On The Photodesorption of CO$_2$ Ice Analogues: The Formation of Atomic C in The Ice and the Effect of The VUV Emission Spectrume

التفاصيل البيبلوغرافية
العنوان: On The Photodesorption of CO$_2$ Ice Analogues: The Formation of Atomic C in The Ice and the Effect of The VUV Emission Spectrume
المؤلفون: Sie, N. -E., Caro, G. M. Muñoz, Huang, Z. -H., Martín-Doménech, R., Fuente, A., Chen, Y. -J.
سنة النشر: 2020
المجموعة: Astrophysics
مصطلحات موضوعية: Astrophysics - Astrophysics of Galaxies, Astrophysics - Earth and Planetary Astrophysics
الوصف: CO$_2$ ice has a phase transition at 35 K when its structure changes from amorphous to crystalline. Using Reflection absorption Infrared Spectroscopy (RAIRS), \"Oberg et al. observed that the photodesorption yield of CO$_2$ ice deposited at 60 K and irradiated at 18 K is 40% lower than that of CO$_2$ ice deposited and irradiated at 18 K. In this work, CO$_2$ ices were deposited at 16-60 K and UV-irradiated at 16 K to rule out the temperature effect and figure out the relationship between photodesorption yield and ice structure. IR spectroscopy is a common method used for measurement of the photodesorption yield in ices. We found that undetectable C atoms produced in irradiated CO$_2$ ice can account for 33% of the amount of depleted CO$_2$ molecules in the ice. A quantitative calibration of QMS was therefore performed to convert the measured ion current into photodesorption yield. During various irradiation periods, the dominant photodesorbing species were CO, O$_2$, and CO$_2$, and their photodesorption yields in CO$_2$ ices deposited at different temperature configurations were almost the same, indicating that ice morphology has no effect on the photodesorption yield of CO$_2$ ice. In addition, we found that the lower desorption yield reported by Mart\'in-Dom\'enech et al. is due to a linear relationship between the photodesorption yield and the combination of energy distribution of Microwave-Discharge Hydrogen-flow Lamp (MDHL) and UV absorption cross section of ices.
Comment: 11 pages, 11 figures
نوع الوثيقة: Working Paper
DOI: 10.3847/1538-4357/ab06be
URL الوصول: http://arxiv.org/abs/2001.01590
رقم الأكسشن: edsarx.2001.01590
قاعدة البيانات: arXiv
الوصف
DOI:10.3847/1538-4357/ab06be