Mass resolved photoionization and photodissociation of CO following C(1s) excitation

Photoionization and photodissociation of C(1s) core excited carbon monoxide has been studied in the range 285-320 eV using mass spectroscopy at the undulator beam line 51 at the Swedish synchrotron facility MAX in Lund. Spectra of C1, O+, CO+, C2+, O2+ and CO2+ were recorded at a photon resolution comparable to high resolution photoabsorption measurements. The results essentially agree with earlier investigations of the C(1s) to pi * excitation except for an earlier unobserved strong enhancement of the upsilon '=4 resonance. However, surprising results are obtained for the relative intensities of C(1s) excitations to singly and doubly excited Rydberg levels in the different fragmentation channels.