Electron impact excitation cross section studies of methane and acetylene

Journal Article · Sat Feb 28 23:00:00 EST 1987 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.452077· OSTI ID:6838601

Pang, K D; Ajello, J M; Franklin, B; Shemansky, D E

We have measured the electron impact emission cross sections for CH/sub 4/ and C/sub 2/H/sub 2/ at 200 eV in a crossed beam laboratory system. Included in the study are all vacuum ultraviolet (VUV) emission features from 40 to 200 nm. The features are entirely from the atomic dissociation fragments (C I, C II, and H). The Lyman series of H is observed to truncate near principal quantum number n = 10 due to the long lifetime and to the high kinetic energy of the excited H fragments. The threshold region of the excitation functions has been measured at an energy resolution of 0.2--1.0 eV for the Lyman-..cap alpha.. and Lyman-..beta.. transitions of H and C I (165.7, 193.1 nm) multiplets; and several distinct appearance potentials (AP) have been detected. For example, appearance potentials of Lyman-..cap alpha.. from dissociation of CH/sub 4/ and C/sub 2/H/sub 2/ are noted at several energies, including the first observations of a Lyman-..cap alpha.. AP from C/sub 2/H/sub 2/ at 16.3 eV.

• Research Organization: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109
• OSTI ID: 6838601
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 86:5; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ACETYLENE
ALKANES
ALKYNES
BEAMS
COLLIDING BEAMS
COLLISIONS
CROSS SECTIONS
DISSOCIATION
ELECTRON BEAMS
ELECTRON COLLISIONS
ELECTRON-MOLECULE COLLISIONS
EMISSION SPECTRA
ENERGY-LEVEL TRANSITIONS
EXCITATION
HYDROCARBONS
LEPTON BEAMS
LYMAN LINES
METHANE
MOLECULAR BEAMS
MOLECULE COLLISIONS
ORGANIC COMPOUNDS
PARTICLE BEAMS
SPECTRA
ULTRAVIOLET SPECTRA