Photoionization and photo-induced molecular fragmentation are central aspects in the interactions between particles and light. The mechanisms involved in photoabsorption and the subsequent ionization and relaxation vary in different photon energy regimes. I will present work concerning photo-induced ionization, dissociation and inter-atomic interactions using various photon sources. In our investigation of fragmentation of glycine molecules with x-rays, we deconvolute dissociation pathways and show the kinetics dependence of the fragmentation on photon energies. We investigated ionization of endohedral fullerene Ho3N@C80 with near infrared intense laser pulses and the results reveal geometry-based enhancement of photoionization. Using short x-ray pulses from free electron lasers, we probed the explosion of highly charged C60 molecular ions. I will also present our progress in using XUV short pulse to study inter-atomic or inter-molecular interactions in dopant clusters.
