Photoelectron spectroscopy of ethylene, isobutylene, trimethylethylene, and tetramethylethylene at variable angle

Journal Article · Mon Oct 15 04:00:00 EDT 1979 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.438739· OSTI ID:5867381

Mintz, D M; Kuppermann, A

Using a HeI line 58.4 nm source lamp, photoelectron angular distributions were measured for the series of four olefins: ethylene, isobutylene (2-methyl-propene), trimethylethylene (2-methyl-2-butene), and tetramethylethylene (2,3-dimethyl-2-butene). From these, the asymmetry parameter ..beta.. as a function of photoelectron energy was obtained for each of these molecules. The following important effects in the behavior of ..beta.. are observed: (a) In the ..pi.. orbital ionization regions of the spectrum of each molecule, ..beta.. increases with increasing electron energy across the vibrational envelopes. (b) With increasing methyl substitution (and at a fixed photoelectron enegy) ..beta.. for this band decreases. (c) In the region of the spectra of each of the methyl-substituted ethylenes involving several 2psigma bands, this energy dependence of ..beta.. behaves as if they constituted a single band, in spite of the widely differing orbital symmetries. (d) Over most of the 2psigma region of each molecule, ..beta.. decreases with increasing photoelectron energy, except for the high ionization potential end of this region, where ..beta.. increases instead. We attribute effects (b) and (d) to sigma--..pi.. orbital mixing.

• Research Organization: Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125
• OSTI ID: 5867381
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 71:8; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

2-METHYLPROPENE
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400301 -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
ALCOHOLS
ALKENES
ANGULAR DISTRIBUTION
BUTENES
DISTRIBUTION
ELECTRON SPECTROSCOPY
ETHYLENE
GLYCOLS
HYDROCARBONS
HYDROXY COMPOUNDS
ORGANIC COMPOUNDS
PHOTOELECTRON SPECTROSCOPY
PINACOL
SPECTROSCOPY