BIG AB INITIO JOBS

["E. Lewars" <elewars(-(at)-)alchemy.chem.utoronto.ca>]

 1996 Feb 19
 Albeiro Restrepo asked about the biggest systems that have been studied by
 ab initio, and the reliability of the results. I don't claim that these are the
 biggest anyone has looked at, but they are at the high end of ab initio jobs:
 (1) MP2(FC)/6-311G** (312 basis funtions) on  C6H5-C:::C-C6H5: S. Saebo and
     J. Almlof et al, THEOCHEM 59, 361 (1989).
 (2) MP2/6-31G* optimizations on porphyrins, ca 20 heavy atoms. At the MP2 level,
     unlike the HF, the known, dampened bond alternation characteristic of these
     aromatic systems is evident. _Long_ calc's. See L. Paquette et al, ca. 1995
     (J Am Chem Soc?).
 (3) For a short, very useful review of work on ab initio etc calc's and their
     reliability, see I. N. Levine, _Quantum Chemistry_, 4th Ed., Prentice Hall,
     1991, Chapters 15, 16, 17.
   Errol Lewars