An approximate method for calculating transfer integrals based on the ZINDO Hamiltonian

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.