Inner-shell photoelectron angular distributions from fixed-in-space OCS molecules

The photoelectron angular distributions (PADs) for the OCS O 1s, C 1s and S 2p(1/2), 2p(3/2) ionization have been measured in the shape resonance region. The experimental results have been compared with multiple scattering X alpha calculations. It is found that the position of an ionized atom play's a significant role. For a central position (C 1s ionization) the PAD is relatively symmetric. In the case of S 2p and O 1s ionization, electrons are emitted highly preferentially in a solid cone directed from the molecular centre to the respective S or O atom. For the OCS O 1s ionization the S-C fragment plays a very effective role as a 'scatterer' and in the shape resonance region nearly all intensity in PAD is concentrated in the lobe between theta = 50 degrees and 80 degrees, but not along the molecular axis.