|| Y. Kim and R. Kaiser, “On the formation of amines (RNH2) and the cyanide anion (CN−) in electron-irradiated ammonia-hydrocarbon interstellar model ices,” The Astrophysical Journal, vol. 729, no. 1, p. 68, 2011.|
 W. Grundy, R. Binzel, B. Buratti, J. Cook, D. Cruikshank, C. Dalle Ore, A. Earle, K. Ennico, C. Howett, A. Lunsford et al., “Surface compositions across Pluto and Charon,” Science, vol. 351, no. 6279, p. aad9189, 2016.
 W. Grundy, D. Cruikshank, G. Gladstone, C. Howett, T. Lauer, J. Spencer, M. Summers, M. Buie, A. Earle, K. Ennico et al., “The formation of Charon’s red poles from seasonally cold-trapped volatiles,” Nature, vol. 539, no. 7627, pp. 65–68, 2016.
 Y.-J. Chen, K.-J. Chuang, G. M. Caro, M. Nuevo, C.-C. Chu, T.-S. Yih, W.-H. Ip, and C.-Y. Wu, “Vacuum ultraviolet emission spec- trum measurement of a microwave-discharge hydrogen-flow lamp in several configurations: application to photodesorption of CO ice,” The Astrophysical Journal, vol. 781, no. 1, p. 15, 2013.
 J. Kissel, F. Krueger, J. Silén, and B. Clark, “The cometary and interstellar dust analyzer at comet 81P/Wild 2,” Science, vol. 304, no. 5678, pp. 1774–1776, 2004.
 L. d’Hendecourt and L. Allamandola, “Time dependent chemistry in dense molecular clouds. III-infrared band cross sections of molecules in the solid state at 10 K,” Astronomy and Astrophysics Supplement Series, vol. 64, pp. 453–467, 1986.
 J. C. Cook, S. J. Desch, T. L. Roush, C. A. Trujillo, and T. Geballe, “Near-infrared spectroscopy of Charon: Possible evidence for cryo-
volcanism on Kuiper belt objects,” The Astrophysical Journal, vol. 663, no. 2, p. 1406, 2007.
 M. E. Brown and W. M. Calvin, “Evidence for crystalline water and ammonia ices on Pluto’s satellite Charon,” Science, vol. 287, no. 5450, pp. 107–109, 2000.
 W. A. Hoey, S. K. Yeoh, L. M. Trafton, D. B. Goldstein, and P. L. Varghese, “Rarefied gas dynamic simulation of transfer and escape in the Pluto–Charon system,” Icarus, no. 287, pp. 87–102, 2017.
 G. R. Gladstone, W. R. Pryor, and S. A. Stern, “Lyα@ pluto,” Icarus, vol. 246, pp. 279–284, 2015.
 S. Kundu, V. S. Prabhudesai, and E. Krishnakumar, “Electron in- duced reactions in condensed mixtures of methane and ammonia,” Physical Chemistry Chemical Physics, vol. 19, no. 37, pp. 25 723– 25 733, 2017.
 S. Stern, J. Kammer, G. Gladstone, A. Steffl, A. Cheng, L. Young, H. Weaver, C. Olkin, K. Ennico, J. W. Parker et al., “New Horizons constraints on Charon’s present day atmosphere,” Icarus, vol. 287, pp. 124–130, 2017.
 T.-F. Hsieh, L.-R. Huang, S.-C. Chung, T.-E. Dann, P.-C. Tseng, C. Chen, and K.-L. Tsang, “Design of a high-flux and high- resolution VUV bending-magnet beamline,” Journal of synchrotron radiation, vol. 5, no. 3, pp. 562–564, 1998.
 H. Imanaka, B. N. Khare, J. E. Elsila, E. L. Bakes, C. P. McKay, D. P. Cruikshank, S. Sugita, T. Matsui, and R. N. Zare, “Labora- tory experiments of Titan tholin formed in cold plasma at various pressures: implications for nitrogen-containing polycyclic aromatic compounds in Titan haze,” Icarus, vol. 168, no. 2, pp. 344–366, 2004.
 M. Moore and R. Hudson, “Infrared study of ion-irradiated water- ice mixtures with hydrocarbons relevant to comets,” Icarus, vol. 135, no. 2, pp. 518–527, 1998.
