From owner-chemistry@ccl.net Sat Aug  1 16:56:00 2015
From: "John Keller jwkeller%a%alaska.edu" <owner-chemistry%x%server.ccl.net>
To: CCL
Subject: CCL:G: Optimization preserving chiral centers in gaussian09
Message-Id: <-51558-150801161002-1276-XBT8h2NpYnYvnOzPtFlqxA%x%server.ccl.net>
X-Original-From: John Keller <jwkeller[-]alaska.edu>
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Date: Sat, 1 Aug 2015 12:09:56 -0800
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Sent to CCL by: John Keller [jwkeller ~ alaska.edu]
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Hi Mohan,
Try optimizing with a molecular mechanics method first, then MOPAC, then
your DFT method. MOPAC2012 is free and the multi-core version is extremely
fast.
John Keller


On Sat, Aug 1, 2015 at 8:33 AM, Mohan maruthi sena maruthi.sena]_[gmail.com
<owner-chemistry**ccl.net> wrote:

> Hi all,
>            I am trying to optimize a molecule containing 90 atoms and 4
> chiral centers in gaussian 09. I have tried with various methods like HF,
> DFT, MP2 and semi-emperical. I could not optimize the molecule and the
> error is convergence problem. In semi emperical method, the chiral centers
> are lost. Could give some suggestions to optimize such structure,
> preserving chiral centers in gaussian09.
>
>
> Thanks & Regards,
> Mohan
>

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<div dir=3D"ltr">Hi Mohan,<div>Try optimizing with a molecular mechanics me=
thod first, then MOPAC, then your DFT method. MOPAC2012 is free and the mul=
ti-core version is extremely fast.</div><div>John Keller</div><div><br></di=
v></div><div class=3D"gmail_extra"><br><div class=3D"gmail_quote">On Sat, A=
ug 1, 2015 at 8:33 AM, Mohan maruthi sena maruthi.sena]_[<a href=3D"http://=
gmail.com">gmail.com</a> <span dir=3D"ltr">&lt;<a href=3D"mailto:owner-chem=
istry**ccl.net" target=3D"_blank">owner-chemistry**ccl.net</a>&gt;</span> wro=
te:<br><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-=
left:1px #ccc solid;padding-left:1ex"><div dir=3D"ltr"><div><div><div>Hi al=
l, <br></div>=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 I=
 am trying to optimize a molecule containing 90 atoms and 4 chiral centers =
in gaussian 09. I have tried with various methods like HF, DFT, MP2 and sem=
i-emperical. I could not optimize the molecule and the error is convergence=
 problem. In semi emperical method, the chiral centers are lost. Could give=
 some suggestions to optimize such structure, preserving chiral centers in =
gaussian09.<br><br><br></div>Thanks &amp; Regards,<br></div>Mohan<br></div>
</blockquote></div><br></div>

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