ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 13, Number 4
JKCSEZ 13(4)
August 20, 1969 

The MO's of maleic anhydride are calculated using the parameter values, hO.= 1, hO:= 2, kC=O= 1, kC-O= 0.8, and δαn= 2 × (0.3)n. With these MO's the interaction energies of the photochemical reaction of maleic anhydride (MA) with benzene are calculated using intermolecular orbital theory. It is shown that there are cases where the interaction energy includes a constant term and this term takes a great role in the photochemical interaction energy, and that with the calculated interaction energies the reaction mechanism is quite well explained. And it is proved that the photochemical reaction is possible for the second addition step of MA to benzene, and that the MA-benzene adduct should have the well-known stereochemical structure.