Vacuum-UV spectroscopy of interstellar ice analogs: I. Absorption cross-sections of polar-ice molecules

Please use this identifier to cite or link to this item: https://ir.lib.ncu.edu.tw/handle/987654321/108444

Title:	Vacuum-UV spectroscopy of interstellar ice analogs: I. Absorption cross-sections of polar-ice molecules
Authors:	陳俞融;Cruz-Diaz, G. A.;Muñoz Caro, G. M.;Chen, Y.-J.;Yih, T.-S.
Contributors:	理學院物理學系
Keywords:	Absorption cross sections;Capture cross sections;Cross sections;Density;Estimates;Interstellar;Mantles;Spectroscopy
Date:	2014-02-01
Issue Date:	2026-04-23 14:49:05 (UTC+8)
Publisher:	EDP Sciences
Abstract:	摘要： Context. The vacuum-UV (VUV) absorption cross sections of most molecular solids present in interstellar ice mantles with the exception of H sub(2)O, NH sub(3), and CO sub(2) have not been reported yet. Models of ice photoprocessing depend on the VUV absorption cross section of the ice to estimate the penetration depth and radiation dose, and in the past, gas phase cross section values were used as an approximation. Aims. We aim to estimate the VUV absorption cross section of molecular ice components. Methods. Pure ices composed of CO, H sub(2)O, CH sub(3)OH, NH sub(3), or H sub(2)S were deposited at 8 K. The column density of the ice samples was measured in situ by infrared spectroscopy in transmittance. VUV spectra of the ice samples were collected in the 120-160 nm (10.33-7.74 eV) range using a commercial microwave-discharged hydrogen flow lamp. Results. We provide VUV absorption cross sections of the reported molecular ices. Our results agree with those previously reported for H sub(2)O and NH sub(3) ices. Vacuum-UV absorption cross section of CH sub(3)OH, CO, and H sub(2)S in solid phase are reported for the first time. H sub(2)S presents the highest absorption in the 120-160 nm range. Conclusions. Our method allows fast and readily available VUV spectroscopy of ices without the need to use a synchrotron beamline. We found that the ice absorption cross sections can be very different from the gas-phase values, and therefore, our data will significantly improve models that simulate the VUV photoprocessing and photodesorption of ice mantles. Photodesorption rates of pure ices, expressed in molecules per absorbed photon, can be derived from our data. 出版日期： 2014-02 出處： Astronomy and astrophysics (Berlin), 2014-02, Vol.562, p.A119-np 資源來源： EDP Sciences 識別號： ISSN: 0004-6361 識別號： EISSN: 1432-0746 識別號： DOI: 10.1051/0004-6361/201322140
Appears in Collections:	[Department of Physics] journal & Dissertation

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