From owner-chemistry@ccl.net Wed Oct  7 19:08:01 2015
From: "Fredrick Mutunga fredrick.mutunga++gmail.com" <owner-chemistry.:.server.ccl.net>
To: CCL
Subject: CCL: Potential energy surface with ZPEs appended
Message-Id: <-51805-151007190540-1959-t9NOwPpyeozKKpXPj1d3xQ.:.server.ccl.net>
X-Original-From: Fredrick Mutunga <fredrick.mutunga**gmail.com>
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Date: Wed, 7 Oct 2015 17:05:35 -0600
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Sent to CCL by: Fredrick Mutunga [fredrick.mutunga||gmail.com]
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Hello,

I have computed single point energies along the potential energy surface
using CCSD(T). I also have DFT calculated ZPEs for the stationary points
(this is an isomerization reaction cis-A ->trans-A) how do I append Zero
point energies to generate more accurate PES?

Thanks

--001a113ecd76baca0f05218bc86f
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<div dir="ltr"><div>Hello,<br></div><div><br>I have computed single point energies along the potential energy surface
 using CCSD(T). I also have DFT calculated ZPEs for the stationary points
 (this is an isomerization reaction cis-A -&gt;trans-A) how do I append 
Zero point energies to generate more accurate PES?<br><br></div>Thanks<br></div>

--001a113ecd76baca0f05218bc86f--


From owner-chemistry@ccl.net Wed Oct  7 20:40:01 2015
From: "=?iso-8859-1?Q?V=EDctor_Lua=F1a?= Cabal victor . fluor.quimica.uniovi.es" <owner-chemistry[a]server.ccl.net>
To: CCL
Subject: CCL: Potential energy surface with ZPEs appended
Message-Id: <-51806-151007203721-19367-3Gv7iPWagFOS4xQ0m0WzHQ[a]server.ccl.net>
X-Original-From: =?iso-8859-1?Q?V=EDctor_Lua=F1a?= Cabal <victor : fluor.quimica.uniovi.es>
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Date: Thu, 08 Oct 2015 02:18:11 +0200
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Sent to CCL by: =?iso-8859-1?Q?V=EDctor_Lua=F1a?= Cabal [victor*fluor.quimica.uniovi.es]
On Wed, Oct 07, 2015 at 05:05:35PM -0600, Fredrick Mutunga fredrick.mutunga++gmail.com wrote:
> I have computed single point energies along the potential energy surface
> using CCSD(T). I also have DFT calculated ZPEs for the stationary points
> (this is an isomerization reaction cis-A ->trans-A) how do I append Zero
> point energies to generate more accurate PES?

Frdederik,

Remember what the ZPE are. Check Wilson-Decius-Cross, Molecular
vibrations if you are in doubt.

As for a method you need the vibration energies of your molecule. Use
python or whatever script language you prefer. Is just enough.

For stationary points all your frequencies should be positive escept
the translations and rotation modes that you will identify quite close
to zero. For a transition state in your PES one more of the modes will
be the one corresponding to the reaction coordinate and the normal
constant will be negative, so the frequency clearly imaginary (except
that most electronic structure software does not use complex arithmetic
and it says negative frequencies).

Good luck,
          Dr. Víctor Luaña
--
     .  .    "In science a person can be convinced by a good argument.
    / `' \   That is almost impossible in politics or religion"
   /(o)(o)\  (Adapted from Carl Sagan)
  /`. \/ .'\  "Lo mediocre es peor que lo bueno, pero también es peor
 /   '`'`   \ que lo malo, porque la mediocridad no es un grado, es una
 |  \'`'`/  | actitud" -- Jorge Wasenberg, 2015
 |  |'`'`|  | (Mediocre is worse than good, but it is also worse than
  \/`'`'`'\/  bad, because mediocrity is not a grade, it is an attitude)
===(((==)))==================================+=========================
! Dr.Víctor Luaña, in silico chemist & prof. !"I have two kinds of problems,
! Departamento de Química Física y Analítica ! the urgent and the important.
! Universidad de Oviedo, 33006-Oviedo, Spain ! The urgent are not important,
! e-mail:   victor===fluor.quimica.uniovi.es   ! and the important are never
! phone: +34-985-103491  fax: +34-985-103125 ! urgent.
+--------------------------------------------+        (Dwight D. Eisenhower)
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