CC BY
9*
ALT'23
The 30th International Conference on Advanced Laser Technologies
N-I-22
THz-IR dielectric spectroscopy of astrophysical ices: Recent achievements and challenges.
A.A. Gavdush1, F. Kruczkiewicz2,3, B. M. Giuliano2, B. Müller2, G. A. Komandin1, K. I.
Zaytsev1, A. V. Ivlev2, P. Caselli2
1- Prokhorov General Physics Institute of the Russian Academy of Sciences, Russia, 119991 Moscow, Russia 2- Max-Planck-Institut für Extraterrestrische Physik, Gießenbachstraße 1, Garching 85748, Germany 3- Aix-Marseille Univ, CNRS, CNES, LAM, Marseille, France
Understanding the chemical and physical properties of molecular clouds, in which the star and planet formation process takes place, is directly related to the correct estimation of the amount of gas contained in them. This problem is one of many in the list of relevant astrophysical problems [ 1 -4] requiring the knowledge of broadband dielectric properties of interstellar and circumstellar laboratory ice analogues. The complex dielectric permittivity of ices is essential while modeling the dust continuum emission, radiative transfer in dense and cold University regions. Despite the importance of such parameters there is still a lack of data concerning dielectric properties of ices in terahertz (THz) and infrared (IR) ranges of spectra. Series of recent works from our scientific group [5, 6] is focused on solving such a problem. We developed original methods for processing the experimental data obtained by means of THz pulsed spectroscopy (TPS) and Fouriertransform infrared spectroscopy (FTIR). The possibility of direct reconstruction of the ices complex dielectric permittivity in the broad spectral range is a primary result of our studies. The algorithm of direct reconstruction takes into account the possibility of retrieving amplitude and phase information for TPS measurements and proposes an approach of merging TPS and FTIR data with the solution of the problem of eliminating uncertainties introduced by the Kramers-Kronig relations. Complex dielectric properties of several ices, including carbon monoxide and carbon dioxide ices, were studied in the THz-IR range. The obtained results are analyzed in terms of analytical Lorentz dielectric models with attribution to particular vibrational modes. The most promising areas for further research include ice structure investigation, study of the light scattering in ice, study of the regimes for producing ice samples, annealing of the ices. A review of the unanswered questions and promising results is a final part of the talk. This work was supported by the Russian Science Foundation (RSF), Project # 22-72-00092.
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[3] D.V. Mifsud et al., The Role of Terahertz and Far-IR Spectroscopy in Understanding the Formation and Evolution of Interstellar Prebiotic Molecules, Frontiers in Astronomy and Space Sciences, vol. 8 (2021).
[4] D.V. Mifsud et al., Sulfur Ice Astrochemistry: A Review of Laboratory Studies, Space Science Reviews, vol. 217(1), pp. 14 (2021).
[5] B.M. Giuliano et al., Broadband spectroscopy of astrophysical ice analogues: I. Direct measurement of the complex refractive index of CO ice using terahertz time-domain spectroscopy, Astronomy & Astrophysics, vol. 629, pp. A112 (2019).
[6] A.A. Gavdush et al., Broadband spectroscopy of astrophysical ice analogues: II. Optical constants of CO and CO2 ices in the terahertz and infrared ranges, Astronomy & Astrophysics, vol. 667, pp. A49 (2022).
