Local correlation in the virtual space in multireference singles and double configuration interaction

A method of using local correlation in both the internal and external spaces in MRSDCI is presented. For demonstration purposes, application of the local MRSDCI method to study a few simple potential energy surfaces and to compute some bond dissociation energies (BDEs) in organic molecules is discussed. Special emphasis is on the use of the local correlation method with multiconfigurational references and the ability of this method to yield smooth potential energy surfaces to describe bond cleavage.