Gaussian series of programs

In general the reported calculations used standard ab initio methods as implemented in the Gaussian series of programs. Details can be found in [4] and in our papers quoted in the text. 

Presently the most complete PCM implementation is available in the Gaussian series of programs [68] (Gaussian98 and the development version, Gaussian99, which will be distributed in the next future), allowing for ... 

Except as otherwise specified, all the results described in this subsection have been obtained by ab initio SCF calculations, at the 4-31G level. The geometry of each species has been fully optimized using the gradient techniques of the Gaussian series of programs (Binkley et al., 1981). 

SCF-type (see section 6.1) SE theories are based to a large extent on the approximate MO theory (see the book of this title [10]) developed by Pople and coworkers. The Pople school, however, went on to concentrate on the development of ab initio methods, and indeed it is for his contributions to these, which are largely encapsulated in the Gaussian series of programs [21], that Pople was awarded the 1998 Nobel Prize in chemistry [22] (shared with Walter Kohn, a pioneer in density functional theory see... 

Quantum chemists have devised efficient short-hand notation schemes to denote the basis set used in an ab initio calculation, although this does mean that a proliferation of abbreviations and acronyms are introduced. However, the codes are usually quite simple to understand. We shall concentrate on the notation used by Pople and co-workers in their Gaussian series of programs (see also the appendix to this chapter). 

Ab initio molecular orbital theory, (Wiley-Interscience 1986) by W. J. Hehre, L. Radom, P. v.R. Schleyer and J. A. Pople is an admirably detailed account of the use of the GAUSSIAN series of programs with a huge amount of detail on methodology and lots of results, mainly for organic molecules. 

The STO-3G, 3-21G, 3-21 G 6-31G, and 6-31G basis sets were developed by Pople and co-workers (see Hehre et al. Section 4.3) and are available in the widely used Gaussian series of programs (see Section 15.15). 

The 1998 Nobel prize in chemistry was shared by Walter Kohn, one of the developers of density-functional theory, and John A. Pople, one of the developers of the Gaussian series of programs and widely used Gaussian basis sets, the Pariser-Parr-Pople method, the CNDO and INDO methods, and one of the first to apply the MP and CC methods to molecular calculations. The Nobel committee noted that computational quantum chemistry is revolutionising the whole of chemistry. ... 

The Pople corrections for higher excitations in CISD calculations result in a method called quadratic (Q) CISD, which can be regarded as an approximation to the coupled-cluster methods discussed in a separate section below. QCISD is available in the Gaussian series of programs, along with analytical derivatives and a method for the estimation of triple excitations called QCISD(T). Note that in Gaussian, CISD on open-shell molecules is performed with UHF MOs. Therefore, for such molecules, the methods just named should really be called UQCISD or UQCISD(T), respectively. 

In the Gaussian series of programs, the properties of the correlated wavefunction are obtained only if the density=current keyword is supplied. 

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