SLS Micro-Reactor

Using state-of-the-art X-ray spectro-microscopic techniques at the Swiss Light Source, we develop new environmental micro-reactors, which allow tracking chemistry in particles in situ while being exposed to water vapor, oxidants or light. One recent novel example is directed at observing when ice forms and to track the physical and chemical properties of ice nucleating particles with 35 nm spatial resolution. This is the first time ice nucleation has been measured in-situ in an X-ray microscope. The main technical challenge was temperature, and thus relative humidity control, while maintaining X-ray transparency. 

Beamline: PolLux 

STXM Ice Cell
teaser for STXM

Scanning Transmission Microscopy for Environmental and Energy Research

We develop Scanning Transmission X-ray Microspectroscopy for environmental and energy research at the Swiss Light Source.

Aerosol Multiphase Photochemistry

Multiphase Photochemistry

The interplay between reactive oxygen species and the multiphase chemistry of nitrogen, halogen and secondary organic species in aerosol particles. Reactive oxygen species are at the origin of redox processes within the aqueous phase of aerosol particles containing secondary organic and inorganic species. The consequences are halogen and nitrogen oxides recycling, formation and loss of organics, which are all implicated in atmospheric oxidation capacity as well as the burden and health impact of aerosol particles. 

  • Corral Arroyo P, David G, Alpert PA, Parmentier EA, Ammann M, Signorell R
    Amplification of light within aerosol particles accelerates in-particle photochemistry
    Science. 2022; 376(6590): 293-296. https://doi.org/10.1126/science.abm7915
    DORA PSI
  • Alpert PA, Boucly A, Yang S, Yang H, Kilchhofer K, Luo Z, et al.
    Ice nucleation imaged with X-ray spectro-microscopy
    Environmental Science: Atmospheres. 2022; 2(3): 335-351. https://doi.org/10.1039/D1EA00077B
    DORA PSI
  • Alpert PA, Dou J, Corral Arroyo P, Schneider F, Xto J, Luo B, et al.
    Photolytic radical persistence due to anoxia in viscous aerosol particles
    Nature Communications. 2021; 12(1): 1769 (8 pp.). https://doi.org/10.1038/s41467-021-21913-x
    DORA PSI
  • Dou J, Alpert PA, Corral Arroyo P, Luo B, Schneider F, Xto J, et al.
    Photochemical degradation of iron(III) citrate/citric acid aerosol quantified with the combination of three complementary experimental techniques and a kinetic process model
    Atmospheric Chemistry and Physics. 2021; 21(1): 315-338. https://doi.org/10.5194/acp-21-315-2021
    DORA PSI
  • Forster J-D, Gurk C, Lamneck M, Tong H, Ditas F, Steimer SS, et al.
    MIMiX: a multipurpose in situ microreactor system for X-ray microspectroscopy to mimic atmospheric aerosol processing
    Atmospheric Measurement Techniques. 2020; 13(7): 3717-3729. https://doi.org/10.5194/amt-13-3717-2020
    DORA PSI
  • Mahrt F, Alpert PA, Dou J, Grönquist P, Arroyo PC, Ammann M, et al.
    Aging induced changes in ice nucleation activity of combustion aerosol as determined by near edge X-ray absorption fine structure (NEXAFS) spectroscopy
    Environmental Science: Processes and Impacts. 2020; 22(4): 895-907. https://doi.org/10.1039/C9EM00525K
    DORA PSI
  • Alpert PA, Corral Arroyo P, Dou J, Krieger UK, Steimer SS, Förster J-D, et al.
    Visualizing reaction and diffusion in xanthan gum aerosol particles exposed to ozone
    Physical Chemistry Chemical Physics. 2019; 21(37): 20613-20627. https://doi.org/10.1039/C9CP03731D
    DORA PSI
  • Liati A, Schreiber D, Alpert PA, Liao Y, Brem BT, Corral Arroyo P, et al.
    Aircraft soot from conventional fuels and biofuels during ground idle and climb-out conditions: electron microscopy and X-ray micro-spectroscopy
    Environmental Pollution. 2019; 247: 658-667. https://doi.org/10.1016/j.envpol.2019.01.078
    DORA PSI
  • Alpert PA, Corral Arroyo P, Dou J, Krieger UK, Steimer SS, Förster J-D, et al.
    Imaging molecular reaction and diffusion in organic aerosol particles
    Microscopy and Microanalysis. 2018; 24(Suppl. 2): 496-497. https://doi.org/10.1017/S143192761801471X
    DORA PSI
  • Alpert PA, Ciuraru R, Rossignol S, Passananti M, Tinel L, Perrier S, et al.
    Fatty acid surfactant photochemistry results in new particle formation
    Scientific Reports. 2017; 7(1): 12693 (11 pp.). https://doi.org/10.1038/s41598-017-12601-2
    DORA PSI