Computer assisted generation of the matrix elements between contracted wavefunctions in a Complete Active Space scheme Original Research Article

Starting from a CAS–SCF calculation a sequence of contracted functions can be generated by applying strings of spin-traced replacement operators to the CAS–SCF solution. The laborious task of producing the Hamiltonian matrix elements between such functions can be substantially reduced making use of a computer algebra system. An implementation employing the MuPAD system is presented and illustrated.