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For emission out of the molecule along the molecular axis, the direct wave interferes with an electron wave that is scattered an odd number of times and dominated by singlescattering (66% back-scattering), whereas for emission into the molecule, the direct

Angular distributions of C͑1s͒ photoelectrons emitted from oriented CO molecules were measured using a new method: mass and angle-resolved photoelectron-photoion coincidence spectroscopy. Along with the angular momentum composition of the photoelectron wave, the experiment reveals pronounced forward-backward asymmetries in the photoemission intensity with respect to the molecular orientation. This asymmetry, being observed for the first time in molecular photoionization, is interpreted in terms of multiple scattering effects. Calculations using the MS-Xa method show good quantitative agreement with the presented experimental results. [S0031-9007(97)04163-X]

Angle-resolved photoelectron spectra of gaseous C60 were recorded in the photon energy regions from 21 to 108 eV and from 295 to 320 eV. Partial cross sections o and the angular distribution anisotropy parameter P vary significantly with photon energy, particularly in the near-threshold region of the valence and the core ionization regimes. Some of these effects may be attributed to scattering of the outgoing photoelectron by the atoms of the ionized C60 molecule. Our results indicate that the observed satellites of the C(1s) main line are most likely of shake-up character. Low-energy electrons emitted below the shake-off threshold indicate the occurrence of K-shell vacancy filling double Auger decay. PACS number(s): 36.40.Mr, 33.80. -b, 33.60. -q