  We investigate the electronic structure of 4d transition metal oxides, CaRuO3
and SrRuO3. The analysis of the photoemission spectra reveals significantly
weak electron correlation strength (U/W ~ 0.2) as expected in 4d systems and
resolves the long standing issue that arose due to the prediction of large U/W
similar to 3d-systems. It is shown that the bulk spectra, thermodynamic
parameters and optical properties in these systems can consistently be
described using first principle approaches. The observation of different
surface and bulk electronic structures in these weakly correlated 4d systems is
unusual.

Strongly Correlated Electrons