Carbon K-shell excitation of gaseous and condensed cyclic hydrocarbons: C/sub 3/H/sub 6/, C/sub 4/H/sub 8/, C/sub 5/H/sub 8/, C/sub 5/H/sub 10/, C/sub 6/H/sub 10/, C/sub 6/H/sub 12/, and C/sub 8/H/sub 8/

Journal Article · Sat Nov 01 00:00:00 EST 1986 · J. Chem. Phys.; (United States)

OSTI ID:5240499

Hitchcock, A P; Newbury, D C; Ishii, I; Stoehr, J; Horsley, J A; Redwing, R D; Johnson, A L; Sette, F

The carbon K-shell excitation spectra of gaseous cyclic hydrocarbons, both saturated (cyclopropane, cyclobutane, cyclopentane, cyclohexane) and unsaturated (cyclopentene, cyclohexene, and cyclooctatetraene), have been recorded by electron energy loss spectroscopy under dipole-dominated conditions. These are compared to the NEXAFS spectra of multilayers and monolayers of C/sub 4/H/sub 8/, C/sub 5/H/sub 8/, C/sub 6/H/sub 12/, and C/sub 8/H/sub 8/ on Pt(111). Multiple scattering X..cap alpha.. calculations of the spectra of cyclopropane, cyclobutane, and cyclohexane are also reported. In most cases the gas and solid spectra are essentially the same indicating that intramolecular transitions dominate in the condensed phase. The NEXAFS polarization dependence of the condensed phases has assisted spectral assignments and the determination of the molecular orientation in the monolayer phase. In the saturated species a sharp feature about 3 eV below the carbon 1s ionization threshold is identified as a transition to a state of mixed Rydberg/valence character with the ..pi..*(CH/sub 2/) valence component dominating. Except for cyclopropane the positions of the main sigma * resonances correlate with the C-C bond lengths in a manner similar to that reported previously for noncyclic aliphatic molecules. In the spectra of monolayer C/sub 6/H/sub 12/, C/sub 5/H/sub 8/, and C/sub 8/H/sub 8/ spectral broadening and weak additional features are observed which are attributed to molecule-surface interactions.

• Research Organization: Department of Chemistry, McMaster University, Hamilton, Canada, L8S 4M1
• OSTI ID: 5240499
• Journal Information: J. Chem. Phys.; (United States), Vol. 85:9
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
CYCLOALKANES
INNER-SHELL IONIZATION
PHOTOELECTRON SPECTROSCOPY
X-RAY SPECTRA
CYCLOALKENES
CARBON
EXCITATION
K SHELL
ALKANES
ALKENES
ELECTRON SPECTROSCOPY
ELECTRONIC STRUCTURE
ELEMENTS
ENERGY-LEVEL TRANSITIONS
HYDROCARBONS
IONIZATION
NONMETALS
ORGANIC COMPOUNDS
SPECTRA
SPECTROSCOPY
640302* - Atomic
Molecular & Chemical Physics- Atomic & Molecular Properties & Theory