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.
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