From owner-chemistry@ccl.net Wed Dec 16 01:10:01 2015
From: "Aniruddha Ganguly ani.physichem-x-gmail.com" <owner-chemistry^^server.ccl.net>
To: CCL
Subject: CCL:G: how to freeze in gaussian
Message-Id: <-51922-151216010853-25317-7b8yjITgBp86y41Sn+EZEw^^server.ccl.net>
X-Original-From: Aniruddha Ganguly <ani.physichem(-)gmail.com>
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Date: Wed, 16 Dec 2015 11:38:47 +0530
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Sent to CCL by: Aniruddha Ganguly [ani.physichem|a|gmail.com]
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If you are trying to freeze a bond length, the simplest option would be to
use the letter "F" after the particular bond length in the variable
portion, say for example

b4= x.xxx F

Thus, that particular length will freeze during the calculation.

But, in that case you will have to change the "Opt" keyword with "Popt"
(partial optimization).

I hope it helps.

Regards,
Aniruddha

*Aniruddha Ganguly*

*c/o Prof. Nikhil Guchhait*
*Senior Research Fellow*
*Department of Chemistry*
*University of Calcutta*
*92, A.P.C. Road*
*Kolkata-700009*

On Wed, Dec 16, 2015 at 5:15 AM, Sofia Vasilakaki svasilak(-)chem.uoa.gr <
owner-chemistry=ccl.net> wrote:

>
> Sent to CCL by: "Sofia Vasilakaki" [svasilak%a%chem.uoa.gr]
> Hi,
>
> There are a few things you might want to try. Usually 'nosymm' keyword
> will keep the atoms fixed during opt. 'modredundant' usually works for me.
> There are some examples here http://www.gaussian.com/g_tech/g_ur/k_opt.htm
> (scroll down) in case you haven't seen them.
>
> Here http://www.ccl.net/chemistry/resources/messages/2004/06/02.007-dir/
> is an older thread.
>
>
> Cheers,
> Sofia V.
>
>
>
> >
> > Sent to CCL by: "kiran  k" [kd2f..mtmail.mtsu.edu]
> > Dear CCLusers,
> >
> > Could anyone suggest how to find interaction energy between formaldehyde
> > and
> > fluoride ion in gaussian using z-matrix, by keeping the distance
> constant.
> > After the calculation, the distance changed. Here is my example input
> look
> > like
> >  ----------------------------------------------------------------------
> > #P B3LYP/6-31+G* opt Test
> >
> > Geometry Optimization
> >
> > -1 1
> > C
> > O  1  r2
> > F  1  r3  2  a3
> > H  1  r4  2  a4  3  d4
> > H  1  r5  2  a5  3  d5
> > Variables:
> > r2= 1.2246
> > a3=  90.00
> > r4= 1.1017
> > a4= 122.24
> > d4= 354.18
> > r5= 1.1017
> > a5= 122.24
> > d5= 174.18
> > constant:
> > r3= 2.5000
> >
> > Thank you in advance>
>
>

