Ramanspectra of hydrocarbons formed in carbon nanotubes - a theoretical study

Author(s)
Jeno Kuerti, Janos Koltai, Balint Gyimesi, Hans Kuzmany
Abstract

Recent experimental results based on Raman spectroscopy and mass spectroscopy showed that an appropriate heat treatment of small diameter carbon nanotubes filled with ferrocene molecules results in the formation of hydrocarbon molecules. However, the exact nature of these molecules is still unknown. In order to find possible candidates, we performed density functional theory calculations of the structure, electronic transition energies, and Raman spectrum for a large set of hydrocarbon molecules, including oligoenes and polyaromatic hydrocarbons. To follow the effect of deuteration in the Raman spectra we varied the mass of hydrogen atom from 1 to 2 by 0.1 steps. With increasing mass, the position of the lines red shifted as expected. However, in some rare occasions, the intensity of the red shifted line dramatically decreased and at the same time, an originally weak line gained large intensity at a nearby higher frequency. This can be interpreted in an experiment as an apparent blue shift. From a comparison of the calculations with experiments, based on molecular weight, excitation energy, and Raman spectrum (for both hydrogenated and deuterated forms) either quaterrylene (dimer of perylene) or the dimer of the 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) is the most likely product of the heat treatment.

Organisation(s)
Electronic Properties of Materials
External organisation(s)
Eötvös Loránd University Budapest
Journal
Physica Status Solidi. B: Basic Research
Volume
252
Pages
2541-2545
No. of pages
5
ISSN
0370-1972
DOI
https://doi.org/10.1002/pssb.201552359
Publication date
11-2015
Peer reviewed
Yes
Austrian Fields of Science 2012
103018 Materials physics
Keywords
ASJC Scopus subject areas
Electronic, Optical and Magnetic Materials, Condensed Matter Physics
Portal url
https://ucris.univie.ac.at/portal/en/publications/ramanspectra-of-hydrocarbons-formed-in-carbon-nanotubes--a-theoretical-study(bc9677eb-62f5-4195-b773-3a9030ee54aa).html