Naoki WATANABE,* Jun-ichi ADACHI, Koichi SOEJIMA,** Eiji SHIGEMASA,*** Akira YAGISHITA,*** N. G. FOMINYKH**** and A. A. PAVLYCHEV**** (*Hokkaido Univ., **Niigata Univ., ***KEK-PF, ****St. Petersburg Univ.)
[Phys. Rev. Lett. 78, 4910 (1997)]
Angular distributions of 1s(sigma)g,u photoelectrons from CO2 molecules, oriented parallel to the electric vector of incident light, have been measured. The angular distribution patterns at (sigma)g* and (sigma)u* shape resonances are significantly different from those expected in the virtual molecular orbitals concept. The analyses of the patterns have made it clear that the mixing of outgoing photoelectron partial waves and the interference between them are responsible for the observed patterns, unlike N2 photoionization. Calculations based on a quasiatomic model have reproduced the observed patterns fairly well.