PMID- 21901185
OWN - NLM
STAT- MEDLINE
DCOM- 20120126
LR  - 20131121
IS  - 1463-9084 (Electronic)
IS  - 1463-9076 (Linking)
VI  - 13
IP  - 39
DP  - 2011 Oct 21
TI  - On the chemical processing of hydrocarbon surfaces by fast oxygen ions.
PG  - 17870-84
LID - 10.1039/c1cp21800j [doi]
AB  - Solid methane (CH(4)), ethane (C(2)H(6)), and ethylene (C(2)H(4)) ices 
      (thickness: 120 +/- 40 nm; 10 K), as well as high-density polyethylene (HDPE: 
      [C(2)H(4)](n)) films (thickness: 130 +/- 20 nm; 10, 100, and 300 K), were 
      irradiated with mono-energetic oxygen ions (Phi ~ 6 x 10(15) cm(-2)) of a kinetic 
      energy of 5 keV to simulate the exposure of Solar System hydrocarbon ices and 
      aerospace polymers to oxygen ions sourced from the solar wind and planetary 
      magnetospheres. On-line Fourier-transform infrared spectroscopy (FTIR) was used 
      to identify the following O(+) induced reaction pathways in the solid-state: (i) 
      ethane formation from methane ice via recombination of methyl (CH(3)) radicals, 
      (ii) ethane conversion back to methane via methylene (CH(2)) retro-insertion, 
      (iii) ethane decomposing to acetylene via ethylene through successive hydrogen 
      elimination steps, and (iv) ethylene conversion to acetylene via hydrogen 
      elimination. No changes were observed in the irradiated PE samples via infrared 
      spectroscopy. In addition, mass spectrometry detected small abundances of 
      methanol (CH(3)OH) sublimed from the irradiated methane and ethane condensates 
      during controlled heating. The detection of methanol suggests an implantation and 
      neutralization of the oxygen ions within the surface where atomic oxygen (O) then 
      undergoes insertion into a C-H bond of methane. Atomic hydrogen (H) recombination 
      in forming molecular hydrogen and recombination of implanted oxygen atoms to 
      molecular oxygen (O(2)) are also inferred to proceed at high cross-sections. A 
      comparison of the reaction rates and product yields to those obtained from 
      experiments involving 5 keV electrons, suggests that the chemical alteration of 
      the hydrocarbon ice samples is driven primarily by electronic stopping 
      interactions and to a lesser extent by nuclear interactions.
CI  - This journal is (c) the Owner Societies 2011
FAU - Ennis, Courtney
AU  - Ennis C
AD  - Department of Chemistry, University of Hawai'i at Manoa, Honolulu, HI 96822, USA.
FAU - Yuan, Hanqiu
AU  - Yuan H
FAU - Sibener, S J
AU  - Sibener SJ
FAU - Kaiser, Ralf I
AU  - Kaiser RI
LA  - eng
PT  - Journal Article
PT  - Research Support, U.S. Gov't, Non-P.H.S.
DEP - 20110907
PL  - England
TA  - Phys Chem Chem Phys
JT  - Physical chemistry chemical physics : PCCP
JID - 100888160
RN  - 0 (Ethylenes)
RN  - 0 (Ions)
RN  - 9002-88-4 (Polyethylene)
RN  - 91GW059KN7 (ethylene)
RN  - L99N5N533T (Ethane)
RN  - OP0UW79H66 (Methane)
RN  - S88TT14065 (Oxygen)
SB  - IM
MH  - Ethane/*chemistry
MH  - Ethylenes/*chemistry
MH  - Ions/chemistry
MH  - Kinetics
MH  - Methane/*chemistry
MH  - Oxygen/*chemistry
MH  - Particle Size
MH  - Polyethylene/*chemistry
MH  - Surface Properties
EDAT- 2011/09/09 06:00
MHDA- 2012/01/27 06:00
CRDT- 2011/09/09 06:00
PHST- 2011/09/09 06:00 [entrez]
PHST- 2011/09/09 06:00 [pubmed]
PHST- 2012/01/27 06:00 [medline]
AID - 10.1039/c1cp21800j [doi]
PST - ppublish
SO  - Phys Chem Chem Phys. 2011 Oct 21;13(39):17870-84. doi: 10.1039/c1cp21800j. Epub 
      2011 Sep 7.