 J. A. Noble, P. Theule, F. Borget, G. Danger, M. Chomat, F. Du- vernay, F. Mispelaer, and T. Chiavassa, “The thermal reactivity of HCN and NH3 in interstellar ice analogues,” Monthly Notices of the Royal Astronomical Society, vol. 428, no. 4, pp. 3262–3273, 2012.
 J.-B. Bossa, P. Theulé, F. Duvernay, F. Borget, and T. Chiavassa, “Carbamic acid and carbamate formation in NH3+CO2 ices–UV irradiation versus thermal processes,” Astronomy & Astrophysics, vol. 492, no. 3, pp. 719–724, 2008.
 M. Moore and R. Hudson, “Infrared study of ion-irradiated N2- dominated ices relevant to Triton and Pluto: Formation of HCN and HNC,” Icarus, vol. 161, no. 2, pp. 486–500, 2003.
 Y. Kim and R. Kaiser, “Abiotic Formation of Carboxylic Acids (RCOOH) in Interstellar and Solar System Model Ices,” The As- trophysical Journal, vol. 725, no. 1, p. 1002, 2010.
 G. Socrates, “Infrared and Raman Characteristic Group Frequen- cies, 3rd,” 2001.
 C. J. Bennett and R. I. Kaiser, “The formation of acetic acid (CH3COOH) in interstellar ice analogs,” The Astrophysical Jour- nal, vol. 660, no. 2, p. 1289, 2007.
 W. Zheng, D. Jewitt, Y. Osamura, and R. I. Kaiser, “Formation of nitrogen and hydrogen-bearing molecules in solid ammonia and im- plications for solar system and interstellar ices,” The Astrophysical Journal, vol. 674, no. 2, p. 1242, 2008.
 R. Hudson and M. Moore, “Reactions of nitriles in ices relevant to Titan, comets, and the interstellar medium: formation of cyanate ion, ketenimines, and isonitriles,” Icarus, vol. 172, no. 2, pp. 466– 478, 2004.
 C. J. Bennett, C. S. Jamieson, Y. Osamura, and R. I. Kaiser, “Laboratory studies on the irradiation of methane in interstellar, cometary, and solar system ices,” The Astrophysical Journal, vol. 653, no. 1, p. 792, 2006.
 S. Irle and K. Morokuma, “A molecular orbital study on H and H2 elimination pathways from methane, ethane, and propane,” The Journal of Chemical Physics, vol. 113, no. 15, pp. 6139–6148, 2000.
 G. Cruz-Diaz, G. M. Caro, Y.-J. Chen, and T.-S. Yih, “Vacuum-UV spectroscopy of interstellar ice analogs-I. Absorption cross-sections of polar-ice molecules,” Astronomy & Astrophysics, vol. 562, p. A119, 2014.
 ——, “Vacuum-UV spectroscopy of interstellar ice analogs-II. Ab- sorption cross-sections of nonpolar ice molecules,” Astronomy & As- trophysics, vol. 562, p. A120, 2014.
 S. J. Blanksby and G. B. Ellison, “Bond dissociation energies of organic molecules,” Accounts of chemical research, vol. 36, no. 4, pp. 255–263, 2003.
 J.-B. Bossa, D. Paardekooper, K. Isokoski, and H. Linnartz, “Methane ice photochemistry and kinetic study using laser desorp- tion time-of-flight mass spectrometry at 20 K,” Physical Chemistry Chemical Physics, vol. 17, no. 26, pp. 17 346–17 354, 2015.
 B. P. Tsai and J. H. Eland, “Mass spectra and doubly charged ions in photoionization at 30.4 nm and 58.4 nm,” International Journal of Mass Spectrometry and Ion Physics, vol. 36, no. 2, pp. 143–165, 1980.
 N. Ligterink, E. Tenenbaum, and E. Van Dishoeck, “Search for methylamine in high mass hot cores,” Astronomy & Astrophysics, vol. 576, p. A35, 2015.
 M. K. Georgieva and E. A. Velcheva, “Computational and experi- mental studies on the IR spectra and structure of the simplest ni- triles (C1 and C2), their anions, and radicals,” International journal of quantum chemistry, vol. 106, no. 6, pp. 1316–1322, 2006.