High-resolution photoelectron spectroscopy in atoms and molecules

New features are revealed by critically combining high photon resolution from the Advances Light Source and differential photoelectron spectroscopic techniques. Two LS-forbidden doubly-excited resonances have been observed in the 3p(3/2,1/2)(-1) partial cross-sections of Ar which exhibit mirroring profiles, resulting in complete cancellation in the total photoionization cross-section as was predicted by Liu and Starace [Phys. Rev. A 59, R1731 (1999)]. We will also discuss recent preliminary measurements on the vibrational structure and partial rates of resonant Auger decay of the N 1s -->2 pi core excitation in nitric oxide.