WJCMP  Vol.3 No.1 , February 2013
Experimental and Theoretical Study on the Ethane and Acetylene Formation from Electron Irradiation of Methane Ices
Abstract: In this work we present an experimental and theoretical study on the formation of ethane and acetylene from solid methane condensed at 20 K and irradiated with a 500 - 3000 eV electron beam. The experiments were monitored with Thermal Desorption Spectroscopy. We observe that the electron irradiation induced a dehydrogenation of methane and a consequent formation of CHx (x = 1, 2, 3) fragments. Furthermore, in the solid during irradiation, a simple recombinetion reaction in the solid between two adjacent CHx molecules may form HC≡CH, H2C=CH2, and H3C-CH3 with a triple, double, and single carbon-carbon bond, respectively. The formed amount of ethane and acetylene increases with irradiation time and reaches a saturation value.  
Cite this paper: M. Barberio, R. Vasta, P. Barone, G. Manicò and F. Xu, "Experimental and Theoretical Study on the Ethane and Acetylene Formation from Electron Irradiation of Methane Ices," World Journal of Condensed Matter Physics, Vol. 3 No. 1, 2013, pp. 14-20. doi: 10.4236/wjcmp.2013.31003.

[1]   E. Garand and P. A. Rowntree, “The Mechanism of Hydrogen Formation Induced by Low-Energy Electron Irradiation of Hexadecanethiol Self-Assembled Monolayers,” The Journal of Physical Chemistry B, Vol. 109, No. 26, 2005, pp. 12927-12934. doi:10.1021/jp050817k

[2]   H. F. Winters, “Dissociation of Ethane by Electron Impact,” Chemical Physics, Vol. 36, No. 3, 1979, pp. 353364. doi:10.1016/0301-0104(79)85019-3

[3]   C. J. Bennet, C. S. Jamieson, Y. Osamura, R. I. Kaiser, Laboratory Studies on the Irradiation of Methane in Interstellar, Cometary, and Solar System Ices,” The Astrophysical Journal, Vol. 653, No. 1, 2006, p. 792. doi:10.1086/508561

[4]   Scheffler and Elsasser, “Physics of the Galaxy and Interstellar Matter,” Springer, Berlin, 1988.

[5]   D. C. B. Whittet, “Observations of Molecular Ices,” In: T. J. Millar and D. A. Williams, Eds., Dust and Chemistry in Astronomy, Cambridge University Press, Cambridge, 1993, p. 201.

[6]   Hollenbach and Thronson, “Interstellar Processes,” Proceedings of the Symposium on Interstellar Processes, Grand Teton National Park, 1-7 July 1986, Vol. 134 No. ,

[7]   W. A. Schutte, “Production of Organic Molecules in Interstellar Ices,” Advances in Space Research, Vol. 30, No. 6, 2002, pp. 1409-1417. doi:10.1016/S0273-1177(02)00500-8

[8]   R. I. Kaiser and K. Roessler, “Theoretical and Laboratory Studies on the Interaction of Cosmic-Ray Particles with Interstellar Ices. III. Suprathermal Chemistry-Induced Formation of Hydrocarbon Molecules in Solid Methane (CH4), Ethylene (C2H4), and Acetylene (C2H2),” The Astrophysical Journal, Vol. 503, No. 2, 1998, p. 959. doi:10.1086/306001

[9]   A. Wada, N. Mochizuki and K. Hiraoka, “Methanol Formation from Electron-Irradiated Mixed H2O/CH4 Ice at 10 K,” The Astrophysical Journal, Vol. 644, No. 1, 2006, p. 300. doi:10.1086/503380

[10]   Zheng, Jewitt, Osamura and Kaiser, “Formation of Nitrogen and Hydrogen-bearing Molecules in Solid Ammonia and Implications for Solar System and Interstellar Ices,” The Astrophysical Journal, Vol. 674, No. 2, (2008) pp. 1242. doi:10.1086/523783

[11]   P. Ehrenfreund, S. B. Charneley and D. Wooden, “Comets II,” University of Arizona Press, Tucson, 2004.

[12]   T. Y. Brooke, A. T. Tokunaga, H. A. Weaver, J. Crovisier, D. Bockelée-Morvan and D. Crisp, “Detection of Acetylene in the Infrared Spectrum of Comet Hyakutak,” Nature, Vol. 383, 1996, pp. 606-608. doi:10.1038/383606a0


[14]   M. Barberio, P. Barone, R. Vasta, G. Manicò and F. Xu, “Formation of Molecular Nitrogen and Diazene by Electron Irradiation of Solid Ammonia,” Thin Solid Film, Vol. 520, No. 16, 2012, pp. 5479-5481. doi:10.1016/j.tsf.2012.03.112

[15]   T. Shirai, et al., “Analytic Cross Sections for Electron Collisions with Hydrocarbons: CH4, C2H6, C2H4, C2H2, C3H8, and C3H6,” Atomic Data and Nuclear Data Tables, Vol. 80, No. 2, 2002, pp. 147-204. doi:10.1006/adnd.2001.0878

[16]   D. J. Alberas-Sloan and J. M. White, “Low-Energy Electron Irradiation of Methane on Pt(111),” Surface Science, Vol. 365 No. 2, 1996, pp. 212-228. doi:10.1016/0039-6028(96)00720-0


[18]   M. A. Huels, P. C. Dugal and L. Sanche, “Degradation of Functionalized Alkanethiolate Monolayers by 0 18 eV Electrons,” Journal of Chemical Physics, Vol. 118, No. 24, 2003, pp. 11168-11179. doi:10.1063/1.1574791

[19]   D. Drouin, A. R. Couture, D. Joly, X. Tastet, V. Aimez and R. Gauvin, “CASINO V2.42—A Fast and Easy-toUse Modeling Tool for Scanning Electron Microscopy and Microanalysis Users,” Scanning, Vol. 29, No. 3, 2007, p. 92.

[20]   P. Hovington, D. Drouin and R. Gauvin, “CASINO: A New Monte Carlo Code in C Language for Electron Beam intEraction—Part I: Description of the Program,” Scanning, Vol. 19, No. 1, 1997, pp. 1-14. doi:10.1002/sca.4950190101