Hydrogen electron irradiation

Carbon nanotubes inevitably contain defects, whose extent depends on the fabrication method but also on the CNT post-treatments. As already seen, oxidizing treatments, such as acid, plasma or electrochemical, can introduce defects that play an important role in the electrochemical performance of CNT electrodes. For instance, Collins and coworkers have published an interesting way to introduce very controlled functionalization points or defects on individual SWNTs by electrochemical means [96]. Other methodologies to introduce artificial defects comprise argon, hydrogen and electron irradiation. Under this context, a number of recent works have appeared with the goal of tailoring the electrochemical behavior of CNT surfaces by the controlled introduction of defects [97, 98]. 

Fig. 4-1. Second derivative ESR spectra observed for hydrogen atom (al and a2) and deuterium atom (bl, b2, and b3) with 2.8 MeV electron irradiation of liquid methane ( and deuteromethane) at 98 K. The observed spacings and the shifts from the first-order positions are indicated. The first-order positions of both hydrogen and deuterium atoms center at a field (indicated by the arrow) which corresponds to g = 2.00223. The tallest signal indicated by c is due to CDa- (Reproduced from Ref. [ 1] by permission from The American Institute of Physics)...

Nicholson was the first to observe a correlation between the cracking pattern and the photochemical behaviour of the aliphatic ketones. Sharkey et observed the rearrangement peaks of simple ketone molecule-ions in the electron impact investigation of ketones with a hydrogen atom on the y-carbon atom however, such peaks could not be detected when ketones having no y-hydrogens were irradiated. The same simple ketones were formed in primary step II of the photolysis. 

Garand, E. and RA. Rowntree. 2005. The mechanism of hydrogen formation induced by low-energy electron irradiation of hexadecanethiol self-assembled monolayers. J Phys Chem B 109 12927-12934. 

Jones, J. D., Mahajan, K. K., Williams, W. H., Ecton, P. A., and J. M. Perez. 2010. Formation of graphane and partially hydrogenated graphene by electron irradiation of adsorbates on grapheme. Carbon48 2335-2340. 

Fourier transform IR measurements were used to investigate PVDF films which had been irradiated by means of heavy ions (krypton ions) and electrons. Irradiation with krypton ions was carried out in the presence of helium, hydrogen, deuterium and oxygen. Triple bonds were characteristic of krypton ion irradiation. Double bonds (isolated and conjugated) occurred with both types of irradiation but concentrations were higher with the krypton radiation. The results, including the role of oxygen on the chemical modifications, were discussed. 36 refs. 

Nippon Carbon has obtained a near-stoichiometric fibre, the Hi-Nicalon Type S, from a PCS cured, in a hydrogen rich environment, by electron irradiation using a modified Hi-Nicalon process . It is claimed that the excess carbon is reduced from C/Si = 1.39 for the Hi-Nicalon to 1.05 for the Hi-Nicalon Type S. 

In most cases, the packing of the spacers is mainly controlled by van der Waals [1-8] and aromatic, e.g., jr-jr, [61-63] interactions. There are few examples of hydrogen bonds, (e.g., due to the presence of amide moieties [64]) or of dipole-dipole interactions (e.g., due to sulphone groups) between adjacent spacers [65]. Covalent bonds between atoms of adjacent spacers are only occasionally reported, as in the case of the formation of C-C bonds between alkyl chains, induced by electron irradiation [66]. Disorder in the spacer ensemble may be due to the head and tail groups in the case of bulky groups, the density of the molecules on the substrate is low. As a result, the forces between adjacent spacers are weak, disorder arises in the spacer moieties, and consequently in the SAM as a whole. 

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