Supervisors: Sergio Ioppolo + Herma Cuppen - Radboud University and HFML-FELIX
Research area and project description:
Infrared radiation influences icy dust grains as interstellar clouds evolve into star- and planet-forming regions, yet we do not know how absorbed vibrational energy moves through chemically complex ices or when it causes restructuring and molecular desorption. This PhD project will determine how ice composition, molecular environment and excitation wavelength control these processes.
The candidate will prepare astrophysically relevant mixed ices under ultrahigh-vacuum and cryogenic conditions. The experiments will combine major ice components (H2O, CO and CO2) with minority species such as methanol, aromatic and carbon-chain molecules, and selected amino acids. Infrared spectroscopy and mass spectrometry will be used to measure spectral fingerprints, energy dissipation, segregation, restructuring and desorption after wavelength-selective IR excitation. Targeted campaigns at the LISA end station of HFML-FELIX in Nijmegen will provide intense, tunable infrared radiation. Complementary experiments, sample preparation and data analysis will be carried out at Aarhus University.
The student will be based at Aarhus University and will undertake short research stays at FELIX, totalling at most a few months per year, working with co-supervisor Professor Herma Cuppen. Results will be interpreted together with InterCat2 collaborators developing molecular-dynamics and machine-learning models and will support the analysis of JWST ice observations. Validated spectra will be contributed to LIDA or equivalent databases.
The PhD position is funded by the Center of Excellence for Interstellar Catalysis (InterCat2), an interdisciplinary and international research environment connecting laboratory astrochemistry, theory and astronomical observations. The project will reveal how infrared radiation regulates the physical evolution of interstellar ices and the transfer of molecules from ice to gas during star and planet formation.
Please e-mail Sergio Ioppolo (s.ioppolo@phys.au.dk) or intercat@phys.au.dk to express your interest.
Supervisors: Sergio Ioppolo + Jes Jørgensen - University of Copenhagen
Research area and project description:
How does radiation transform the icy mantles on interstellar dust grains, and which molecules are released as stars and planets form? JWST now probes ices while ALMA maps related gas-phase molecules, but connecting these observations requires laboratory measurements under realistic conditions. This experimental PhD project will determine how energetic and thermal processing changes ice composition, structure, optical properties and molecular desorption.
Based in Sergio Ioppolo's laboratory at Aarhus University, the candidate will prepare pure, layered and mixed interstellar-ice analogues at 10-20 K under ultrahigh vacuum. Initial systems will include H2O, CO, CO2 and CH3OH, followed by selected complex organic molecules and N- and S-bearing species. FTIR spectroscopy, a cryogenic quartz-crystal microbalance, optical interferometry and time-resolved quadrupole mass spectrometry will be combined to obtain spectra, refractive indices, densities, desorption yields and thresholds.
Experiments at AU and the ASTRID2 synchrotron will expose the ices to wavelength-selected UV photons and 1-5 keV electrons. Short campaigns at HUN-REN Atomki in Hungary will extend the study to keV-MeV ion irradiation, providing analogues of solar particles and cosmic rays. Parallel diagnostics at AU and Atomki will enable direct comparison of photon-, electron- and ion-driven chemistry.
Together with co-supervisor Professor Jes Jørgensen and the BRIDGE observational PhD student at the University of Copenhagen, the candidate will connect the laboratory spectra and desorption data to JWST and ALMA observations. The project will create open spectral and desorption libraries and test whether observed gas-phase chemical diversity reflects release from processed ices or additional gas-phase chemistry. The position is funded by Independent Research Fund Denmark (DFF) through BRIDGE: From Laboratory Ices to Astronomical Observations (6208-00028B).
Please e-mail Sergio Ioppolo, s.ioppolo@phys.au.dk to express interest
