Some self-consistent perturbation calculations of 1J(CC)

Self-consistent perturbation calculations of 70 ¹J(CC) values are reported within the INDO framework. A least-squares agreement between the calculated and observed couplings, for a variety of bond multiplicities, provides values of 13.503 au^?6 and 5.072 au^?6 for (S_C²(O))² and 〈r^?3〉_C², respectively. The non-contact terms are found to be important in cases of multiple bonding.