where the matrix D λ,k (t) consists of the kth row and column of D λ (t) only, with zeros elsewhere. The time-series data µ λ,k (t) admit a Fourier representation analogous to Eq. ( ), to which one may apply Padé approximants in the same way. The corresponding Fourier transform, µ λ,k (ω), affords a spectrum that can be associated with occupied MO ψ k . According to Eq. ( ) and the linearity of the Fourier transform, the sum of these orbital-indexed spectra must afford the parent TDKS spectrum, but various partitions of the sum in Eq. ( ) might be considered. In the present work, we will always sum together all MOs corresponding to a given elemental edge, meaning for example the two O(1s) orbitals or the four C(1s) orbitals in the methionine molecule will be considered as a group and not decomposed any further.