BREAKDOWN OF THE SUPERPOSITION APPROXIMATION - ABINITIO MO CALCULATION OF THE TRIPLET POLARIZABILITY OF LI2CL+

We report ab initio MO calculations of the incremental triplet polarizability of Li2Cl+ at various configurations. The triplet polarizabilities are almost as large as the sum of the incremental pair polarizabilities and generally have the opposite sign. For this strongly interacting system, estimates of the triplet polarizability obtained from the Heller-Gelbart superposition approximation agree poorly with the ab initio values. However these errors are likely to be less serious for weakly interacting systems such as inert gases. © 1979 Taylor & Francis Ltd.