Observation of anomalously enhanced satellite in metastable atom electron spectrum ofLaCoO3

The electron emission spectrum resulting from thermal collisions of ${\mathrm{He}}^{\mathrm{*}}$($2^3$S) atoms with ${\mathrm{LaCoO}}_3$ was measured as well as the hν-dependent photoemission spectra. The ${\mathrm{He}}^{\mathrm{*}}$ spectrum shows that the lower-lying Co 3d derived (main) bands are strongly suppressed relative to the O 2p derived bands, reflecting the spatial distribution of the initial Co 3d wave functions. On the other hand, the higher-lying Co 3d derived (satellite) band is anomalously enhanced in the ${\mathrm{He}}^{\mathrm{*}}$ spectrum. These findings are discussed on the basis of the initial and final configuration interactions, using a ${\mathrm{Co}}_2$ ${\mathrm{O}}_{11}$ cluster.