We show that large-basis-set configuration interaction calculations including all single and double excitations from a complete-active-space optimized by MCSCF methods recover an approximately constant fraction of the external correlation energy. Therefore, by scaling this contribution to the energy, more accurate potential energy curves, barrier heights to chemical reactions, and potential energy surfaces can be calculated.
Bibliographical noteFunding Information:
for stimulating analysis end for advrce and to Rozeanne StecMer for assistance with the calculations. This work was supported in part by the National Science Foundation under grant no. CHES3-17944.