# Osnabrück 2002 – wissenschaftliches Programm

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# MO: Molekülphysik

## MO 15: Photoionisation II (gemeinsam mit FV Atomphysik)

### MO 15.8: Vortrag

### Donnerstag, 7. März 2002, 15:45–16:00, HS 15/E10

**Coherence Phenomena in the Photoelectron Emission from Homonuclear Molecules** — •Daniel Rolles^{1}, Rainer Hentges^{1}, Georg Prümper^{1}, Uwe Becker^{1}, and Ricardo Dìez Muiño^{2} — ^{1}Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany — ^{2}Donostia International Physics Center, San Sebastian, Spain

Photoelectron angular distributions (PAD’s) in the molecule frame have been
calculated using the Multiple Scattering in Non-Spherical Potentials
(MSNSP) approach for different orientations of the molecular axis with
respect to the electric vector of the light. It is shown that using either
a coherent or incoherent superposition of the electron flux from both
atomic sites leads to the same angular distributions if the two symmetry
components *gerade* and *ungerade* are unresolved. This has been
proven by comparing to recent COLTRIMS data for the N_{2}(1s)
photoemission. However, considering the two components separately, the
corresponding PAD’s are markedly different in the coherent model. When
choosing the electron emission direction along the electric vector and the
orientation of the molecular axis predominantly perpendicular to it, the
u-component is suppressed in the PES, whereas choosing a molecular
orientation at an angle of 45^{∘} enhances this component. Newly
measured PAD’s are analysed with respect to these predictions and the
results favour the coherent emission model strongly. Concerning the
separate *gerade* and *ungerade* components, the results are also
compared to recent TDLDA calculations for the photoelectron angular
distributions from randomly oriented N_{2} molecules. The preliminary
analysis shows very good agreement.