Size-consistent self-consistent configuration interaction from a complete active space:: Excited states

The self-consistent size consistent on a complete active space singly and doubly configuration interaction (SC)(2)CAS-SDCI method is applied to excited states. The (SC)(2) correction is performed on a closed shell state, and the excited states are obtained by diagonalization of the dressed matrix. A theoretical justification of the transferability of the improvement concerning the dressing state to all roots of the matrix is presented. The method is tested by three tests on the spectrum of small molecules. (C) 1998 American Institute of Physics. [S0021-9606(98)30843-0].