The simplest molecular orbital theory of π-conjugated molecular systems. It uses the following approximations: π-electron
approximation; LCAO representation of the π-molecular orbitals; neglect of electron-electron and nuclear-nuclear
repulsions (in fact, the assumption that these cancel). The diagonal elements of the
effective Hamiltonian, coulombic integrals, and the off-diagonal elements, resonance integrals, (accounted for only directly bonded atoms) are chosen as empirical parameters,
all overlap integrals being neglected.

Source:

PAC, 1999, *71*, 1919*
(Glossary of terms used in theoretical organic chemistry)
* on page 1944