http://www.ccl.net/chemistry/aboutccl/instructions/</a><br><br<br><br><br><br></blockquote></div><br><br clear="all"><br>-- <br>Rick Muller<br><a href="mailto:rpmuller++gmail.com">rpmuller++gmail.com</a>

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