FISSA · The Invisible made Visible:Far-Infrared Spectroscopy in Support of Astrochemistry

The Invisible made Visible: Far-Infrared Spectroscopy in Support of Astrochemistry

International astronomical facilities, in particular the Herschel Space Telescope, SOFIA and ALMA, are currently characterizing the interstellar medium (ISM) by collecting a huge amount of new THz spectral data that must be compared to THz laboratory spectra to be interpreted. The latter, however, are largely lacking, and this severely restricts the scientific impact of the astronomical observations. The aim of the outgoing part of this project is to produce laboratory THz spectra of interstellar ice analogues in support of astrochemistry. The overarching objective of this research project is to provide the scientific community with an extensive THz ice-database, which will allow quantitative studies of the ISM, and guide future astronomical observations of species in the solid phase. To achieve this goal, Dr. S. Ioppolo, the Marie Curie researcher scholar, spent the past two years (the outgoing phase of the fellowship) at Caltech being embedded in the laboratory group of Prof. G. A. Blake. There, the fellow acquired knowledge in THz spectroscopy techniques that he successfully used to design, construct and operate a THz Time-Domain Spectrometer (DTS) to acquire spectra of interstellar ice analogues in the range between 0.2 and 8 THz. The system is coupled to a FT-IR spectrometer to monitor the ices in the mid-IR (4000 - 500 cm-1). Since THz absorption modes are mostly dominated by intermolecular interactions, this unique THz TDS system allowed for the investigation of the structure of interstellar ice analogs. Such research clearly showed the potential of using THz TDS techniques to investigate not only the composition of interstellar ices, but also the chemistry and physics that lead to greater molecular complexity in space. Therefore, the project has a potential impact in astronomy, chemistry, biology, and in a wider sense in our society because it contributes to our understanding of complexity in the Universe and ultimately the origin of life. During the outgoing phase, the fellow performed numerous experiments that led so far to the publications of fourteen papers in high-impact peer-reviewed journals (i.e., Astrophys. J., Mon. Not. R. Astron. Soc., Phys. Chem. Chem. Phys., Rev. Sci. Instrum., Astron. Astrophys., Chem. Comm., and Space Sci. Rev.) and a book chapter. These results were presented nationally and internationally at twelve conferences in the States, Netherlands, and Italy. Over the course of the outgoing phase, the fellow collaborated internationally with groups in the States, Netherlands, France, UK, and Italy, and supervised master and PhD students in different institutions. He was also involved in a series of dissemination activities including the organization of meetings, lectures, and the construction of a website for the THz spectrometer project within the Prof. Blake group (web.gps.caltech.edu/~gab/index.html). The return phase started in August 2014 at the Radboud University of Nijmegen, the Netherlands. The ultimate goal of the return phase is to perform advanced experiments using non-linear pump-probe THz spectroscopy with the free electron laser (FEL) facility available in Nijmegen. These pioneering experiments are set to unlock details on dynamics in molecular physics at picosecond timescales. During the return phase, the fellow was embedded in the groups of Dr. H. M. Cuppen (Theoretical Chemistry, Institute for Molecules and Materials), Prof. D. H. Parker (Department of Molecular and Laser Physics, Institute for Molecules and Materials), and Dr. B. Redlich (facility manager of FELIX Facility). At the end of 2014, Dr. Ioppolo was awarded a prestigious Royal Society University Research Fellowship that allowed Dr. Ioppolo to join the Open University (UK) as a faculty member of the Department of Physical Sciences in January 2015. This is a clear indication of the success of the Marie Curie International Outgoing Fellowship project and the scientific quality of the fellow. Therefore, the project was terminated on December 31, 2014. The early termination did not affect the return phase as all the preliminary work is done and the experiments at the FEL are still scheduled to be performed at the FELIX Facility in April 2015. Therefore, the project has become an international collaboration between the Radboud University of Nijmegen (NL) and the Open University in Milton Keynes (UK).

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