From chemistry-request _-at-_)server.ccl.net Tue May 28 13:42:07 2002 Received: from mail.takas.lt ([212.59.31.78]) by server.ccl.net (8.11.6/8.11.0) with ESMTP id g4SHg6C22362 for ; Tue, 28 May 2002 13:42:07 -0400 Received: from olegas ([212.59.14.195]) by mail.takas.lt with Microsoft SMTPSVC(5.0.2195.2966); Tue, 28 May 2002 14:19:29 +0200 Message-ID: <000101c20642$a4a17c90$c30e3bd4: at :olegas> From: "Olegas Eicher-Lorka" To: Subject: G98W BSSE: SUMMARY Date: Tue, 28 May 2002 10:22:53 +0200 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_002E_01C20631.A03112D0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2600.0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 X-OriginalArrivalTime: 28 May 2002 12:19:29.0639 (UTC) FILETIME=[EA7B5F70:01C20641] This is a multi-part message in MIME format. ------=_NextPart_000_002E_01C20631.A03112D0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Dear CCLers, Many thanks for all of the replies for our orginal question: In the "standard" BSSE equation (for a dimer AB): =20 BSSE(AB) =3D E(AB)^AB - E(A)^A - E(B)^B + [E(A')^A - E(A')^AB + E(B)^B - = E(B)^AB] =20 I've got most of the parameters, but how in G98W do I calculate E(A)^AB = and E(B)^AB, i.e. the energy of the monomer units in terms of the dimer = basis set. Sam Abrash wrote: "You replace the other molecule's atoms with ghost atoms that are still = assigned the basis functions of the other molecule and then you do the = calculation. It's the counterpoise method." I actually did this originally, but I obtained "strange" results, which = I thought meant that I had done something wrong. It turns out that the keyword to use is MASSAGE: Wolfgang Roth wrote: "to calculate E(A)^AB and E(B)^AB usually the atomic charge of the non intesting atoms , e.g. B resp. B, is set to zero. Thus, the basic = functions of these atoms are still present. In Gaussian, the massage keyword is = used" But many thanks go to Tanja van Mourik who gave me an excellent = reference list: "With Gaussian, the keyword Massage has to be used for counterpoise=20 corrections (assuming it's the same for G98 and G98W). Have a look at = the=20 Gaussian manual: http://www.gaussian.com/00000452.htm. There is an example there as well. However, don't believe the sentence about counterpoise being only a crude estimate, have a look at the=20 following papers to learn more about BSSE and Counterpoise: - F.B. van Duijneveldt, J.G.C.M. van Duijneveldt-van de Rijdt, and J.H. van Lenthe, Chem. Rev. 94, 1873, 1994 (on counterpoise theory) - S. Simon, M. Duran, J.J. Dannenberg, J. Chem. Phys. 105, 1996 (on geometry optimizations on BSSE-corrected potential energy = surfaces). - F.B. van Duijneveldt, "Basis Superposition Error" in "Molecular Interactions" S. Scheiner (ed.), Wiley (1997) - T. van Mourik, A.K. Wilson, K.A. Peterson, D.E. Woon, T.H. Dunning, = Jr., Adv. Quant. Chem. 31, 105, 1999 (showing BSSE effects on interaction energies, distances, and frequencies)." Ta very much Tanja! Olegas ------=_NextPart_000_002E_01C20631.A03112D0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Dear CCLers,

Many thanks for all of the replies = for our=20 orginal question:

In the "standard" BSSE equation (for a = dimer=20 AB):

BSSE(AB) =3D E(AB)^AB - E(A)^A - E(B)^B + [E(A')^A - = E(A')^AB +=20 E(B)^B - E(B)^AB]

I've got most of the parameters, but how = in G98W=20 do I calculate E(A)^AB and E(B)^AB, i.e. the energy of the monomer units = in=20 terms of the dimer basis set.

Sam Abrash wrote:

"You replace=20 the other molecule's atoms with ghost atoms that are still assigned the = basis=20 functions of the other molecule and then you do the calculation. = It's the=20 counterpoise method."

I actually did this originally, but I = obtained=20 "strange" results, which I thought meant that I had done something=20 wrong.

It turns out that the keyword to use is = MASSAGE:

Wolfgang Roth wrote:

"to calculate=20 E(A)^AB and E(B)^AB usually the atomic charge of the non
intesting = atoms ,=20 e.g. B resp. B, is set to zero. Thus, the basic functions
of these = atoms are=20 still present. In Gaussian, the massage keyword is = used"

But many thanks go to Tanja van Mourik = who gave me=20 an excellent reference list:

"With Gaussian,=20 the keyword Massage has to be used for counterpoise
corrections = (assuming=20 it's the same for G98 and G98W). Have a look at the
Gaussian = manual:=20 http://www.gaussian.com/00000452.htm.
There is an example there as = well. However,=20 don't believe the sentence
about counterpoise being only a crude = estimate,=20 have a look at the
following papers to learn more about BSSE and=20 Counterpoise:

- F.B. van Duijneveldt, J.G.C.M. van = Duijneveldt-van=20 de Rijdt, and
   J.H. van Lenthe, Chem. Rev. 94, 1873, 1994 = (on=20 counterpoise theory)

- S. Simon, M. Duran, J.J. Dannenberg, = J.=20 Chem. Phys. 105, 1996
   (on geometry optimizations on=20 BSSE-corrected potential energy surfaces).

- F.B. van = Duijneveldt,=20 "Basis Superposition Error"
   in "Molecular Interactions" = S.=20 Scheiner (ed.), Wiley (1997)

- T. van Mourik, A.K. Wilson, = K.A.=20 Peterson, D.E. Woon, T.H. Dunning, Jr.,
   Adv. Quant. = Chem. 31,=20 105, 1999 (showing BSSE effects on interaction
   energies, = distances, and frequencies)."

Ta very much Tanja!

Olegas

------=_NextPart_000_002E_01C20631.A03112D0--