Anion yields produced by low-energy electron impact on condensed hydrocarbon films

Journal Article · Thu Jun 13 00:00:00 EDT 1991 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100165a054· OSTI ID:5973319

Rowntree, P; Parenteau, L; Sanche, L ^[1]

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1. Univ. de Sherbrooke, Quebec (Canada)

Low-energy (0-20 eV) electron impact on thin condensed hydrocarbon films is observed to produce, via dissociative attachment and dipolar dissociation, significant yields of H{sup {minus}} and much lower yields of CH{sub n}{sup {minus}} (n = 1-3) fragment anions. These yields have been measured as a function of incident electron energy and film thickness for the saturated n-C{sub n}H{sub 2n+2} (n = 2, 4-9) and for the unsaturated 1-C{sub n}H{sub 2n} (n = 2-4) hydrocarbons. Each type of anion desorbing from the saturated hydrocarbon films exhibits a single dissociative attachment resonance at approximately 10 eV, the energy of which is found to vary only slightly with hydrocarbon chain length, in contrast with the trends observed in the gas phase for H{sup {minus}} formation from these systems. The hydrogen anion yields produced from the unsaturated species are similar to those from the saturated species, while the larger fragment anions typically demonstrate asymmetric or bimodal yield distributions. The thickness dependence of the anion yields suggests that the observed H{sup {minus}} anions are formed in the uppermost 3-5 layers of the film, while the larger desorbing anion fragments arise from the first 1-2 layers.

• OSTI ID: 5973319
• Journal Information: Journal of Physical Chemistry; (United States), Vol. 95:12; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
HYDROCARBONS
CHEMICAL RADIATION EFFECTS
ANIONS
DECOMPOSITION
DESORPTION
ELECTRON BEAM TARGETS
ELECTRON BEAMS
EV RANGE 01-10
EV RANGE 10-100
EXPERIMENTAL DATA
FILMS
MASS SPECTROSCOPY
SURFACES
BEAMS
CHARGED PARTICLES
CHEMICAL REACTIONS
DATA
ENERGY RANGE
EV RANGE
INFORMATION
IONS
LEPTON BEAMS
NUMERICAL DATA
ORGANIC COMPOUNDS
PARTICLE BEAMS
RADIATION EFFECTS
SPECTROSCOPY
TARGETS
400600* - Radiation Chemistry