semi-empirical quantum mechanical methods
Methods which use parameters derived from experimental data to simplify computations. The simplification may occur at various levels: simplification of the Hamiltonian (e.g., as in the @ET07032@), approximate evaluation of certain molecular integrals (see, for example, @ZT07132@), simplification of the wavefunction (for example, use of a Pi (π) electron approximation as in @PT07088@ method), etc.
PAC, 1999, 71, 1919. (Glossary of terms used in theoretical organic chemistry) on page 1962 [Terms] [Paper]