Photon-induced fragmentation of a full set of chlorinated methanes (CH3Cl, CH2Cl2, CHCl3, CCl4) has been investigated both experimentally and computationally. Using synchrotron radiation and electron-ion coincidence measurements, the dissociation processes were studied after chlorine 2p electron excitation. Experimental evidence for CH3Cl and CH2Cl2 contains unique features suggesting that fast dissociation processes take place. By contrast, CHCl3 and CCl4 molecules do not contain the same features, hinting that they experience alternative mechanisms for dissociation and charge migration. Computational work indicates differing rates of charge movement after the core-excitation, which can be used to explain the differences observed experimentally.

State-of-the-art Argon KLL Auger spectra measured using photon energies of hν = 3216 eV and 3400 eV are presented along with an Ar [1s] photoelectron spectrum (squared brackets indicate holes in the respective orbital). The two different photon energies used for measuring the Auger spectra allow distinguishing between the shake transitions during the Auger decay and the Auger transitions of the photoelectron satellites. A complete assignment of satellite transitions is provided, partially baseed on configuration interaction calculations. In addition, Artransitions are observed, which can be explained by knock-down transitions leading to a direct exchange of angular momenta between the excited electron and the Auger electron. The lifetime broadenings of the Ar [2s] single core-hole state and the [2s 2 ] as well as [2s2p] double core-hole states are also determined, confirming previously observed trends for double core-hole states.

We present an extended theoretical study of two-colour doubly resonant photoionization of helium involving two doubly excited states below the N = 2 ionization threshold. We model the effects of a strong laser coupling between the lowest 1Po and the selected 1Se, 1Pe and 1De doubly excited states on the photoelectron (photoion) yield by taking into account the spatio-temporal structure of the pulses and by considering the effects of the neighbouring resonance states. We show that the laser coupling results in a measurable modification of the line profiles and in a reduction of the photoelectron yield under resonant or near-resonant conditions.

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