Shape resonances of oriented molecules: ab initio theory and experiment on hydrocarbon molecules
We report ab initio calculations of the x-ray absorption cross section for the near edge x-ray absorption fine structure of C2H6, and C2H4, and C2H2 at the C K-edge, based on a full multiple scattering formalism. The angular dependence of the electric dipole transition in the calculations as well as the angular dependent experiments for the oriented molecules give a good opportunity to compare both. The resonance can be assigned to a sigma(*) shape resonance. The multiple scattering formalism and the experiment agree well and thereby support the existence of such features in the spectra.
Haack
N
Institut fur Experimentalphysik, Freie Universitat Berlin, Arnimallee 14, D-14195 Berlin-Dahlem, Germany.
Ceballos
G
Wende
H
Baberschke
K
Arvanitis
D
Ankudinov
AL
Rehr
JJ