Resonant inelastic X-ray scattering on atoms and simple molecules in the tender X-ray region

We present the main characteristics of the experimental set-up used to perform gas-phase RIXS studies in the tender X-ray range. A complete in-vacuum curved-crystal X-ray emission spectrometer in Johansson geometry has been built for a 2-6 key energy range with sub natural line-width energy resolution. The spectrometer operates in a dispersive geometry, employing a relatively large X-ray source placed inside the Rowland circle and a position sensitive detection of diffracted X-rays. A short review of the most recent experimental applications is given focusing on RIXS studies on isolated atoms and molecules. (C) 2012 Elsevier B.V. All rights reserved.