The FlexPES (Flexible PhotoElectron Spectroscopy) beamline caters for the experimental needs of both Surface/Material Science and Low Density Matter user communities offering the possibility to perform a variety of photoemission and soft X-ray absorption experiments in the photon energy range 40 – 1500 eV. The two-branch configuration with double-striped toroidal refocusing mirrors ensures maximum flexibility – up to four endstations can be accommodated on the two branches of the beamline simultaneously, and each of these endstations can avail of different focusing conditions. The end stations offer a diverse range of experimental techniques, detectors and sample handling facilities and can be used with a variety of sample delivery systems.
The Surface and Material Science (SMS) branch is dedicated to UHV (10-6 to 10-11 mbar) experiments on solid samples. It hosts a versatile photoemission end station, providing visiting scientists with different modes of PES and soft-XAS techniques and a variety of sample transfer and treatment facilities. The research focus is on surface phenomena, synthesis and reactions, thin films relevant for catalysis, solar cells, sensors and other energy-related applications, protective coatings, 2D- and nano-materials. Downstream from this end station there is a free port for a second (user-defined) experiment.
The Low Density Matter (LDM) branch accommodates research on gas-phase samples (molecules/clusters), liquid samples and even some surface science experiments (on solar cells, Li-ion batteries, etc) in the pressure range 10-6 to 10-9 mbar. A permanent photoelectron spectroscopy end station will be used for XPS and XAS experiments. The second port on the LDM branch can accommodate user-defined experiments or the new ICE end station for multi-coincidence spectroscopy (under development). A flexible sample molecular jet/cluster source and a liquid jet source (both under development) will be available to the MAX IV LDM community.

Techniques High-resolution XPS and XAS, resonant photoemission (ResPES) and angle-resolved valence band spectroscopy (ARPES), electron-ion coincidence experiments
Beam Size From 50 um to 2 mm
Energy Range 40 to 1500 eV
Time Scales Seconds
Samples From solid surfaces, thin films, adsorbates, nanostructures to free clusters, gases and liquids


Acid-base equilibria: not exactly like you remember in chemistry class

Work published in the Royal Society of Chemistry with the support of the Helmholtz Association through the Center for Free-Electron Laser Science at DESY. MAX IV Laboratory, Lund University, Sweden,  European Research Council (ERC) under the European Union’s Horizon 2020 and the Academy of Finland.   Remember doing titrations in chemistry class? Adding acid drop-by-drop