[en] MAX IV Laboratory, a synchrotron facility in Lund, has selected TANGO as the control system framework for the entire facility. On the beamlines that are being built the Python-based SCADA (supervisory control and data acquisition) system Sardana will be used for experimental control. SPECIES, one out of eight new soft X-ray beamlines, is used as a test bench for evaluating the chosen standards. Sardana is used to control the energy setting of the PGM (plane grating monochromator) as well as to provide macros and other utilities for the user. Generic Taurus GUIs and a SVG-synoptic give the user a way to interact with the control system and display relevant information. The standardized graphical interfaces give a familiar look and feel across the entire facility. All motorized axes are controlled with the IcePAP motion controller. For the axes of the PGM, the IcePAP driver operates in hardware closed loop. Special care is taken in order to avoid slow and inaccurate movements of the PGM energy due to the non-linear relationship between the motors and the angular encoders. (author)

[en] A review is presented of some recent advancements in resonant soft X-ray fluorescence spectroscopy applied to molecules. The concept of inelastic scattering is discussed for molecules with an element of symmetry, which introduces degeneracy or near-degeneracy of core excited states. The potential of the symmetry selection rules associated with resonant X-ray fluorescence is illustrated in studies of electronic structure as well as molecular dynamics. The use of polarized photons for exciting X-ray emission is discussed, and examples are presented where anisotropy of X-ray emission provides more detailed information. A brief section discusses the experimental considerations relevant for the spectroscopic technique. (orig.)

[en] A grazing-incidence grating spectrometer has been used for the investigation of the undulator radiation from beamline 411 at MAX-lab. The direct detection of undulator light is expected to obtain the information of the quality of the undulator. Regular undulator radiation and some higher harmonics were observed. The effects of electronic beam coupling and Landau cavities have been studied. The experiment presents an easy and quick method to characterize the undulator radiation before the permanent monochromator is installed. (author)

[en] Resonant inelastic x-ray scattering spectra excited at the fluorine K resonances of SF₆ have been recorded. While a small but significant propensity for electronically parity-allowed transitions is found, the observation of parity-forbidden electronic transitions is attributed to vibronic coupling that breaks the global inversion symmetry of the electronic wavefunction and localizes the core hole. The dependence of the scattering cross section on the polarization of the incident radiation and the scattering angle is interpreted in terms of local π/σ symmetry around the S–F bond. This symmetry selectivity prevails during the dissociation that occurs during the scattering process. (paper)

[en] We have studied the spectral features of Cl L_II,III resonant x-ray Raman scattering of HCl molecules in gas phase both experimentally and theoretically. The theory, formulated in the intermediate-coupling scheme, takes into account the spin-orbital and molecular-field splittings in the Cl 2p shells, as well as the Coulomb interaction of the core hole with unoccupied molecular orbitals. Experiment and theory display nondispersive dissociative peaks formed by decay transitions in both molecular and dissociative regions. The molecular and atomic peaks collapse in a single narrow resonance because the dissociative potentials of core-excited and final states are parallel to each other along the whole pathway of the nuclear wave packet