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<div dir=3D"ltr">If you are trying to freeze a bond length, the simplest op=
tion would be to use the letter &quot;F&quot; after the particular bond len=
gth in the variable portion, say for example<div><br></div><div>b4=3D x.xxx=
 F</div><div><br></div><div>Thus, that particular length will freeze during=
 the calculation.</div><div><br></div><div>But, in that case you will have =
to change the &quot;Opt&quot; keyword with &quot;Popt&quot; (partial optimi=
zation).</div><div><br></div><div>I hope it helps.</div><div><br></div><div=
>Regards,</div><div>Aniruddha</div></div><div class=3D"gmail_extra"><br cle=
ar=3D"all"><div><div class=3D"gmail_signature"><div dir=3D"ltr"><div><div d=
ir=3D"ltr"><font face=3D"comic sans ms, sans-serif"><b>Aniruddha Ganguly</b=
></font><div><font face=3D"comic sans ms, sans-serif"><b>c/o Prof. Nikhil G=
uchhait<br></b></font><div><font face=3D"comic sans ms, sans-serif"><b>Seni=
or Research Fellow</b></font></div><div><font face=3D"comic sans ms, sans-s=
erif"><b>Department of Chemistry</b></font></div><div><font face=3D"comic s=
ans ms, sans-serif"><b>University of Calcutta</b></font></div><div><font fa=
ce=3D"comic sans ms, sans-serif"><b>92, A.P.C. Road</b></font></div><div><f=
ont face=3D"comic sans ms, sans-serif"><b>Kolkata-700009</b></font></div></=
div></div></div></div></div></div>
<br><div class=3D"gmail_quote">On Wed, Dec 16, 2015 at 5:15 AM, Sofia Vasil=
akaki svasilak(-)<a href=3D"http://chem.uoa.gr">chem.uoa.gr</a> <span dir=
=3D"ltr">&lt;<a href=3D"mailto:owner-chemistry=ccl.net" target=3D"_blank">o=
wner-chemistry=ccl.net</a>&gt;</span> wrote:<br><blockquote class=3D"gmail_=
quote" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1=
ex"><br>
Sent to CCL by: &quot;Sofia Vasilakaki&quot; [svasilak%a%<a href=3D"http://=
chem.uoa.gr" rel=3D"noreferrer" target=3D"_blank">chem.uoa.gr</a>]<br>
Hi,<br>
<br>
There are a few things you might want to try. Usually &#39;nosymm&#39; keyw=
ord<br>
will keep the atoms fixed during opt. &#39;modredundant&#39; usually works =
for me.<br>
There are some examples here <a href=3D"http://www.gaussian.com/g_tech/g_ur=
/k_opt.htm" rel=3D"noreferrer" target=3D"_blank">http://www.gaussian.com/g_=
tech/g_ur/k_opt.htm</a><br>
(scroll down) in case you haven&#39;t seen them.<br>
<br>
Here <a href=3D"http://www.ccl.net/chemistry/resources/messages/2004/06/02.=
007-dir/" rel=3D"noreferrer" target=3D"_blank">http://www.ccl.net/chemistry=
/resources/messages/2004/06/02.007-dir/</a><br>
is an older thread.<br>
<br>
<br>
Cheers,<br>
Sofia V.<br>
<div><div class=3D"h5"><br>
<br>
<br>
&gt;<br>
&gt; Sent to CCL by: &quot;kiran=C2=A0 k&quot; [kd2f..<a href=3D"http://mtm=
ail.mtsu.edu" rel=3D"noreferrer" target=3D"_blank">mtmail.mtsu.edu</a>]<br>
&gt; Dear CCLusers,<br>
&gt;<br>
&gt; Could anyone suggest how to find interaction energy between formaldehy=
de<br>
&gt; and<br>
&gt; fluoride ion in gaussian using z-matrix, by keeping the distance const=
ant.<br>
&gt; After the calculation, the distance changed. Here is my example input =
look<br>
&gt; like<br>
&gt;=C2=A0 ----------------------------------------------------------------=
------<br>
&gt; #P B3LYP/6-31+G* opt Test<br>
&gt;<br>
&gt; Geometry Optimization<br>
&gt;<br>
&gt; -1 1<br>
&gt; C<br>
&gt; O=C2=A0 1=C2=A0 r2<br>
&gt; F=C2=A0 1=C2=A0 r3=C2=A0 2=C2=A0 a3<br>
&gt; H=C2=A0 1=C2=A0 r4=C2=A0 2=C2=A0 a4=C2=A0 3=C2=A0 d4<br>
&gt; H=C2=A0 1=C2=A0 r5=C2=A0 2=C2=A0 a5=C2=A0 3=C2=A0 d5<br>
&gt; Variables:<br>
&gt; r2=3D 1.2246<br>
&gt; a3=3D=C2=A0 90.00<br>
&gt; r4=3D 1.1017<br>
&gt; a4=3D 122.24<br>
&gt; d4=3D 354.18<br>
&gt; r5=3D 1.1017<br>
&gt; a5=3D 122.24<br>
&gt; d5=3D 174.18<br>
&gt; constant:<br>
&gt; r3=3D 2.5000<br>
&gt;<br>
&gt; Thank you in advance&gt;<br>
&gt;<br>
&gt;<br>
<br>
<br>
<br>
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