Incorporation of doubly excited configurations in calculating the benzene-cyanoethylene complex

A calculation by Pople's method with configuration interaction is presented for the weak complex of benzene with tetracyanoethylene incorporating doubly excited configurations; the bond strength is found as 1.8 kcal/mole, as well as the contributions from the charge-transfer and dispersion forces. The energies of the first four transitions are calculated, the lowest of which are of charge-transfer type.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, Vol. 16, No. 7, pp. 115–118, July, 1973.