Photoprocessing & Spectroscopy Labtorary
Department of Physics, National Central University
What are we doing?
- Photon-induced Desorption of Ices
- X-ray Irradiation of Ices
- VUV and EUV Photolysis of Ices
- Energetic Electron Irradiation of Ices
See descriptions below and more about us !
Current Works
The VUV absorption cross section of interstellar ice allows to estimate the number of absorbed photons per molecule for a given ice thickness. In our previous works, we have shown the importance of this parameter as the first necessary step toward photochemistry and photodesorption. We are therefore setting up a novel wavelength dependent photochemistry and photodesorption system at a VUV beamline in NSRRC, Taiwan. This VUV beamline can provides the photon flux up to 10¹⁴ photons/cm² in the energy range of 4−11 eV. With such a powerful monochromatic light source, we can study with unprecedented detail the effects induced by monochromatic photons on photochemistry and photodesorption of interstellar ices.
The expected results will be compared to those obtained from the broadband energy source, namely MDHL. While monochromatic sources allow a detailed study of the radiative processes in astrophysical ice analogs, the MDHL source resembles the radiation field in dense interstellar clouds where ice mantles are present.
Our Topics
Photon-induced Desorption of Ices
One of our research objectives is the photon-induced desorption of solid CO to explain why this species is observed in the gas phase toward cold clouds such as L183, in which CO is expected to condense onto grains on timescales shorter than the cloud lifetime, at temperatures below 20 K.
X-ray Irradiation of Ices
We used an energy tunable soft X-ray synchrotron beamline provided by NSRRC to study X-ray irradiation of interstellar ice analogs.
VUV and EUV Photolysis of Ices
Experiments of ice photolysis have shown that a large number and variety of molecules of prebiotic and biological interests, including many essential amino acids, sugars like ribose, and the nucleobase uracil, can be formed via VUV/EUV irradiation of astrophysical ice mixture analogs, and identified in the resulting samples with chromatographic techniques.
Energetic Electron Irradiation of Ices
Many types of radiation fields ubiquitous in interstellar and circumstellar regions can chemically process carbon monoxide, giving rise to a variety of effects going from chemical evolution to photodesorption. In our recent study, we exploit electrons in the middle-range energy (150-1000 eV), to explore the effects at energies closer to mean energies of primary electrons produced by cosmic-rays and X-rays impacting with molecular gas.