%0 Journal Article %T Theory of polarization-averaged core-level molecular-frame photoelectron angular distributions: I. A Full-potential method and its application to dissociating carbon monoxide dication %+ University of Toyama %+ Tohoku University [Sendai] %+ Institut de Physique de Rennes (IPR) %A Ota, Fukiko %A Yamazaki, Kaoru %A Sébilleau, Didier %A Ueda, Kiyoshi %A Hatada, Keisuke %Z KAKENHI under Grant No.18K05027, Japan Society for the Promotion of Science %Z Building of Consortia for the Development of HumanResources in Science and Technology, MEXT %Z Dynamic Alliance for Open Innovation Bridging Human,Environment and Materials program and CooperativeResearch Program of “Network Joint Research Center forMaterials and Devices”. %< avec comité de lecture %@ 0953-4075 %J Journal of Physics B: Atomic, Molecular and Optical Physics %I IOP Publishing %V 54 %N 2 %P 024003 %8 2021-01-20 %D 2021 %R 10.1088/1361-6455/abd06d %Z Physics [physics]Journal articles %X We present a theoretical study of the polarization-averaged molecular-frame photoelectron angular distributions (PA-MFPADs) emitted from the 1s orbital of oxygen atoms of dissociating dicationic carbon monoxide CO2+. Due to the polarization-average, the contribution of the direct wave of the photoelectron which represents the largest contribution to the MFPADs is removed, so that the PA-MFPADs clearly show the details of the scattering image of the photoelectron. As a result, it is necessary to employ an accurate theory for the theoretical analysis of the continuum state. In this study, we apply a Full-potential Multiple Scattering theory, where the space is partitioned into Voronoi polyhedra and truncated spheres, in order to take into account the electron charge density outside the physical atomic spheres. We do not use the spherical harmonics expansion of the cell shape functions to avoid divergence problems. The potentials in the scattering cells are computed using the Multiconfigurational Second-Order Perturbation Theory Restricted Active Space (RASPT2) method in order to take into account the influence of the core hole in the electron charge density in the final state, so that to a realistic relaxation can be achieved. We show that the Full-potential treatment plays an important role in the PA-MFPADs at a photoelectron kinetic energy of 100 eV. By contrast, the PA-MFPADs are not sensitive to any type of major excited states in the Auger final state. We also study the dynamics of the CO2+ dissociation. We find that the PA-MFPADs dramatically change their shape as a function of the C-O bond length. %G English %L hal-03103799 %U https://univ-rennes.hal.science/hal-03103799 %~ UNIV-RENNES1 %~ CNRS %~ OSUR %~ IPR %~ IPR-MN %~ ZZ-IPR-MN %~ STATS-UR1 %~ UR1-SPM %~ UR1-UFR-SPM %~ UR1-HAL %~ UR1-SDLM %~ TEST-UR-CSS %~ UNIV-RENNES %~ UR1-MMS