Ab Initio Calculations on Molecules containing Five or Six Atoms

Ab initio Calculations on Molecules containing Five or Six Atoms 

During the past five years there have been no spectacular advances in fundamental theory rather there has been a consolidation of earlier experience in ab initio methodology3 and a more widespread use of existing methods in tackling problems of interest to more chemists in general, i.e. there have been many more applications to medium sized polyatomic molecules, usually employing minimal basis sets (MBS). 

There have also been many more calculations in which geometry optimizations are carried out, and in which the basis sets in SCF calculations have been extended to DZ or DZ+P quality, and more recently one sees an increasing use of methods which include at least some electron correlation, especially via configuration interaction (Cl). Examples of the latter calculation were until recently restricted to molecules containing up to three atoms, but the recent development of efficient Cl programmes had enabled these calculations to be carried out without too great expense on a variety of larger molecules, and this work is referred to later on in this Report. 

In order that this Report be useful to non-specialists interested in earlier ab initio work in this area, it is useful to cite several reviews and books relevant to the subject matter of this chapter. The bibliography by Richards and co-workers4 has been 

Thomson, in Theoretical Chemistry , ed. R. N. Dixon and C. Thomson, (Specialist Periodical Reports), The Chemical Society, London, 1975, Vol. 2, p. 83. 

Thomson, in Theoretical Chemistry , ed. R. N. Dixon and C. Thomson, (Specialist Periodical Reports), The Chemical Society, London, 1975, Vol. 2, p. 83. s B. J. Duke, in Theoretical Chemistry , ed. R. N. Dixon and C. Thomson, (Specialist Periodical Reports), The Chemical Society, London, 1975, Vol. 2, p. 159. 

As in the previous Report, developments in theoretical and computational methods as such will not be dealt with. The results of calculations will usually be quoted in atomic units (distances/Bohr, energies/Hartree) but occasionally electron volts (eV) or kilojoules (kJ) for energies are used. A list of commonly used abbreviations is given at the beginning of this volume. 

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Ab initio Calculations on Molecules containing Five or Six Atoms Table 6 Computed energies and barriers to rotation for N204... 

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