Calculation of the differential photoionization cross-section of formaldehyde

The integral and the differential photoionization cross-sections of formaldehyde are computed in the random phase approximation (RPA) coupled with a K-matrix (KM) based technique. The molecular orbitals in the continuum are projected on suitable L2 special polynomial Gaussian functions. Ionization channels originating from the valence shell occupied orbitals are considered, both in separated and interacting channel (IC) approaches up to a photon energy of 45 eV. It is found that the channel coupling is important in order to reproduce some features in the absorption and ionization spectra.