Overview of Gaussian Theories

G3 Theory

G3 is an improvement over G2 theory in several ways and tries to reproduce effectively QCISD(T)/G3large
energies through a series of calculations at lower level. The G3large basis set is a slightly modified
version of the 6-311+G(3df,2p) basis set used in the G2 procedure. The G3 energy at 0 degrees Kelvin
E0(G3) is defined as:

The definition of the components being:

The necessary energies can be calculated most efficiently in the following sequence:


Overview of Gaussian Theories

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