Research on gas phase molecules, liquids and free clusters

Investigating the interaction of light with molecules/clusters/liquids and the determination of the properties of these systems and/or the dynamics that occur under certain conditions, provides fundamental answers that are essential to the understanding of a myriad of complex processes.  Such processes span the entire scientific spectrum, from branches of physics and chemistry, to engineering and biology. Some of these occur in nature whilst others are important for industrial and technological advancement.

Specific examples that greatly impact our world include ionization processes and photoreactions that take place in the upper and lower atmosphere – contributing to climate and cloud formation, reactions relevant to industry – chemical, pharmaceutical and medical, and UV radiation damage to biological molecules that is known to adversely impact human health. Many of the above fields can benefit from the information gathered from Low Density Matter Research – i.e. research using samples in the gas-, cluster-, and, liquid- phases.

Low Density Matter research at MAX IV

Low Density Matter research has a long history at MAX IV/MAX-lab and a strong and successful LDM community has been active at the lab since its inception.

A variety of cutting-edge spectroscopic methods are essential to the work of our LDM community and at MAX IV we strive to meet the experimental needs of our ever -expanding and -evolving community.

We offer access to a number of LDM-relevant beamlines (highlighted within yellow boxes below) as well as a selection of mobile scientific equipment that, when fully developed/commissioned, will be available for use at these beamlines. For more information on the LDM facilities available at MAX IV click on the links to the right.




Experimental Techniques and Facilities for Low Density Matter Research at MAX IV

 AvailableIn commissioningUnder developmentFuture directions?
Experimental Techniques- Photoelectron spectroscopy

- APXPS using liquid jet

- Multi-coincidence spectroscopy (GPES

- COLTRIMS/REMI (ICE end station)

- NIPICO - Negative Ion Positive Ion Coincidence (FinEstBeAMS)

- MBES - Magnetic Bottle Electron Spectrometer (proposals prepared in collaboration with NANOMO research group, Univ. of Oulu, Finland).
RIXS (liquid/gas phase)
TRISS - Trapped Ion Spectrometer Setup (for trapped ion research at Veritas and FlexPES) Funding secured!!!
Project started.
Available Sample Delivery Systems- Molecular Jet / Cluster source (continuous mode)

- 2 x Liquid microjets (compatible with HIPPIE, FlexPES and FinEstBeAMS)

- Magnetron-based sputter source for metal particle beams (FlexPES)
- 1 x Liquid microjet (compatible with Veritas and FinEstBeAMS)

- Aerodynamic lens sample delivery system (FinEstBeAMS & later FlexPES) Funding secured!!!
- Molecular Jet source (pulsed mode)

- A gas cell for gas/phase RIXS (at Uppsala University)

- Liquid flat jet Funding secured!!!
- Electrospray ionisation source (planned as part of the TRISS project)
Operational modes available at the 1.5 GeV ringSingle bunch mode (offered ~1 week/semester)- Single Bunch Mode will be offered during ~1-2 weeks per year.
- Alternative bunch schemes under investigation (accelerator development group)
Soft X-ray ChopperFlexPES chopper - synchronisation with R1 bunchmarkerAt FinEst Funding secured!!!

Single-bunch operation: There will be a 1 week of single-bunch operation in the period September 2022 – February 2023 . If you want to apply for a beamtime with single-bunch operation only, you should indicate it clearly in your beamtime proposal. For more information please contact Noelle Walsh (email below).

We welcome input from our user community and potential users.

Questions? Suggestions for future research directions/equipment development?

Please contact Noelle Walsh (contact information below).


  • name Noelle Walsh