Subject: summary: large ab initio calc's

From: Michael Braeuer <[email-masked]>
Date: Fri, 14 May 99 10:43:30 METDST

Hi,

Here comes the summary to my question about large ab initio calcs.
Thank you very much to all who replied.

Micha

Original question: I need to know the approximate size of the largest ab initio
calculations done with standard programs so far.

And here are the responses.

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Hi Micha,

dies haengt natuerlich entscheidend von dem ab, was Du rechnen
moechtest. Auf welchem Level und mit welchem Basissatz moechtest
Du denn rechnen? Auf MP2/6-31g** wuerde ich sagen ca. 50-60 Atome,
also single point! Und dies gilt fuer org. Molekuele ohne Metalle!

Viel Erfolg C.
--
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Christoph Schneider                       [email-masked]
Institute for Molecular Biotechnology
Beutenbergstrasse 11, -Biocomputing-      Tel.: +49-3641-65-6205
P.O. Box 100 813, D-07708 Jena, Germany   Fax:  +49-3641-65-6210
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Ich finde, das ist eine sehr unpraezise Frage!
"large" kann -meiner Meinung nach- naemlich folgendes bedeuten:
1. viele Atome (am wahrscheinlichsten)
2. viele Basisfunktionen (d.h. man kann kleine Molekuele mit grossen
Basissaetzen rechnen und grosse Molekuele werden eher mit kleinen
Basissaetzen gerechnet, wobei die >Zahl< der Funktionen gleich sein kann.
3. "large" im Sinne von viel Speicherplatz (Ram oder Festplatte). Dies kann
man sehr einfach durch correlierte Methoden (MP4, CCSD, usw.) "erreichen"

>Any hint where I could start searching ?

z.B.
A. Hishikawa, A. Iwamae, K. Hoshina, M. Kono, K. Yamanouchi     Mass-resolved
two-dimensional momentum imaging of the Coulomb explosion of N2 and SO2 in
an intense laser field  Chem. Phys. Lett.       282     (1998)  283

Gaussian Inc wirbt mit der Berechnung der Molekuels Taxol auf einem
Multiprozessorsystem fuer die Qualitaet des Parallel-codes (siehe
Dokumentation)

Gruesse
Wolfgang Roth
==W=R===========================W=o=l=f=g=a=n=g==R=o=t=h==
University of Leeds
School of Chemistry
Leeds LS2 9JT
UK
===== http://www-public.rz.uni-duesseldorf.de/~rothw =====

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Message 10/34 from Frank Jensen                     May 11 '99 at 12:14 (noon)

Return-Path: <[email-masked]>
Subject: Re: CCL:Large ab initio calculations

	check some of Gustavo Scuceria's lattest work,
	primarily in JCP.
		Frank

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In general I don't know how you'd go about finding such things, apart
>from careful and continuous reading of the literature.

I have recently done RI-MP2 calculations with 2460 AO basis functions
without taking advantage of symmetry using the NWChem parallel
computational chemistry code.  RI-MP2 is an approximate version of the
familiar MP2 correlated method.  It is surely among the largest
calculations done to date at this level, though I will not claim it is
_the_ largest.  If you want more information, I can send you pointers
on the RI-MP2 method and on the NWChem code; these particular
calculations are not quite written up yet.

I would be interested to know what other large calculations you learn
about.

Good luck, David
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David E. Bernholdt                      | Email:  [email-masked]
Northeast Parallel Architectures Center | Phone:  +1 315 443 3857
111 College Place, Syracuse University  | Fax:    +1 315 443 1973
Syracuse, NY 13244-4100                 | URL:    http://www.npac.syr.edu

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Hi Micha,

I'm not sure what you mean by standard, but we have carried out
RHF/STO-3G calculations with 2000 atoms and 6000 basis sets using
the serial version of MondoSCF.  I'm pretty sure this is the largest
to date.  See my page for info/papers.

With best regards, Matt

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you may want to look at a calculation on crambin, a protein containing 46
aminoacids (642 atoms).
JPC A, vol. 102, 2246-2251 (1998)
by Yu, Peeters, Martin, Sch\"afer and myself.

sincerely,

kris
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Kris Van Alsenoy,
Quantum Chemistry, Structural Chemistry Group, Department of Chemistry,
University of Antwerp (UIA), Universiteitsplein 1, B-2610 Antwerp, Belgium.
E-mail : [email-masked] / Phone : +32(3)8202366 / Fax : +32(3)8202310
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--
Michael Braeuer           http://www.uni-jena.de/chemie/anders/micha.htm
PhD Student               E-mail: [email-masked]
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