  In this paper we discuss a method for calculating transfer integrals based on
the ZINDO Hamiltonian which requires only a single self consistent field on an
isolated molecule to be performed in order to determine the transfer integral
for a pair of molecules. This method is compared to results obtained by
projection of the pair of molecules' molecular orbitals onto the vector space
defined by the molecular orbitals of each isolated molecule. The two methods
are found to be in good agreement using three compounds as model systems:
pentacene, ethylene and hexabenzocoronene.
