Publication Date:
2014-12-27
Description:
We have studied the molecular products of the photo-induced decomposition of hydrogenated amorphous carbon (HAC) and solid hexane, C 6 H 14 , using mass spectroscopy. Mass spectra of HAC are dominated by simple hydrocarbon molecules having fewer than four carbon atoms. Notable products include C 3 H 2 , phenyl, C 6 H 5 , benzene, C 6 H 6 , and a variety of partially dehydrogenated alkane molecules with the composition C n H 2 n -1 . Hexane, chosen as a representative solid alkane, has a more complex mass spectrum which includes C n and a number of hydrocarbon molecules with up to 10 carbon atoms. As alkyl radicals, C n H 2 n -1 , are commonly found in the decomposition of alkanes, we have used high precision density functional theory to simulate the infrared spectrum of 1-, 2-, and 3-hexyl radicals as well as that of the 3-hexyl ion, C 6 H 13 + . The latter could be detectable in interstellar/circumstellar sources via a strong feature at 3.66 μm. The appearance of C 3 H 2 as a decomposition product of photodissociated HAC may be related to the ubiquitous presence of c-C 3 H 2 in the interstellar medium. The production of such molecules in the interstellar medium through a ‘top-down’ chemistry deriving from the decomposition of HAC is discussed.
Print ISSN:
0035-8711
Electronic ISSN:
1365-2966
Topics:
Physics
