DYNAMICAL ASPECTS OF PHOTOELECTRON ANGULAR DISTRIBUTIONS FROM K-SHELLS OF ORIENTED CO2 K. Ito*, J. Adachi#, Y. Hikosaka*, S. Motoki*,$, M.Sano*, K. Soejima%, A. Yagishita*, Kwanghsi Wang& and V. McKoy& *Photon Factory, Institute of Materials Structure Science, KEK, Tsukuba 305-0801, Japan #Institute of Molecular Science, Okazaki 444-0864, Japan $Graduate School of Science and Technology, Chiba University, Chiba 263-0022, Japan %Graduate School of Science and Technology, Niigata University, Niigata 950-2102, Japan &A. A. Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, CA 91125, U. S. A. The angular distributions of O-1s photoelectrons from oriented CO2 molecules have been measured by detecting the photoelectrons in coincidence with the fragment ions. It is found that the angular distributions in parallel transition show dramatic changes across the sg and su shape resonances. Ab-initio calculations suggest that the present experimental results are ascribed to the symmetry breaking due to the anti-symmetric motion of the oxygen atom in the O-1s photoionization processes.