Abstract
We have produced thin solid films of hydrogenated amorphous carbon (HAC) by vapor deposition in vacuum and have investigated the structure and infrared spectra of these materials under conditions in which they are at the point of decomposition. We find that the IR absorption spectrum of HAC under these conditions contains all the major spectral components seen in emission in nebulae. In addition, high-resolution scanning tunneling microscopy of HAC prior to decomposition reveals protographitic islands with dimensions ~1-5 nm showing that polycyclic aromatic hydrocarbon (PAH)-like molecular groups evolve from HAC. These experimental results suggest for the first time how PAHs and HAC may be related and how PAH molecules could evolve from HAC in regions of high excitation. The material produced as HAC decomposes is a very low density carbonaceous aerogel consisting primarily of these aromatic protographitic clusters in a weakly connected friable network. These protographitic clusters may be the source of interstellar graphite grains.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
