[1] [1] Miller S L. A production of amino acids under possible primitive Earth conditions [J]. Science, 1953, 117(117): 528-529.

[2] [2] Clarke D W, Ferris J P. Chemical evolution on Titan: Comparisons to the prebiotic Earth [J]. Origins of Life and Evolution of the Biosphere, 1997, 27: 225-248.

[3] [3] Lunine J I, Mckay C P. Surface-atmosphere interactions on Titan compared with those on the pre-biotic Earth [J]. Advances in Space Research, 1995, 15(3): 303-311.

[4] [4] Raulin F, Bruston P, Coll P, et al. Exobiology on Titan [J]. Journal of Biological Physics, 1995, 20(1): 39-53.

[5] [5] Raulin F, Brasse C, Poch O, et al. Prebiotic-like chemistry on Titan [J]. Chemical Society Reviews, 2012, 41(16): 5380-5393.

[6] [6] Coustenis A, Jennings D E, Nixon C A, et al. Titan trace gaseous composition from CIRS at the end of the Cassini-Huygens prime mission [J]. Icarus, 2010, 207(1): 461-476.

[7] [7] Torokova L, Watson J, Krcma F, et al. Gas chromatography analysis of discharge products in N2-CH4 gas mixture at atmospheric pressure: Study of mimic Titan′s atmosphere [J]. Contributions to Plasma Physics, 2015, 55(6): 470-480.

[8] [8] Pintassilgo C D, Loureiro J. Production of hydrocarbons and nitriles using a afterglow plasma for simulation of Titan′s atmosphere [J]. Planetary and Space Science, 2009, 57(13): 1621-1630.

[9] [9] Fujii T, Arai N. Analysis of N-containing hydrocarbon species produced by a CH4/N2 microwave discharge: Simulation of Titan′s atmosphere [J]. Astrophysical Journal, 1999, 519(2): 858-863.

[10] [10] Jeilani Y A, Nguyen H T, Cardelino B H, et al. Free radical pathways for the prebiotic formation of xanthine and isoguanine from formamide [J]. Chemical Physics Letters, 2014, 598(598): 58-64.

[11] [11] Gupta V P, Rawat P, Singh R N, et al. Formation of 2-imino-malononitrile and diaminomaleonitrile in nitrile rich environments: A quantum chemical study [J]. Computational and Theoretical Chemistry, 2012, 983: 7-15.

[12] [12] Ferus M, Civis S, Mladek A, et al. On the road from formamide ices to nucleobases: IR-spectroscopic observation of a direct reaction between cyano radicals and formamide in a high-energy impact event [J]. Journal of the American Chemical Society, 2012, 134(51): 20788-20796.

[13] [13] Ferus M, Nesvorny D, Sponer J, et al. High-energy chemistry of formamide: A unified mechanism of nucleobase formation [J]. Proceedings of the National Academy of Sciences, 2015, 112(3): 657-662.

[14] [14] Ferus M, Michalcikova R, Shestivska V, et al. High-energy chemistry of formamide: A simpler way for nucleobase formation [J]. Journal of Physical Chemistry A, 2014, 118(4): 719-736.

[15] [15] Jeilani Y A, Nguyen H T, Newallo D, et al. Free radical routes for prebiotic formation of DNA nucleobases from formamide [J]. Physical Chemistry Chemical Physics, 2013, 15(48): 21084-21093.

[17] [17] Li P, Fan W Y. The CN free radical in acetonitrile discharges [J]. Journal of Applied Physics, 2003, 93(12): 9497-9502.

[18] [18] Dilecce G, Ambrico P F, Scarduelli G, et al. CN(B2Σ+) formation and emission in a N2-CH4 atmospheric pressure dielectric barrier discharge [J]. Plasma Sources Science and Technology, 2009, 18(1): 127-130.

[19] [19] Grigorian G, Cenian A. Formation and excitation of CN molecules in He-CO-N2-O2 discharge plasmas [J]. Plasma Chemistry and Plasma Processing, 2011, 31(2): 337-352.

[20] [20] Ram R S, Wallace L, Bernath P F. High resolution emission spectroscopy of the A2Σ+-X2Σ+ (red) system of 12C14N [J]. Journal of Molecular Spectroscopy, 2010, 263(1): 82-88.

[21] [21] Western C M, Billinghurst B E. Automatic and semi-automatic assignment and fitting of spectra with PGOPHER [J]. Physical Chemistry Chemical Physics, 2019, 21(26): 13986-13999.

[23] [23] Mazankova V, Torokova L, Krcma F, et al. The influence of CO2 admixtures on the product composition in a nitrogen-methane atmospheric glow discharge used as a prebiotic atmosphere mimic [J]. Origins of Life and Evolution of the Biosphere, 2016, 4(4): 1-8.

[24] [24] Fleury B, Carrasco N, Gautier T, et al. Influence of CO on Titan atmospheric reactivity [J]. Icarus, 2014, 238: 221-229.