The CVS approximation extends standard excitedstate methods to core-level states by eliminating the amplitudes associated with all but a small number of occupied MOs. This reduces the computational cost drastically, and furthermore separates the highly excited core states from the continuum. It also allows the separation of K-edge spectra from L-and M-edge spectra. For the K-edge spectra examined here, the CVS active space consists of the 1s orbitals for the element in question, along with the entire virtual space. All core-level TD-DFT and DFT/CIS calculations reported here invoke the CVS approximation, which affords negligible errors for K-edge spectra. In molecules containing more than one atom with the same atomic number, all of the 1s orbitals for the element in question are included in the active space.